I have a set of 416 head castings, and I'll be porting those shortly (thanks for the awesome thread Sitting Bull!). The valves I'll use are 1.94/1.60. I'd like to stick a Crane 266 cam in it, along with a set of Crane aluminum roller rockers. Should I get a new set of pushrods for her, or just reuse the old ones? Also, can I keep my stock torque converter? If not, why? If I must get a new converter, can you recommend a good one to me?

Also, on kindof a side note... can the AIR injection B.S. on the stock exhaust manifold be removed without any significant increase in emissions? I'm guessing I can find plugs at any autoparts store to take care of those holes. Once I get some new headers, I'll just forget about that stuff all together. I think Hooker Shorties will fit nicely there. Thanks!

 

Only reason to keep air for emissions purposes is to pass a visual check. Its completely useless otherwise. The holes are oddball, wont find an exact plug, at least I have never seen one. A pipe thread plug will work, I think its 1/4"NPT that works.

 

Wow! It is nice to have someone actually state that they appreciate your work and for trying to help by sharing your experiences. (I had a supposed "friend" tell me I was a "bother" tonight, because I actually believed what she told me, so it REALLY is nice to see some honesty in human relations this evening.)

If the current pushrods are still straight there is no point in replacing them.

I think the stock torque converter should still work fine with the Crane PM 266. My stock 1400 rpm converter is working perfectly well with my PM 260, which is only slightly different on the intake lift. .427 vs .440 for the PM 266.

 

you can weld the holes shut, or drill and tap them to a standard size and plug them. for push rod are you simplying refering to replacing them with new or differant length. as a rule for every .050 to .100 lift increase you'd want to increase push rod length .100. what you have to do is actually check it with a length checker and watch the geometry of the rocker on the valve tip. look in comp or lunati catalogs and do a search here. there is some over lap and some lee way on length. if you're just wanting to replace them don't unless they're bent or worn. good chance higher stall would be better, but factory might work ok. i wouldn't run aluminum rockers on the street unless you figure on replacing them i nthe future.

 

I have used that exact cam with stock pushrods and stock heads several times- everything lines up like a charm, rocker arm geometry is dead-on perfect if you set valve lash about 3/4 - 1 turn down from zero lash.

 

I've heard that the aluminum rollers form stress fractures over time and break, but I've never seen it first hand. Would I be better off just getting a set of the Crane steel roller tip rockers?

Sitting Bull, I was serious about that thread! That helped me out a f*****g lot! I don't know if you remember or not, but we had talked about me wanting to move to Montreal this winter on another thread. How do you think your car will handle the cold with that cam? I don't want to drive my car in the snow and watch the salt eat it up, but if I have to I guess I will...

What kind of intake are you running? The dyno numbers you posted are pretty encouraging, and I'd like something similar. That's a nice long curve with a healthy peak for a 305!

 

Glad it could help--that's why I decided to post it.

What heads have you done? Post a few pics if you have them.

Yeah, I remember the thread. Mig29 was gonna let you live at his place. Is that where you are? How did you elude the immigration gendarmes? The Québecois are a kind of tribal lot, as you've no doubt discovered. But they are also a fun-loving bunch and I'll bet that is what attracted you to them in the first place. Most jazz musicians, for instance, place Montreal at the top of their favourite places to perform because the average person has a well developed musical appreciation.

This Crane PM 260 cam idles like a kitten, more or less. My idle mix is a little too rich at the moment so that is adding a tiny burble to it when in gear at idle. But it is a simple fix and isn't really a problem anyway.

But when I boot it and the rpms hit the 3000 mark--WOW!!!

Those big old QJet secondaries suddenly open with a ROAR and it literally jumps forward like someone hit it with an extra 75 hp or so!

Man, what a difference!!! :hail: :hail: :hail:

And the exhaust tone has changed COMPLETELY! I've never run into this before. It was a low rumble prior to the heads and cam. Now it has this lower-midrange rap to it that is very pronounced. It comes on almost immediately off idle and sounds extremely high performance and tough. I like it, other than the fact it a fair bit louder now than it was before. I never expected that. It is almost as though the compression went up two full points--but it hasn't! I'm running a Crane vacuum advance kit in the HEI distributor and 16* of initial advance, all on 87 octane gas! It is just a Walker Quiet Flow muffler with 3 inch inlet and dual 2 1/2 inch outlets. It just ain't quiet anymore!

All in all, this is how a thirdgen should perform. It is extremely responsive to the pedal now. When I want to pass someone it is no problem. That spot 15 cars up is mine now, anytime I want to go and take it. 99% of the cars on the road here simply aren't in the same class, period

I can't see this engine giving me troubles in the winter. It runs like a champ. And Calgary gets a lot colder in the winter than Montreal. You'll have no trouble, I'm positive.

PS I've gone from 16.5 mpg around town to 15.3 or so. I think I can get that back up there when I retune the idle mix and what not. Plus I was putting the pedal to the metal left, right and centre this last tankfull, so I might not have lost anything. (Note how you must spell "centre" and "colour" from now on )

OOPS! I'm running a vanilla grade Edelbrock Performer. It fits the gaskets perfectly, as do the heads. The rest is in the sig.

 

I haven't actually done the porting job yet, but I've got a set of '416' heads that look pretty clean. I'm anxious to start, but money flow might get in the way of completion before I move.

No, I'm not at MIG's house although I'm really grateful to him for even offering! How to escape the cold clammy clutches of the immigration gendarmes??? Well, that's a bit of a story in itself...
I'm trying to get my current divorce finalized so I can be done with all of that. While I was in Montreal in July my girlfriend contacted the immigration offices asking for information, and I've been beating them up with e-mail as well. Their answer? "Just get married." That really freaked me out at the beginning, but I guess you'd have to be me to understand. lol She said she'd do that in a heartbeat so that will probably be what happens. You know one of the coolest things about that girl? She freaking loves my third gen. She ROCKS!

That description of your engine's performance has got me really anxious to get started! Damn it! Why can't I make more money? lol

You're right about the Quebecois being pretty crazy! They're definately my kind of people. I think I'll fit right in too, as soon as my French gets a little better. I loved it there in July and I think it's the perfect place to live.

I got the heads off a complete '85 t/a. I'm pulling the ground effects too, since mine are really jacked. Here's the thing though: I've got a 700R4 in my '84, and the '85 has a t-5. How about sticking the manual in my car? I was thinking about it all last week, and I don't know if it would be worth it. What do you think?

 

I'd built up your motor the same way Sitting Bull did.
Use the same PowerMax 260 cam. Especially if you are using the stock torque converter. As you go higher in cam duration the
low end torque really starts going away, requiring a high stall converter for best perf. The 260H cam will give you plenty of power to 5500+ rpm in a 305 with ported heads, while maintaining the low end flexability. Be sure to use a thin "shim gasket" when installing your ported 416's to maintain the compression ratio.
You'll have to check into the Emmissions laws in Quebec to see
whether It's worth removing the A.I.R. system from your car.
Definatly get some headers thou. Good Luck

 

To tell you the truth, the older I get the more I like an automatic transmission. I especially like overdrive and that steep first gear in the 700r4. A manual is an option, if you like shifting gears all the time. It's really up to you, as I don't think it would be a tremendous amount of work to convert over. I think there might even be a tech article on it here.

Good luck with the new wife!

 

Sticking with the 260 is fair enough I guess. I was thinking about maybe even squeezing just a little more juice out of that 305. Thinking about it even more, I think that maybe the bigger exhaust valve might help out a little.

Bull, what kind of jets are you running in your carb? I know I need some work on my carb, but I've been slacking because of my work schedule. It's really murder. I've already got an Accel Supercoil that seems to put out some pretty good spark. The coil coupled with the Accel wires feel much better than stock. I think maybe you're right about keeping the automatic. I'm guess I am a little lazy sometimes. lol I do need to find a posi unit. That crappy open end gear really gets on my nerves.

My girlfriend's stepfather said that the only time a vehicle has to be inspected in Quebec is when it is first registered there from an outside province. I'm sure I'll be in that category, but I have to do some research on just what they require. I'll be really happy if they say "Your windshield is good and your lights work. Get out of here!"

 

The QJet is stock on the primary side. I don't know the jet size or the rods. On the secondaries it is a B hanger and AY rods. They were the closest to DRs that I could find.

You will find this mockup interesting. It is what sold me on the Crane PowerMax 260 instead of the 266, along with a simulation F-Bird'88 did for me comparing the two. As you can see, with my 305 and its parts there is no advantage anywhere to using the larger cam. In fact, the 260 has more hp and toque throughout the useable rpm range. Surprised me, too! If you are shooting for a motor identical to mine, this says "use the 260!"

 

Here is the Crane 260 compared to the Comp XE 256. It looks marginally better torque-wise yet has a tight 110 LSA. The exhaust lift is identical for both cams, but the Crane has a nicer 112 LSA for a 305, which means a better, more stable idle, and also about 10 more peak hp.

 

And finally, a comparison with the Comp XE 262 cam. It also sports a 110 LSA and even more lift and duration than any of the previous cams but does not add anything significant enough to make one favour it over the Crane 260. Additionally, Comp does not recommend it for a 305 due to low vacuum qualities that would affect the power brakes.

All in all, the Crane PowerMax 260 appears to be the ideal cam for a one hp per cubic inch 305 buildup, superior throughout the useable rpm range to every other cam commonly available today.

 

sitting bull- could you please email me your ported head air flow file?

thanx!

 

ROFLMAO at that one. It never ceases to amze me how ultra conservative cam manufacturers are. I've seen a comp 280 magnum (230 @ 0.050, 110 LSA) in a 305 and the power brakes worked just fine, even making barely 11" of vacuum at idle.

Not saying bigger is always better, just that i'm amazed that they'd warn of power brake problems with such a mild cam.

 

I also know of people using the XE 262 on a 305 who say they are doing OK brakes-wise. But a 110 LSA is not really very good on a daily driven 305, at least compared to a 112 LSA cam like the Crane PM 260. And when the XE 262 has no power advantages, there is no reason to use it.

Take the nice idle on the 260 and be happy

 

The powermax 260 is an outdated, old school grind. The XE 262 is a modern cam profile, superior in every way. A quick comparison of their specs proves this point. The crane has sluggish ramp rates while the comp gets the valves open quickly to let them do what they need to do, flow air.

Seat duration (the MOST important determinant of how a cam idles):
262/270 vs. 260/272 - basically a wash

Duration @ 0.050 (most important number to determine a cam's power potential)
218/224 vs. 204/216 - the comp XE hands the old tech crane it's *** here

lift:
.462/.469 vs. .427/.454 - again the crane loses it's ***

And the 110 vs. 112 LSA is not going to make that big of a difference in idle quality.

I'm very happy that you plugged numbers into a calculator to form your opinion, but in practice (which is what really matters after all) most guys running the XE262 in 305s are running 13s @ over 100mph. Most guys running the ancient 204/214 grind run times that can EASILY be matched by stock cammed cars. Feel free to look around and i think you'll see that the results easily speak for themself. Or would you rather just keep bench racing.

 

Well, my engine combination runs very well and keeps me happy. I consulted with lots of people and had several programs run simulations to find the best parts. F-Bird'88, RB83L69, Damon, five7kid and others helped out a lot, too.

I'm not particularly interested in racing it in the quarter. I just want a clean, fast and reliable street machine for daily driving. That it will do mid-14s in the quarter is icing on the cake.

As you can see, it is not just some lucky stab in the dark. I appreciate your insights, Ed, but I still don't see any advantage to the XE 262. I'd need a torque converter to deal with it and try for 13s, and I'm not interested in that at the moment, either.

If you lived where it hits -40* every winter, you'd understand my choices completely

And you are comparing apples to oranges. The Crane 260 was developed to compete against the Comp XE 250, which it does quite handily. The XE 262 is better compared to the Crane PM 272, which according to Crane's ads quite outpowers the Comp by 10 hp. Also, Crane states that their PowerMax line is newly engineered, so I don't think it is some dusty old design. My date of manufacture was June 11, 2002.

And there is NO way that any 305 identical to mine, but using a peanut cam, is going to keep up, period.

 

Ed: You have to keep in mind that Crane hyd cams are measured @.004" for seat duration while Comp cams are
measured at .006". Thus the longer seat duration numbers.
If, a Crane Powermax and a Comp Extreme cam of the same .050" duration are measured at a common lift point for seat duration (say .006") you'll find the Crane comes out on top most of the time ( more intense profile). These are modern fast action Asymetrical grinds that take full advantage of the available lifter diameter while providing smooth valvetrain action for long life.
There is nothing outdated about these designs.
A lot of "New" cam companies either worked for, apprenticed under, or are still playing catchup to some of the Oldies
like Harvey Crane, Ed Iskenderian and Bruce Crower.
A relativley stock 305 is very easy to "over cam" in actual in the car performance.

In the real world, a motor wants what it wants for a cam profile,
not what looks better or newer on paper or in a magazine ad.

All you need is a day dynoing a motor, with a "box o' cams" to
find this out. There is a lot more to it than the numbers reveal.

 

OK, i submit, if your goal is to beat peanut cammed cars i'm sure you made a great choice. Keep in mind that any non-peanut cammed 305 has NO problem running mid 14s.

As to the crane not being an outdated design, one look at the duration @ 0.050 and lift numbers shows me that. It's a virtual clone of the summit special/edelcrock performer cam w/ 204/214, .420/.440. Maybe a *slight* improvment, but nowehere near as aggressive a profile as the comp XE.

But yeah, if your sole goal is to upgrade from a peanut cam while not stepping over the line to have any effects on idle quality or real performance then i am sure the smaller and vastly more conservative crane wins out.

In the immortal words of f-bird 88 though, if you haven't spent a day at the dyno (or track) testing each cam to see what the real change is then you're missing a lot of things that the numbers won't tell you. Seems to me that you are relying solely on an engine simulator to do the dirty work, and not even a good engine simulator at that. As for real world, i've seen more than a few fast 305s running the XE262. The older style mild grind seems to barely outperform factory good cammed cars.

Enough of this for now, i'm going to go play gran tursimo and figure out if the NSX is faster or handles better than a 'vette. (if you catch my drift)

 

You just seem to be in a snit today, Ed.

We value your opinion but have found our own combos that please us. And we've even explained our reasoning.

No need to go around acting somehow superior.

And this quote strikes me as a "Which came first, the chicken or the egg?" type of misunderstanding.

"As to the crane not being an outdated design, one look at the duration @ 0.050 and lift numbers shows me that. It's a virtual clone of the summit special/edelcrock performer cam w/ 204/214, .420/.440. Maybe a *slight* improvment, but nowehere near as aggressive a profile as the comp XE."

If I'm not mistaken, Crane has been grinding cams for much longer than Summit or Edelbrock. If anything, the latter two tend to copy the Crane designs, don't they? I've always been under the impression that Crane and Comp were the two largest cam companies by a long shot. I wouldn't be surprised if Crane grinds the cams for Summit!

 

You're the one with a superiority complex talking about idle quality issues with the XE262 and claiming the the crane is the better overall cam when you haven't run both of them to draw a comparison, nor do you even have a baseline number for your own combo. I'm just pointing out to the crowd that you're not giving the XE a fair shake, and you have absolutely no justification or real world experience to go behind your claims.

I don't care, run whatever cam you want and i'm glad your happy with it. This all started when i pointed out that comp was being ultra conservative in suggesting idle quality / power brake issues and that real world that isn't the case. You took the oppurtunity to act like you had actually run both cams and found the XE262 didn't make power and did have idle problems when in fact you are regurgitating comp's ultra conservative better safe than sorry opinion, and your analysis of power potential is based entirely on a cheap engine simulator program, not dyno or track experience, or even observations from the boards. IMO that is some relevant information for anyone who might be taking advice from you.

And actually, i think crane does grind the 204/214 piece. Doesn't change the fact that it's a nice cam *if* you're building a tow truck. Thirdgen owners are generally after performance, something that grind usually doesn't deliver much of...

 

"I don't care, run whatever cam you want and i'm glad your happy with it."

Ed Maher


Boy oh boy! Were that this were the case!


"You're the one with a superiority complex talking about idle quality issues with the XE262 and claiming the the crane is the better overall cam when you haven't run both of them to draw a comparison, nor do you even have a baseline number for your own combo. I'm just pointing out to the crowd that you're not giving the XE a fair shake, and you have absolutely no justification or real world experience to go behind your claims."

Ed Maher


I will gladly confess that I take a lot of advice into account before I make a decision on these things. As I said before, I took advice from F-Bird'88 (whom you seem to have an axe to grind with), RB83L69, Damon, five7kid, etc. That's a lot more "real world experience" (to quote you) than YOU have!

Are you simply miffed that you weren't included Ed? Speak up when the decision is being made and you will be heard. But stop making things personal when you can't render a successful argument with the facts.

I'm not trying to win over "the crowd" (your words again) because I don't crave a following of any sort. Apparently you do.

I'm just trying to be objective and leave the insults alone.

Why don't you address this argument of facts and figures put forth by F-Bird'88, instead of ruminating over "tow trucks"?

"Ed: You have to keep in mind that Crane hyd cams are measured @.004" for seat duration while Comp cams are
measured at .006". Thus the longer seat duration numbers.
If, a Crane Powermax and a Comp Extreme cam of the same .050" duration are measured at a common lift point for seat duration (say .006") you'll find the Crane comes out on top most of the time ( more intense profile). These are modern fast action Asymetrical grinds that take full advantage of the available lifter diameter while providing smooth valvetrain action for long life.
There is nothing outdated about these designs."

Ed, please direct your intellectual capabilities at answering this.

 

Ok, so I, being completely ignorant, want to know how much of a flow difference (in cfm), at peak torque, and at peak HP, there is between these two cams, if we suppose we try them in Sitting Bull's engine. Would VE of his engine change enough to be noticable?

I'd say not. Also, being completely ignorant, I am thinking that it really doesn't matter what kind of technology is used to achieve the results as long as they are what they are. Mitsu Eclipse allegedly has some of the most modern suspension tech, and new Mustangs with much simpler old-school design still beat it in handling (slalom,etc.). Might be a comparison in the wrong place, sorry if it is.

So, I don't get it... I wouldn't say there would be noticable performance difference between either. I am not a bench-racing freak, but I'd want to know some more arguments...

Doesn't agressive ramp hurt the valvetrain more? How do these cams compare pricewise?

 

The two cams produce virtually indistinguishable hp and torque numbers. So they'd be neck and neck through the quarter, as far as I can see.

I simply want a smoother idle due to climatic conditions, and the fact I have a stock torque converter.

Also, Comp won't recommend the XE 262 for a 305 due to possible vacuum issues on the street and some of the very experienced guys here recommend the Crane 260 for my car.

Who am I to argue?

And it amazes me that these two cams are virtually identical in power, considering their differing specs.

 

What is there to answer about it. So he pointed out that crane measures their seat duration from a different lift point. So what it's relatively shorter in seat duration than the comp than the advertised figures would suggest. What's your point? All that does is say that it might idle a little better. And you're the only person i have ever heard who's chief concern with a cam swap was idle quality, not power output...

But here's my point, see if you can comprehend and address it.

The cam you are in love with is 204/216 @ 0.050 with ONLY 0.427/0.454 lift. Like i said, it's barely bigger than the ancient 204/214 0.420/0.440 grind that i've seen power countless cars to 14 second timeslips, which i (justifiably) consider stock performance. 'Seen' means it's actual performance was measured, so it can be directly compared. And when you run an average 305 with an XE262 you end up with at least a high 13 second car running 100mph or so.

The only thing i am insulting here is your insistence that the crane 260 is superior because you are basing that SOLELY on a cheap, quick and dirty WAG engine simulator program. Maybe i could put a little credence to your 'simulations' if they were coming from a high dollar commercial/professional quality program. Or even better, if you actually had some comparison dyno or track data to show. But you don't. And i do. Ok, so i'm not holding a list of names and timeslips, but i'm not known for benchracing and playing guessing games either.

And you want to know why that peeves me so much. I'm an electrical engineer and spend countless hours simulating deep sub micron digital circuits that fly on radiation hardened ASICs on satelites. And you know what, simulations are only as good as your software and the models you are using. As an engineer, the idea that you can form a definitive answer to a highly complex system like an engine using a $50 piece of software and it's crude approximations that runs in seconds is so STUPID that i can't even pull the punch and not use that word to describe it.

As an example of how STUPID the desktop dyno/dragstrip series of software is (i only have dragstrip, only cuz i got it free) you can make any combo run it's best ET by putting in a converter with a stall speed equal to it's power peak RPM. Thats so far from the truth that once i found that i put the program away and never even touched it again, damn glad i didn't pay for it.

So why don't you address my point that you're a bench racer with junk software. I don't care who you talked to, it doesn't change the fact that that cam is weak and i won't let you put down grinds that WILL AND DO make more power just cuz your STUPID program says otherwise. Like i said, i'm glad you're happy with it. And if somebody else wants to run it too, hey thats fine, it's not my car. But don't go spreading misinformation about idle quality and power potential when truth be told you base that opinion on nothing with substance. I'm not saying the crane won't idle better, but the XE262 is nowhere near a rough cam for a 305 (which is why i posted to this thread at all, i wanted to point out that it is nowhere near causing power brake issues or any other problems that would make it unstreetable.) If you do have some kind of evidence to the contrary, feel free to refute. If you don't have any FACTS to post (and desktop dyno doesn't count) then i'm just gonna let this drop, because i have nothing else to say about the matter.

In conclusion, this isn't personal, and i have no idea where you got the idea that i have something against fbird88, i only mentioned his name because he said exactly what i was getting at, that it's about measured performance, not guessing or anything else. I just don't want people reading this thread to go off buying tiny cams and running lackluster ETs just because some guy who has idle quality above all concerns said that it would make the same power. Because in practice it doesn't. Unless you have some proof otherwise?

 

Damn thats long, thought i better make cliff notes.

- The crane 260 will idle better than a XE 262
- The comp XE262 is very streetable and will have no vacuum issues. And thus, unless a perfect idle is your main concern you shouldn't rule out this cam

- Desktop dyno is fun to play with and get a rough idea on how something will work, but it is far from accurate enough to form a definitive answer on power production. Arguing with DD results is bench racing in it's purest form.

- And finally, in the real world, the XE262 outperforms the crane 260 or similar small cams.

Unless you can show me proof to refute the final statement i consider myself satisfied. To show good faith for proof, look at Bort62s LG4 for an idea of the XE262s potential. He's gone 98mph with stock LG4 exhaust manifolds and cat, stock heads, and also running some **** poor gear like 2.73 or 3.08 in southern california heat. Find me a car running better than that with similar handicaps on the crane and i'll believe you have a point. Hell, even with headers and decent gearing in good air find me a crane 260 car running 98mph and i'll give you half credit.

 

OK, here is the other program F-Bird'88 ran the cams through, and here is what he told me. It is on the record here on thirdgen Tech/General Engine, dated July 4, 2002. This was comparing the Crane 260 to the Crane 266, which is their build to compete against the XE 256 (which is a kissing cousin to the 262 spec and power wise). We were also keeping in mind a set of heads with pressed in rocker studs and thus were deliberately keeping our choices in the .450 lift range.

To compare the cam Crane INTENDS to be compared to the XE 262 you would have to run it against the Crane PowerMax 272. You can see how they use grind numbers to suggest superiority. In any event, according to Crane they beat the XE 262 by 10 hp and 10 ft. lbs. of torque.
______________________
I ran both cams and a few others through a little more suffisticated program than Desk Top Dyno.
(Performance Trends Engine Analyser)

The crane powermax 266 was the better of the two
in both torque and hp.

The stock heads really hold back these cams potential
I got 263 hp with the stock heads and 315 with "my ported
305" heads.

Please note that because of "my ported heads" larger
port volume, There was a small loss of torque below
2500 rpm. This is typical of ported heads on small motors.
Some benefit could be realized by epoxying up the floor on these heads to both improve flow and increase volosity.
A torque converter with a actual stall of 2800/3000
behind a 305 is called for / for max performance. The converter should be swapped for the "corvette/ s10 converter" as a minimum. If you're stuck with a tight (1400stall) factory converter
a smaller cam may be the wiser choise overall. like crane's H260-HMV
These cams also responded to increased compression ratio
over the stock factory motor. The available octane gas
would be the limiting factor.

Also note that I modeled your 305 using SAE net "As installed"
conditions using your exhaust system specs, to better simulate real world in the car results.
Dyno 2000 can't do this.
So based on this simulation, The crane cam was a clear winner
over all and the motor is crying for better heads and a little more compression..

In my experience, Both these companies' products are real good.
Both companies have there fair share of failures especially when customers "pop a lil' cam" in a used motor. I include my self here.
The culprit is bad lifter bores. Either glazed or scored.
If the lifter cannot spin freely in the bore while running, the
cam (anybrand) will fail. A small brake hone, quickly run through
the lifter bores to clean ,em up during a cam swap makes all the difference in the world.

Dyno 2000 always assumes a perfect exhaust design.
So choosing "Small tube headers and mufflers" may not best model *your* small tube headers. According to the instructions, your shorty headers are better modeled by choosing "high perf manifolds and mufflers." You get a more realistic result. Try it.
The truth, typically falls some-where in the middle. I like
to interpolate between the two choices here.


Last edited by F-BIRD'88 on 07-03-2002 at 02:46 AM
_______________
I estimate that with your 305 tweeked to true 9.9cr
with the above mods, a good 9.5 in 3000 stall converter
3.73's and short sticky tires like BFG's P225/50/15 drag radials
you should run 14.10@97 with stock 305 heads and
13.65@102 with my fully ported 305 heads.

F-Bird'88
________________

quote:
--------------------------------------------------------------------------------
Originally posted by Sitting Bull
Russel,

Does your dyno program show the Crane 266 with an advantage in torque and hp all through the rpm range, or just above 4000 rpm, or where might it be?
--------------------------------------------------------------------------------

In this simulation the Crane 266 had a clear advantage
all the way through. Except below 2500rpm. The comp cam was designed for a 350 with its 110* LCA.

If I was stuck with a 1400s tall and 2.73's I'd probabily select a smaller cam either way. The loss of torque near 2500
is too important because you spent so much time at or near there while driveing with that set up.
Even the factory 305HO with a 203/207-.404/.415 on 115 LCA
used a special 3000 converter and high gear in the monte SS.

The simulation slowed to 14.85@100 with the 1400stall/2.73's
on the ported head motor. Sorry
Maybe you could ask for members to post there real world car with simular mods and real timeslips and see what to expect.

It seems that the rear gear/ converter/compression ratio
mods are real critical when you put a longer duration cam in a 305.
This is typical of small motors. I remember when a friend put a Comp cams 260H high energy cam 212/212-.440" 110
in an other wise stock 267. It was a dog. Lots of rpm but no
torque.


Last edited by F-BIRD'88 on 07-03-2002 at 01:12 PM
_________________

That was our reasoning process and as you can see it didn't just rely on that "STUPID" DD2000.

So my advice stands. On a daily driven car with a stock torque converter, the Crane 260 should be your choice. (And as you can see by my sig, I am also using a nicely ported and polished set of heads, too.)

If you are building a weekend dragster that doesn't have to cart you around in a severe climate, like Virginia, then go crazy.

And I should point out, since you missed it at the beginning, this thread is dealing with a Canadian climate.

As for vacuum issues, I merely repeated what the manufacturer of the piece advised me. All in all, I must take Comp's own advice over your's.

 

OK, 1 more question, b/c I want to know how streetable XE262 is... (originally, I was planning to go for XE262, but now I'm not so sure)...
What's the torque output in 700-2000 RPM powerband for XE262? (approximately)
What is it for Crane?

I didn't see it in the graphs above...

I am planning on my car being a powerful street car, not an all out dragmaster. But I do want a street car that will eventually do low 14s (realistically) - high 13s (ideally)... and I don't want to lose much on the bottom end...

I am programming a custom FI for it, based on Megasquirt from diy-efi... so idle should be OK in both..

I am just a beginner and, here, fill me in on this if you can...

and, again, what's the pricing for both?

btw, I still can't read the cam specs completely, but it seems Comp. has a higher lift.. now, for me, that means significantly more air... higher lift on similar duration means more air..hm. i'm repeating myself..

What stall does a stock '92 700R4 TC have?

 

If you are using a stock 1400 rpm stall torque converter--which is what a 700r4 has--then you will want to be conservative in your cam choice. This would indicate the Crane PM 260 or even 266. (The alternatives are the Comp XE 250 and 256.) This is especially true if you want to have a daily driver and have a tough winter climate.

There is only a $10 difference between the two brands.

None of the programs seem to provide info below 2000 rpm, but an aftermarket cam is bound to have poorer torque and hp than the short duration and low lift GM cams.

So I can only tell you that Comp does NOT recommend the XE 262 for a 305. That's what they told me on their toll free phone line. Thus I can only observe that Comp ought to know more about their own cams than Ed Maher does.

But maybe they don't, eh? Ed says they are too conservative.

Yet I must ALSO observe that a 92 305 uses a roller cam, which renders this argument almost irrelevent for you.

 

now, "roller" would have something to do with types of rocker arms in use, right? not too familiar with OHV-specific parts.. could someone care to explain and fill me in?

 

Your car, like every small block Chev since 1987, uses a roller cam and roller lifters. They are completely different from the flat tappet hydraulic lifter cams we've been discussing.

 

Streetability is a subjective thing.
The Xe262 is a fairly big street cam on a near stock 305.
Low end torque at or below 2500 rpm will be less than stock.
To get the benefit of the Xe262's longer cam timing you would
want better flowing heads like Vortecs, higher compression ratio
like a true 9.8 to 10:1. A high stall converter 3000 rpm minium
and high rear gears. A RPM style intake and 750 cfm carb. Free flowing headers and exhaust.
If you just install this cam in a stock 305 without the other matching component of the system you're in for a letdown.
In that case you'd be better off and much happier with a milder cam like the Xe250 or the Crane PM260.

One of the biggest mistakes (and the most common) in modifying and building motors is selecting a cam that is too big for the job.

 

One thing I did not see mention was how any of these cams affect emissions. Will say, the smaller PM260 been more emissions sniffer friendly then the bigger XE262??

 

I suppose it would, if it is carb based. FI might be able to lean it down to a non-issue.

I don't have to worry about this in Alberta.