garlicbreath

I am building a SBC 350 with sportsman II 220 cfm heads, 1.44 dual springs, rpm intake, holley 670cfm carb. Block, crank, rods and cam from a 91 9C1 cop car. I might run 1.6 roller rockers but not sure. I am looking for roller cam recomendations. Must fit a stock roller block. It is going in a 1971 blazer that gets driven maybe 3000 miles a year. I use it for wheeling, 4.56 gears, 37 inch tires etc. I am thinking the factory LT4 or ZZ4 cam is a bit small. Any ideas? What problems have you guys run into with large cams?

TraviZ

iTrader: (2)

see the one in my sig? buy that one, in fact i have one still brand new in box. that lift number is with 1.6 rockers, its .510 and .520 without. ill let it go for 200 shipped.

Sonix

iTrader: (1)

you're asking on a sports car forum, for a very specific recommendation for a cam for your truck, which has completely different needs then most of the cars here...

You probably don't want a large amount of duration for a vehicle that wants to be in lower RPM most of the time.

Why not ask on fullsizechevy.com or something?

brutalform

I understand that you are a new member, but, there is nothing in your post that refers to a third gen. At least if you were refering to a TPI, someone would probably help. Caprices, and Blazers, are off topic here. My advice is to pick a reputable cam company, and ask them.

SLEEPER 86

what transmission and stall do you have now? that will make a difference when you decide on your cam.

what does it weigh?

with 220 cc heads and a 4.56 gear you might as well look at a 7000 rpm shift point.

what pistons? make sure you have adequate valve to piston clearance!

those heads are really gonna want to breathe!
i'd reccomend a cam in the .560 to.580 range,duration should be determined after the final drive ratio is known.
my guess would be in the 292-300 advertised and 236-242 intake duration at .050. IF you have a standard trans,or the stall (3500++)for it.

if you pick the right lift cam in the first place,you don't need to use higher ratio rocker arms.that saves on valve train wear.anything you can do to lighten the valvetrain is a bonus,but there is nothing wrong with good stamped steel rocker arms.the comp roller tip ones are imho the best bang for the buck,but with the cam you need you might want to use the pro mags.they will fit a 1.44 spring,but i hear they have trouble with a 1.550.
i think you can find a cam that will give you the rpm's you'll need with a 1.44 spring though.

you didn't mention the intake did you?i'd think an edelbrock vic junior,it would match the cam nicely.

if you want a total torque monster, keep the lift, and drop the duration to 228 @ .050 or so

post trans type and converter and i'll throw you a few reccomendations.

Eric B

garlicbreath

I am, I have asked on 5 or 6 different forums, but the problem is most guys that wheel their trucks use older trucks, pre roller cam. Didn't think it would hurt, and does it really matter that much? When I am crawling on a trail the motor is anywhere between 1500 and 6000 rpm anyways. If I wanted a slow torquer I would have put in a diesel.
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Way to welcome a new member, and from a moderator no less.


Does it matter that much what the engine is going in that you don't welcome the post here? Motors are motors, you think the ones in a baja 1000 truck are THAT much different from a nascar engine?

garlicbreath

Duration is one thing I haven't looked into yet. What effect does it have on power output?

brutalform

Garlicbreath, you have a PM!

Sonix

iTrader: (1)

the handful of times i've been in an offroad situation in a 4x4 truck, it seemed to me to be mostly low end. You'd have a hell of a time using a high duration cam, as it'd be all top end, and no low end torque (which is what you'll need in that situation).
since *most* of the members here are interested in 3rd gens, and motors pertaining to them, I think you'd get better advice on a truck forum, and i'm pretty sure they know roller cams too.
try comps xe 4x4 roller cams, that should be what you want.

garlicbreath

OK, I get it. I mentioned truck. BUT, this motor is EXACTLY like most of you would build one for your third gen. Oh, and by the way I have owned 2, and I still yearn for another GTA. I also had a 66 chevelle, I just chose to have my fun in a place where cops don't prowl. I was really hoping to get some engine specific help here, and was pointed to this site by 3 off road sites. I still have a few questions, like which timing gear set do you guys recommend, which intake gaskets would you use with my heads, etc. Am I because I mentioned a truck now?

19doug90

good website Fullsize Chevy.com

First of all just fyi the whole point of this board is its 100% third gen specific. If it doesnt have to do with a third gen motor, or a third gen vehicle it doesnt get talked about. People get touchy about it because as soon as we let one or two posts non third gen specific get in, then a whole slew of them get in and the board is ruined. It means a lot to us and we try to protect it.

Second of all the motor you are making is NOTHING like what i would put in my third gen. I want peak power at around 5500 rpms in the motor im building. Youre going to be more concerned about peak torque at like 2000 rpms.

As far as the combo you are using, well keep in mind im just a 19 year old kid and dont know what im talking about, but this is what i think.

A head with 220 cfm on the intake side would be way too big wouldnt it? you need that kind of flow if youre trying to make 500 horsepower.

Understand that when you have high volume, you lose velocity, and the other way around. You want velocity for lots of low end tq, so flow isnt quite as important to you.

I would probably buy some world products s/r heads 170cc intake, a cam with as low duration and as much lift as possible, and either a stock TPI intake, or a holley stealth ram. Go with 1.6 rockers for sure because youre going to want to have a lot of lift.

Make lots of tq and not a ton of hp, which is fine caus eyou dont need horsepower

i could be wrong tho

EDIT: oh and seriously the best help you can get, go to a shop man. Find a good shop near you that deals with a lot of trucks. OR even find a performance motor shop, im sure theyll know what'll work in a truck.

Sonix

iTrader: (1)

we can give you plenty of advice on how to hotrod that motor, (best if you didn't mention truck in the first place ) but it would SUCK if you used it for offroading, I mean stalling it 'cuz of a high load at low RPM going up a steep incline....

that young'un there has good points about the velocity, if you want a good truck motor, that's what you want. if you want a hot high RPM motor, you're on the right track (but again I think you'll regret it if you seriously use it for offroading).


using a timing gear, not a chain? That's been disputed on these boards a fair bit, and basically the consensus is that a gear isn't a great idea. Get a good double roller (comp magnum is good), or a TRUE ROLLER if you can afford it. (not as pricey as a gear set). Any basic fel pro intake manifold gasket set should work fine, not a high risk thing there.

brutalform

I cant believe how you continue to try to get around the rules, and keep dragging on about your engine for your Blazer. Just because you "have owned" third gens, does not mean you can continue to go against the grain. Your questions are NOT third gen specific, and, after the fact it has been brought up by a few members, and myself, you just go on, and on. This thread deserves to be locked! At the very top of this board is a post by our administrator, I suggest you read it!

garlicbreath

Of for gods sake, can a mod please remove this whole post. I will go elswhere and never ever recommend this site to anyone I know. Even if they are a thirdgen ahole. You mods might as well wear white sheets and hoods.

Sonix

iTrader: (1)

Geez you are grumpy. You've got plenty of suggestions here, and you're still sore? Take a walk bud.

garlicbreath

I am not sore, it's just posts like this that make me feel VERY unwelcome.

19doug90

thats cause your post was unwelcome, man are you slow

five7kid

iTrader: (14)

Okay, enough is enough.

This is a 3rd gen f-body site. Always has been, always will be. We'll make allowance if the topic can be applied to 3rd gens, but since this topic is specific for an off-road 4x4, it simply isn't going to be built like many people would their 3rd gen. I have a co-worker who is into the rock climbing stuff, we talk from time to time about our projects, but cam selection is certainly not a place where common ground exists.

So, let's say, "Goodnight, Gracie."