TreDeClaw

My engine is a two bolt main built bottom up wondering what cam/heads to put on.

I am planning to take out the motor which would be a great time to do a cam/heads swap because I was not really impressed with the power of the 69 corvette cam (.447 int. exh. .050 dur) and its double hump heads.

Not looking to spend to much money on heads, a buddy has some vortec heads sitting around and I thought they might be of interest. I look up the specs and although they have been said to be "much better" they seem to be the same.
Double hump: 202 intakes and 160 exhaust valves and had a 62cc combustion chambers.
Vortec: Combustion Chamber Volume: 64 cc 194 intakes and 150 exhaust
And I believe I would have to buy a new intake? (I have an edelbrock RPM air gap intake)

And what cam would go good with my choice of heads, intake, etc. (currently .447 in and exh. .050 duration.)

Orr89RocZ

iTrader: (20)

Vortecs are much better than old heads. Valve and chamber alone do not tell the story. Do them with a good vortec dual plane and step up to a modern cam, something in the 268 deg advertised range and it will haul

truckerz

iTrader: (2)

What he said. Orr knows his stuff. Seriously. With Vortecs and something like a 268 cam you will be quite impressed. It will be punchy and have good drive ability.

If you don't want to go the vortec route, grab up a set of profiler 185 or 195s for like a grand. Grab a 268 cam (the lift on comps grind is like .571 or something like that with 1.6 rockers) for 150-300 bucks and get a nice used dual plane, and have a blast.

I'm doing something similar with a roller motor, and I can't wait. It has been done before and people seem to get great results, it is a proven combo. Since I have a stock bottom end and a very shallow wallet I opted for the 185s. I'll never see over 6k, and I don't anticipate me having another bunch of cash to throw at another project, or better this one, and forged goodies were too expensive.....so take Orrs advise. Your car will come ALIVE, weather you go for the vortec/268 vortec base, or the profiler/268/standard chevy base.

sofakingdom

iTrader: (1)

Main problem with your combo, was that crappy old cam. That worthless thing has been disappointing hot-rodders for over 3 generations now; yet somehow people just keep on falling for it. Sorry your intro to hot-rodding was ... that. Best favor you could do yourself RIGHT NOW, is throw that in the trash where it already belonged 50 years ago.

2-bolt main is a non-issue. Don't let that bother you in any way.

The Vortecs are unquestionably "better" heads than the double-humps. How much better, for whatever you're trying to do, is not so clear-cut. Orr is absolutely correct, the particular "specs" you listed are just the barest beginning of understanding what makes heads work. And yes, a new intake would be required.

The later-model double-humps, with the bolt holes in the end, are MUCH better than the earlier ones. If those are what you have, then you might be able to make an UNBELIEVABLE difference just by putting a common-sensical cam in there.

You don't mention what exhaust you have. If you still have ANY PIECE WHATSEOVER of your original LG4 stuff on it, or anything that is AT ALL compatible with it, then that also needs to go in the trash. Every single piece, no exceptions, heads to bumper. Get a set of headers specific to this chassis, BUT NOT FOR LG4; something like for a 88 350 TPI would be more appropriate, with a 3" ball-flange outlet. Get them ceramic-coated, get a new 3" high-flow cat, and a 3" cat-back of your choice. I highly recommend the Hooker. If you can't find headers with the ball flange, get ones with the old stooopid no-workie always-leeeeekie 3-bolt flange (another thing that has been a disappointment since the 60s that I know of, and yet people continue to shell out good money for that garbage) and cut that off and put ball flanges on em before ceramic coating.

Another thing that will make A WORLD of difference, is a good torque converter. Must be driven to be believed. Just allowing the engine RPM to get above 1400 at launch will make it feel like you just bolted a rocket motor to your roof.

TreDeClaw

I left out the part of my 305 manifolds and stock exhaust because I know you all would not give me correct information on what I would like to do with my engine and tell me "headers all the way back dummie".
Just got a brand new transmission, came with a free 1650 stall. I would really like one that summit sells $300 2200 holeshot converter.

So another question then, if I decided to keep my heads http://www.crankshaftcoalition.com/w...NQVAQkDJmZ.jpg which looks like those ones on the right, (I believe those are the ones with bolt holes you are talking about) then what is a good cam choice for those heads?

-- Thanks everybody.

Orr89RocZ

iTrader: (20)

I'd still do a modern lobe cam in the mid 260's duration advertised range. Something 218-224 at .050 aint shabby for a streetable 350.
Goes without question, need headers/exhaust and 2200 stall you were thinking about would be a great addition

MustangBeater20

I have vortec heads and the LT4 hotcam. I love it! And yes, the vortecs need a special intake manifold.

TreDeClaw

Im looking for a flat tappet cam? I am viewing some comp cams on summit racing.

http://www.summitracing.com/parts/cc...make/chevrolet

http://www.summitracing.com/parts/cc...make/chevrolet

My cam .050 duration is at 223 int. 223 exh. already.

Orr89RocZ

iTrader: (20)

Yes hyd flat. I believe you have the gm 3896962 L-82 cam?
Its the 312/312 advertised duration and 222/222 at .050" duration 114 lsa grind. Junk

Way to much duration which bleeds off low end cyl pressure. Lazy ramp. Slow valve motion low power. Modern comp xe268 or lunati voodoo would be like 268 deg advertised and 224 deg at .050 on a 110 lsa. Much faster valve motion, much better cyl fill across the midrange and better idle. Could go xe274 for more top end but those heads are already maxed with a 268 cam imo

DeltaElite121

Solid flat tappet, or go to hydraulic roller. Hydraulic flat tappets are the biggest waste of money this hobby has to offer.

redneckjoe

dang, some great advise in here.

don't be afraid of picking out a higher stall converter.

BASSETT IROC 85

iTrader: (2)

I have ran both the cams you listed and they perform great. I agree on vortec heads they are night and day better than your old heads. If you cant find a Used Performer vortec manifold they are some chinese copies that work good and can be found around $100.00.

TreDeClaw

The cams I showed or Orr?

I just don't wanna spend much on an intake, i just bought mine.

BASSETT IROC 85

iTrader: (2)

I would buy intakes all day to gain the power that you will make with vortec heads. You could sell or trade yours.

Lurbie

iTrader: (3)

Ignore my statement about modifying it. It's wrong, keep reading.

You'll always be able to sell that intake if you wanted, it's a great one. Someone will surely correct me if I am wrong, but I think you could simply change the angle of the intake holes and still use your current intake as well. I do believe some companies already sell dual fit intakes and that's what they've done is just slot the bolt holes to handle either bolt pattern.

sofakingdom

iTrader: (1)

Ummmm.... no.

Yes, they do indeed; not because it's A Good Idea, but rather, because there are people who are enough of a sucker to get scammed that way, and also, people low-life enough to SODOMIZE them.

Here's what an intake that fits old heads looks like attempted to bolt to Vortec heads:



Whaddya think?

While it would be "possible" to manufacture an intake tha twould would have both sets of bolt holes and maybe actually even COVER the ports on both styles of heads, the fact that they would fit the old ones AT ALL, would mean that the roof of the port would have to be so low as to largely negate the benefit of Vortecs in the first place.

The thing that makes Vortec heads superior to the older ones, is that the intake port is in a different place; about ¼" up higher, giving a straighter shot at the intake valve. As a result you get MUCH better flow without the penalty of a larger port; IOW velocity, as critical a component to an engine's overall performance, stays high.

No Orr, the cam he has is the "151"; the "375 HP 327" cam. What a steaming pile of horse exhaust. It's actually .447" lift on both sides, 222° @ .050" on both, advertised duration is approximately FOREVER AND A HALF. Just an altogether TERRIBLE cam. Such a shame that people get snookered by all that "375 HP" and "64 Vette Stingray" and all that other crap.

MustangBeater20

You're in the wrong hobby if you're not willing to spend the money! You might as well do it right the first time.

Lurbie

iTrader: (3)

See, I knew someone would correct me if I was wrong.

Thanks sofakingdom, I had not looked into it enough to realize how far off the runners were, that's crazy and you're right; that would suck to try to make that work. Definitely wouldn't try that now. I'm glad you shared the pic, really shows how bad of an idea that would be!

TreDeClaw

Can someone link me to a summit racing or jegs vortec intake? I cant seem to find one to price range or anything.

Do I need to change lifters/rockers/pushrods or anything from these heads to vortec? Is anything going to hit?

Orr89RocZ

iTrader: (20)

Vortecs used self aligning rockers. But you can get them setup for guideplates and regular rockers. Think the current heads you have are non self aligning

redneckjoe

wont those vortecs need work for a high lift cam? i thought max lift in stock form was about .450 before you get clearance issues? just thought i'd toss that out there.

BASSETT IROC 85

iTrader: (2)

You are right they will need work to run a cam over .450 lift

Orr89RocZ

iTrader: (20)

Beehive kit should give .500-.520". Or shave down the retainers on conventional springs. Alex's Parts sells a spring kit that will do over .550" no mods needed. Guy here on this board did that to his big cammed stock vortec head motor and he ran high 11's

BASSETT IROC 85

iTrader: (2)

http://www.jegs.com/i/Weiand/925/8121/10002/-1
http://www.jegs.com/i/Speedmaster/74....1006/10002/-1
http://www.jegs.com/i/JEGS+Performan...13002/10002/-1
http://www.jegs.com/i/Professional+P...52007/10002/-1

TreDeClaw

I have stock LT1 springs on my double humps right now. Will they transfer to vortec and would I need to buy aftermarket like the set from alex's parts?

jokerZ71

1st you should pick a cam & then use springs w/ proper specs(seat/open psi,clearance)that the cam mfr recommends.Vortecs can generally be fine with a .470 lift.This should be verified tho.GM uses 1.6 rockers on the Ramjet 350 for .480 lift using stock L31/Vortec springs & retainers.Total seal to retainer clearance is fairly consistant to run .520 to .530.This allows for a .470 to .480 lift cam & a recommended .050" safety clearance.AGAIN THO,this needs to be verified with any cam.Vortecs are an easy 40 HP gain over your Double Humps.

TreDeClaw

So I E-Mailed Comp Cams with the Setup I will have and they suggested a cam that is WAY bigger then what you guys suggested on here. So is he completely wrong?
Here is the link to the part, and below is the email. http://www.summitracing.com/parts/cca-12-326-4

Night rider327

iTrader: (13)

Yes the vortec heads are that much better than the old double hump heads. Look for a good 35-40 HP gain just from the vortec heads. The valve size and chamber size has very little to do with a head's over all performance. What counts is the port size, shape, design, etc.

The double hump heads flows 214 to 220 cfm on intake side and 137 to 142 cfm on exhaust side depending on which version you have or look at.

The stock vortec heads flows 239 cfm on intake side and 162 cfm on exhaust side.

Which you can see the big diffanace in flow rates but there is more to the story though... Those numbers are peak and at the highest limit the head flows good at.
For the double hump that is .600" lift
For the vortec that is .500" lift

But the even better thing is the vortec's low lift numbers. The valve is only at peak lift once while it's at all the other points twice, so looking at the low lift numbers means alot too.

Like say .300" lift
Vortec flows 190 cfm intake / 137 cfm exhaust
Double hump flows 167 cfm intake / 119 cfm exhaust.

The cam comp said to use is ALL wrong for this combo. The vortec heads likes 8-12* more exhaust duration than intake, also likes more exhaust lift than intake.

I'm not a fan of comp cams camshafts or tech advise.

For the perfect cam, I would need to know your true compression ratio to pick the best cam, but as a gen. idea for a street car that just wants good power to play, redlight to redlight and maybe a few times a year at the track. I would say a hyd. flat tappet cam in the 214 to 218 degree intake @ .050" / 224 to 230 exhaust @ .050" with a 112 LSA

Lift will be in the .443" to .453" intake / .465" to .488" exhaust.

Theres alot more to cam profiles than just the above numbers. It's the shape of the lobe, how fast it moves the valves. The old cams like the one you have now has high adv. duration with pretty mild duration at .050" and mild lift. This is a slow ramp or lobe.

The newer cam grinds will have MUCH less adv. duration for the same amount of duration at .050" and also more lift. These cams have faster ramp speed, moves the valves much sooner.

For intakes.. Here you go
http://www.summitracing.com/search/p...keyword=vortec

Out of that list I would recommed one of these depending on compression and which cam you went with
SUM-226018 $144
SUM-226019 $203
PFS-52007 $155
PFS-52028 $176
EDL-2116 $200
EDL-7116 $215

Or of course you could look for a used one on here or on your local CL

You need headers and good aftermarket exhaust. All of this is for nothing with out the exhaust. I would guess to say your leaving 30 HP on the table right now with your stock exhaust. IMHO headers and good exhaust should be the very 1st engine/power mod that a person does on one of these cars.

Do the vortec heads, morden cam profile in the size I listed, add headers and good exhaust, and I wouldn't be scared to say you will gain 75-80 HP.

Back that with a 2400-2800 rpm stall torque converter and 3.42 gears and you will have a killer street car

cuisinartvette

Which casting # is this?

The ones Ive flowed never went over low 220s intake stock usually 2teens
Ex around the 150ish area

Night rider327

iTrader: (13)

That was a set of 062 heads from a 1997 1/2 ton pickup

TreDeClaw

These are the cams I am looking at. Which cam looks best for my combo?

1. http://www.summitracing.com/parts/cc...make/chevrolet
2. http://www.summitracing.com/parts/cca-cl12-601-4
3. http://www.summitracing.com/parts/cc...make/chevrolet

Night rider327

iTrader: (13)

The thumper cam is too big. In fact all of the "thumper" cams are a joke. They are more for sound than real performance.

The other two looks good except for the LSA. The 114 LSA is alittle too wide. 112 would be best.

Again what's your compression? The cam must be matched to the compression.

If you don't know your compression list your parts and we can try to figure it out.

Need to know bore size, stroke (3.48), piston style and CC (a part # would work to find the info), head gasket bore and thickness (part number can be used again to get that info) , deck height, how far piston is down in the bore at TDC, head chamber size (if your going with vortec heads they I have that info)

TreDeClaw

In one of my recent posts it says some of the information on compression. Ita either 10 or 10.5:1

Night rider327

iTrader: (13)

Yeah I seen your post that you sent to comp cams with your engine/car specs.

Nothing against you, don't take it the wrong way, but I always try to get people to tell me how they came up with X compression. Alot of things goes into the mix and not everyone knows details like some of the things that you need to know to get compression.

So I try to get all the part #'s and specs on block so I can figure up compression and know for sure what the real # is.

Even with your's. Something looks off from the specs I have for it to be a 10.5:1 engine. I see you said 64cc heads. So unless you have dome pistons, I don't see it being 10.5:1
Most flat tops are in the 5 to 8cc range.
About the highest would be 10.43 and that's using a .015" thick, 4.100" bore gasket, and 5cc flat tops, with an 8cc flat top that would be 10.08:1

Add a common blue fel pro .041" thick x 4.166" gasket and your at 9.46:1

Case in point. A friend of a friend said he had 12:1 on his 327. I asked what dome pistons are you running. He said no they are flat tops. No way to get 12:1 unless your running 50cc head (he wasnt). He had some numbers switched around and what not. Ended up with 10.4 or so with his 58cc heads

TreDeClaw

Looks like I have flat top pistons. They have valve release (whatever that is) but that's what I see when comparing the look of my piston to others online.

jokerZ71

Be sure you're not seeing dish pistons.A lot of ppl confuse the dish with flat tops.Flat tops will be completely flat on top except for either 2 or 4 half moon shaped indentions.(valve reliefs)A dish piston will have a slightly raised band around the outside edge of the piston top along with the valve reliefs.

TreDeClaw

They have half moons. they are flat.