well i got all the accessories off the front of the motor. i am going to pick up a puller to remove the balancer, then drop the oil pan a little to get off the timing cover, once thats off, how can i get the timing chain off? can i undo the cam bolts and it will become loose? once i take out the camshaft slowly and turning not to nick cambearing, how should i put in the new one? the same way the old one was? how can i be sure its going in right? also when thats in, i put in the bolts for the camshaft, do i torque them? how do i put on the timing chain? both of them line up at 12 oclock right? is there anything else i should know? how do the lifters come out? just unscrew? my motor is a 72 350 with flat tops, and its hydraulic flat tappet camshaft. i picked up an edelbrock 7201 RPM camshaft .488/.510 for a good deal i wanna replace my .454/.454 small cam, plus im running 1.6 comp cam pro magnum rockers. i sold my trick flows and got edelbrock rpm heads, and im running edelbrock rpm air gap intake. just need some tips to make sure this goes smoothly!! thanks alot in advance.

Once you have the timing cover off you will unbolt the three bolts that hold the cam gear in place. At that point the chain and cam gear will slide off. The crank gear will remain and you will need a gear puller to slide off the crank sprocket gear off of the crank.


You will slide the cam in just like the old one cam out. Once it is in you can allign it (it will spin) with the timing chain.

They just slide out once you remove the valvetrain.

Refer to this thread for some cam swap info. This is for a roller motor so not everything will be the same. However, cam allingment and timing chain info will be roughly the same. You can skip all the cam history and explanation and go right to the installation part.

Cam swap article

ok so i slide the cam out, without taking out the lifters and they wont fall into the block?

does the cam gear have to come off to take the camshaft out?

do i have to put the timing chain on a certain way or will it only go on one way? once the timing chain is on there are dots on both gears and should both line up with 12 oclock i assume.

and this is all with #1 cylinder at TDC

Lifters have to come out.

Timing gear has to come off.

There is a dowel pin that locates the timing gear specifically.

Did you read the cam swap article yet?

the lifters come out first. They're under the intake.

The cam gear must come off in order to get the cam out.

And you must line everything back up to time the cam in.


Have you considered having a shop do this?

i meant the crank gear not the cam gear, but in the cam article his hasnt, my timing chain is less then a year old.

oh its just he said once the camshaft comes out the lifters just fall out, but im assuming the lifters come out first, how hard is it for them to come out?

it looks pretty straight forward expcet in the pic he has the cam gear at 6 oclock, and the crank gear at 12 oclock, so the dots are line up close together, which way was is it suppose to be done?

shop's charge too much and i think this isnt that hard of a job, just make sure everything is lined up.

put the cam same way it came out, does the cam gear only go on one way or should i watch where the dot was when it came off to put it on the same way it came off?

you should line up the dots before you take it apart. The ideal way would be to degree it in and either install a hex-a-just timing set of install a bushing, but I doubt you'll do that. Take the intake, valve covers, rocker arms and pushrods out. Then the lifters will slide out. Line up the two dots on the timing chain and remove the big gear. Then replace the cam and put it all back together the way it came apart.

Why are you swapping cams?

It doesn't matter how old your timing set is - unless you're needing to be really cheap. Replace it - that means both the crank and the cam sprockets come off.

I rotated the cam, via the sprocket, so each lifter popped up then grabbed the top of them and pull them out. They just slide out. Once all 16 are out, the cam can come out.

I installed mine dot to dot (the 6 and 12 configuration). and then made the corresponding rotor terminal go to the #6 cylinder.

Before you do anything, bring the engine around to #1 TDC. It makes things a lot easier when you have to line everything back up.

This sounds like a mess in the making...

Yes, yes it does.

You might want to start researching how to install the distributor and set the ignition timing properly as well as how to adjust the valves before you get yourself in a bind.

Sounds like you already have a pretty good cam in the engine...

Do you really think that the new cam is going to be that much better?

What are the lift, duration, and LSA specs on each of the two cams?

That's a lot of work for what I suspect will be very little performance gain....

Get a degree wheel and confirm it when you are done installing it.
I bought the summit kit for $70 some bucks and proved worth it when I inadvertantly set it up off by a tooth because I didn't shorten the pin enough (LT1 cam in L98). Thought for sure i did it right only to find I oops' it somewhere . Now that I see how it all works with the wheel, its easy to confirm exactly what you have and the exact advance I wanted.

why is this a mess in the making. i know how to drop in a distributor and set the timing? you guys are making me look like im an idiot here. and i know how to set the valves i got the sheet to set which valves on the intake/exhaust on #1 or # 6 TDC.

the motor will be at TDC # 1, and i will set the dots to 12 and 6 so they are lined up together.

my camshaft now is a crane energizer 216/216 duration .454/.454 1600-5400 is what i have installed now. with the 1.6 rockers it will give me .486/.486 lift

the camshaft im going to is 234/244 duration .488/.510 112 lobe separation. with 1.6 rockers it will be .520/.542

your telling me i wont see any power gains going to this camshaft? i should stick with the one installed, it just seems like a small camshaft for the rest of my motor and other people on this board feel the same way.

i got a 350 .30 over, flat top pistons, edelbrock performer rpm heads, comp cams 1.6 pro magnum rockers, edelbrock rpm air gap intake, edelbrock 750cfm carb, march pulleys, headers 2 1/2" exhaust

i just thought this camshaft would match the motor since its part of the edelbrock power package to give me roughly 420HP or a little more. maybe i should go with a diff camshaft or stick with mine, shed some light as i know the basics here and have a friend that cam help me out that did a camshaft swap on his motor.

Read your first posts?

That's one of the few reasons why. You need to be at 12 and 12 for TDC #1 firing. 12 and 6 is #6 firing.

There are 2 instances of #1 TDC in a complete engine cycle. Only one is #1 firing.

#1 TDC w/crank dot at 12:00 and cam dot at 6:00 = #6 firing

#1 TDC with both dots at 12:00 = #1 firing

It's easier by far to line it up at the #6 firing spot, then turn the crank one full turn (which turns the cam 1/2 turn) to get to #1 firing, and drop the dist in.

You'll hate that cam. You'll see. Power as such won't be the issue. What WILL be the issue, is the low vacuum, horrible fuel consumption, and all the other "big cam" behaviors that go with over-camming an engine. Except it won't really be over-cammed, it will just act like it. You can get just as much power, IF NOT MORE, without all the "big cam" problems you are about to enjoy, if you run a more modern cam. That cam design is close to 40 years old now. We've learned a thing or 2 as a species about cams and how to design them during the last few decades. Take advantage of it.

As a side note: there's a reason you got that cam "for a good deal"; and it ISN'T because people that know what they're doing, are lining up in droves bidding up the price just to have a chance at getting it.

You'll find that the thing that will cause you to hate it, namely the EXTREMELY LONG LAZY ramps, will also make the valve adjustment method you described, which is the "Chilton's" method for little weenie stock cams, is useless with that cam; because about half of the cam lobes will be somewhat off their base circle at those points. So your valve adjustment will be loose and incosistent.

Instead, use the EOIC method. Which is: adjust each cylinder's valves, one at a time; turn the motor until the cyl you want to adjust has its exhaust valve just barely beginning to open; adjust that one cyl's intake at that point; go through the firing order one cyl at a time, and do each intake valve one at a time. Then watch for an intake to be just closing after passing through its peak lift, and adjust that cyl's exhaust valve, and go through the firing order and adjust them each that way, one exhaust valve at a time. Set them to where you just barely take up all the free play in the push rod between the lifter and the rocker, WITHOUT DEPRESSING THE LIFTER PLUNGER; then add a suitable amount of lifter preload, which would typically be 1/4 to 1/2 turn.

well i wont use that cam if it sucks, ill pick up another one? any suggestions

is it worth putting in a biger camshaft with my setup i was told yes

Basically that cam has too much duration.

220/230 or even a bit less is about what you should be looking for. Lifts of .510/.520 with 1.6 rockers should be fine as well. LSA should typically be 112 deg., though lots of folks use 110 deg.

Bigger cam than what you have now?

Maybe.


The "RPM" cam? or perhaps this one ? (I hope your "good deal" was better than this price....)

Not necessarily.


Look at the Comp XE274; or the new Voodoo series from Lunati. Look at stuff with .050" durations in the same general ballpark as that Neanderthal thing from the Stone Age; i.e. in the 230 - 235 degree range on the intake.

Look how the XE274 has "advertised" duration of 274 degrees, and .050" duration of 230 degrees. That's 44 degrees that the valve spends getting from near zero to .050", and back; in other words, just barely cracked open.

Now look at the Stone Age generic cam out of the overpriced Edelbrock box. 292 degrees advertised, 234 degrees at .050". That's 58 degrees with the valve barely cracked open.

The .050" duration, which is what mostly determines the power, is only 4 degrees different; not much at all.

That means they'll make roughly similar power, with roughly similar torque vs RPM curves.

But: the advertised duration, i.e. seat timing, is 274 degrees vs. 292 degrees.

Which one do you think is going to "act" more like a "big cam"? In other words, which one will use more gas, give less idle vacuum, be harder to get a carb set up for, require more effort in a general way to get to behave?

yeah but with #1TDC and 12 and 6 i can drop the dizzy in pointing to #6 and it will fire.

thanks sofakingdom, i was actually looking at the xe274 also, maybe ill change my decision.

with my setup what do you think would be "too big" a cam?

No, not too much, I think it's about right.

The RPM heads have 170cc chambers. They're specifically designed as a STREET head, NOT a dyno queen or race head. They don't have gigantic flow numbers like 220cc Canfields or Brodix Track 1s or something. Consequently they don't put up huge HP numbers, or run up beyond 6500 RPM or so no matter what other parts are around them, even on a little motor like a 350. They're set up to make good torque in the midrange, and a decent if unexceptional top end on the scale of a STREET motor. They do what they're designed to do very well.

Therefore, pick a cam that goes along with what the heads want. Which is, good power from 2500-5500 RPM. Under-camming would basically be a waste of the heads' capabilities; over-camming would move the rest of the engine's curve out of the optimum range of the heads. You want everything to match, and work together. A cam that peaks at about 5500 RPM is the perfect match for those heads.

MAKE SURE you get the "upgrade" valve spring package on your heads. The "base model" package is very little more than stock GM, adequate for a lazy cam with slow valve action like the RPM cam; but will be totally overwhelmed by a cam with "modern" ramps. You will risk having problems ranging from valve float, to broken springs or other parts, to wiped cam lobes. The huge majority of the time, when you see people having valve train problems, the root cause is, NOT ENOUGH VALVE SPRING.

ok well im not making this motor for a 10 second car or anything, just something with some power, and i want to upgrade the small camshaft to something a little bigger, which the xe274 is. im only hopin this motor is capable of 12 seconds.

i tried to look up what the springs can handle but i couldnt see, i would think they would be capable of at least a .540 lift dont you think, with 1.6 rr's i wouldnt be pushing .522, but i need springs i will get them, save trouble in the long run

also i see a xe274 on ebay in canada actually says is brand new, no lifters, i cant re-use my lifters right, which kind should i get, or shold i just get the package new with cam and lifters.

the 274xe calls for stock diameter 981-16 springs,these springs are the limit of stock style(tube shaped) & diameter(1.250") valve springs that can be used on the street.they have a max lift of .490.
the isky and crane tool room springs are awesome,but don't expect to get street miles out of them.they can handle about .600 lift.

"my oppinion"
if you decide on the 274xe(my favorite all around hydraulic cam ) .
stick with 1.5:1 stock or comp roller tip rockers and the 981-16 springs.
or get the valve seats machined to accept1.43" diameter valve springs and use either the 986-16 or the 9887-16 set and limit your rpm accordingly.
the one thing about the comp. "XE" series is they have verry aggressive ramps!
if you end up with the 1.25" springs,try to find some stock springs to beak the motor in with.
if you go go to the double spring (986-16 or 987-16) be sure to break the cam in using only the outer spring .be sure to keep the break-in revs between 1800 and 2500 for the break in period and vary the rpm constantly.
remember to prime the oiling sytem !use an old distributor with the advance mechanisim removed,
or sprend the $ for a pre oiler.
if you have a problem with air pockets in the cooling system causing a boil over,or timing adjustments causing a stall or a shutdown,don't panic.just check everything over for a sec and fire it back up!mine took 5 trys,and the cam still looks like new after 3000 HARD miles and 4 valve tip failures!(due to incorrect retainer to guide clearance or coil bind.oops!
if you use stock springs to break this cam in,DO NOT USE THE OIL DRIPPERS that sit between the retainer and spring!they reduce the coil bind of the valve spring to a dangerous tolerance.
also DOUBLE CHECK THE RETAINER TO VALVE GUIDE CLEARANCE!
if you set up your motor correctly, you will LOVE THIS CAM!
Eric B

if the cam is used do you still have to break it in, im not saying im gonna get one, but if i do, its better just to buy these new right.

don't ever consider a used hydraulic flat tappet cam. don't even look directly at it.


the lunati 60104 is pretty comparable to the compxe274, if you're still doing some soul searching.

lunati's 73943 springs are also pretty sweet, they're comparable to the comp 986's, but in the 1.25 (comp 981) size.

isky and crane "tool room springs"?? i've never heard of that, what are those?

I must have missed it above,,, what cyl heads have you decided on or have now for your 350RWHp engine project?

I dont know that I would go that far. If it was my cam, not a used one Ibought, i would consider using it. If I broke it in, and i used it for a short period of time, it wouldnt worry me at all. I wouldn't pay money for a used flat tappet though.

yeah alright ill look for a new camshaft, they said the xe274 would be my best choice, i have 1.6 rr's also.

the heads i have are edelbrock performer rpm heads, i got them new, they are not on the motor yet, i was wondering, would these give me 350rwp with the rest of the motor, could i port them? would it hurt to make them 62cc or more instead of 64cc?

im actually just needing a camshaft to work great with mysetup and so far it looks like the xe274

350 .30 over, flat top pistons, edelbrock rpm air gap, edelbrock 75cfm, 1.6 pro magnum rockers, 1 5/8 headers 2 1/2" exhaust.

700r4 built, 410 posi, just looking for 12's.

Well, I am not an engine expert, but it was said above that those heads have 170cc intake runners. That seems small for 350RWHp. I would expect that 190cc intake runners size would be the minimum for 350RWHp.

ok i might get them ported then to 180-190cc. but other then that, would the xe274 do it for me?

that runner will support at least 460hp. That's the most I've seen out of a Vortec headed motor personally. It was out of 383 inches though.

oh really so 170cc runners are fine for that much power, alright. so do you think that the xe274 would suit me? i will be running 1.6 rr's also, im hoping to run 12's.

Something small that I overlooked when I did my cam swap in the car is to remove the mechanical fuel pump if you have one. Lets just say I forgot and suddenly the old cam wouldn't came out any farther.

BTW, the XE 274 is great in a 350 with good heads. Lots of torque and good pull on top.

yeah alright i plan on purchasing the cam on monday, what do you guys mean by a lazy cam(edelbrock RPM cam), it wouldnt work well with the rest of my setup, to complete the RPM package, or maybe cuz its old, and the xe274 is more common, would the xe284 be too much? its .507 .510 lift, with 1.6rr's they would in the .540's, just looking for the most out of my setup.

also when you say #1 TDC, and put 12 and 6 oclock, #6 will be firing, when its at 12 and 6, can i turn the timing chain to 12 and 12, cuz u said the camshaft spins freely, then with #1 at TDC still, the firing will be at #1 also

thanks

You align the dots to 12 and 6, which is the instance of #1 & #6 TDC that is #6 firing; bolt the cam gear to the cam, with the chain on it, and the gear pressed onto the crank (in other words, assemble it); and then rotate THE WHOLE MOTOR to 12 and 12, using a crank socket or the like - NOT the balancer bolt. That will require exactly one full turn of the crank, and will result in exactly one half turn of the cam. You will then be at #1 and #6 TDC again, except this time at #1 firing. Then drop the distributor in.

thanks alot sofa, that what i figured..

but what do you guys mean by a lazy cam(edelbrock RPM cam), it wouldnt work well with the rest of my setup, to complete the RPM package, cuz u say the springs on the heads are made for this cam, and it suppose to make 420HP. or maybe cuz its old, and the xe274 is more common, would the xe284 be too much? its .507 .510 lift, with 1.6rr's they would in the .540's, just looking for the most out of my setup.

lazy: the ramp rates are weak.

take your advertised duration, and subtract your duration at .050", then compare that to a compxe cam. You can see how much faster the comp cam opens the valves, so it's not 'lazy'. You get more power, and have less lope.
a lazy cam is easier on your valve train, and can take weaker springs, but it's not a good thing for power.
Edelbrock makes a "package deal" just to try and get people to buy all their products, it's not necessarily a good match. Edelbrock cams aren't exactly widely respected. Their intake manifolds are great, and I guess their heads are pretty good too.

i just figured hey have the power packaged for a reason.

is the xe284 too big for my setup? .507 .510 lift, 110 lobe seperation, power 2300-6500 plus my 1.6 rr's would bring them about .540, sounds a little big

so already suggest the xe274 is perfect? and will work good with my setup, but they say i have to replace the springs on my heads.

trickflow twisted wedge 195cc heads? whoa, nice.

I think you're good with the xe274, the 1.6 rockers will make it seem a bit bigger.
The 284 would be a BIG cam, I mean, your heads would support it I think, but it'd be a bit less pleasant to drive. Your call.

What are the specs on your current springs?

i actually sold the trick flow heads, and got set of edelbrock performer rpm's. they handle up to .575 lift i think, so im assuming the xe274 would be nice, and using the 1.6 rr's would bring the lift up to about .520

can anyone debrief me on SUM-K1107, 234/244 duration, .488/.510 lift, 292/302 advertised duration.

the ONLY reason im looking at these is beccuase im starting to get low on funds and wondering if this cam would suit my needs for the motor

355 flat tops, performer RPM heads 60899, rpm air gap, 750cfm carb edelbrock, 1 5/8 headers full exhaust, march pulleys, high flow water pump, would this camshaft put me in the 420HP range, since its close to the edelbrock RPM cam, except a little better, because i listened to the arugment of the advertised duration and this one is a little lower. that package says 420HP

It is absolutely identical to the RPM cam in every way, except price. Smells exactly the same.

The difference in the advertised duration spec is in the measurement technique (specifically, how many .001"s of lobe lift is considered the start and end of the ramps); not anything about the cam itself. It's the same cam.

You don't want it.

that cam is the same as the edelbrock RPM cam, just with a different sticker on the box.

I thought Jegs had compxe cames pretty cheap lately. ie $70?
just checked, the compxe268 is only $70, but the 274 is $100.

If I were you, i'd get the xe268 from jegs. With the 1.6 rockers it'll act a bit bigger, like the 274. Just my HO.

When you've dumped as much money into your engine as you have, it'd be a damn shame to cheap out, and save $30-$40 on the cam, something that effects the motors characteristics so much.

spooky timing...

yeah i guess if i went this far dont skimp out on the camshaft, i need the lifters also so im looking at like 180US which is why i compared it to 70$US, lol, just tryin to cheap my way out i guess, thanks.

im looking at the xe274 and xe,284 just a coin toss i guess

you might wanna take a look at this LUN-60103LK or this LUN-60104LK looks like great grinds to me. I´ve ordered the 504 525 cam

oh right, you're in toronto...

yea, i'm ordering the lunati 60103, which is close to the 268xe (not sure i've already said that in this thread, I say that a lot...), the 60104 is like the 274, might be something to look into.

I priced out the 60103 at mopac (you have those out east?), at $130CA, which is pretty sweet.

What is your source for some of these? got a buddy south of the border you can pick these up from? save the duty perhaps? Maybe f-bird88 has an idea, I think he's in your area.

cheap out on the lifters, they're all the same anyway. See if you can buy the summit brand lifters, those are pretty cheap.

sofa - whats the difference between the edelbrock RPM and the summit brand? i see the lobe separations are 112 and 114, and the summit brand has a little less advertised duration, this is just got personal references.

also, Sonix where do you order your parts from, i know noone being in the states to pick up and drive across the border to meet me.

I use Best buy high performance, or Mopac in town (haven't used mopac yet, soon thought.) Theres probably a better selection in Ontario, I would imagine.

Summit is great too. Summit brand parts are dirt cheap, especially if it's not a super critical part. Usually a rebaged mediocre quality part, ie, cheap chrome valve covers, timing cover, stock style balancer, etc. I just put through a $300 order there.
Check the canadian board, I made a post about mail ordering parts from summit, posted a spreadsheet to calculate a more true cost of the parts, helps add in shipping, etc. eg, If I buy valve covers at $20 from summit, they end up being $38CA when the smoke clears. (in a decent sized order). Better than $75 locally say. PS. Don't touch UPS with a 10' pole.

UPS will screw you right in the *** all the time.

If the 2 cams are on different lobe centers, than that's the only difference. They're the same lobes. Taking Stone-Age lobes and grinding them 2 degrees different doesn't make them any better.

Those lobes have been around for 35 years that I know of. You can get them from just dozens of the generic cam copiers out there. All of those Summit cams are made of that set of lobes. The 204/214 one, the 214/224 one, etc. Some of them are not too bad of cams, for some uses. But none of them is competitive with modern cams, on account of we've learned a thing or 2 as a species about cams and how to make them in the 35 years or more since those were introduced; and cars themselves and speed limits and engines and gasoline and driver expectaitions and everything else has changed too.

"Advertised" duration is measured by counting how many degrees there are between the point where the lobe raises the lifter by some arbitrary amount, to where it returns the lifter to that same point. Nobody uses zero lift, ever. Close but not zero. Everybody picks a number and specs their cams using the number they pick. There is no industry-wide standard, like there is for .050" duration (.050" of lobe lift.... duh) .006" is somewhat common; Comp, and I believe Lunati and Crower, use that. Crane uses .004". Obviously you can take the same cam, and measure the duration between the .004" lift points, and you'll come up with a different number than if you use the .006" lift points. That's THE ONLY DIFFERENCE between the Summit and Edelbrock numbers. THE LOBES THEMSELVES ARE THE SAME; only the measurement technique is changed, which gives different numbers.

Don't cheeep out on your cam. Cams are cheep no matter if you buy the most expensive one you can find. Get the right cam for what you're doing. The difference in cost is so tiny, that one month or less of using the car, can pay the entire cost, in cash, just in gas consumption. In fact, the difference in your gas usage between those 2 cams (XE268 or 274, vs the RPM or Summit cam) DEFINITELY WILL pay you back in cash, in less than one credit card billing cycle. i.e., order a good cam, and by the time you have to pay for it, it will have put the difference between its higher price and the cheeeeep one, back into your pocket as cash. And it will do the same thing the next month; and the next; and the next; forever. Think about it.... you're going to "save" $30 now, in exchange for obligating yourself to spending $30 extra EVERY SINGLE MONTH. How smart is that? That's how poor people keep themselves poor, no matter how much money they make; they make stupid spending decisions like that, that invisibly bleed their cash from them.

Buy a good cam, and forget about the ancient generic ones, because they (a) will lose the race to the better cam, and (b) will cost you more over the long term (and the long term isn't even very long in this case!) than a good cam.