TraviZ

iTrader: (2)

230 int./244 exh. @ .050
Intake Valve Lift with Factory Rocker Arm Ratio: 0.510
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.540

its the comp 08-306-8 grind

112lsa

too much? too little? im new with 383's i hear they need a lil bigger cam to get the same powerband as a 350. whats your opinions? this is for a daily driver and strip car.

11 Flat

Do you know what the heads Flow? And what type are they?

e-man

I think the general rule is a cam will peak about 500RPM lower in a 383ci vs. a 350ci

TraviZ

iTrader: (2)

11 flat, the heads are about 258/190 @ .500 and 257/200 @ .600


e-man, i would need about a 230ish duration cam to get the rpm range up to the 2500-6000 range u think?

izcain

One thing that you need to be careful is when you run anything with over 480 or so lift you need to be careful and either run a smaller base circle cam or you need to clearance the rods since they will come into contact with the cam.

TraviZ

iTrader: (2)

never quite understood that, is it the lobes that would contact the rods?

and if so, would i be able to buy the cam, stuff it in the engine, bolt maybe just one rod to the crank and bolt up the timing chain, and get rotate the assembly to check for clearance?

izcain

not all the rods will contact the cam lobes only certain ones and I found that it is only with cams with upwards over 480-490 lift and anything above that. Machining of the sides of the rods for clearancing is a simple and effective thing and nce you do this you can run any size cam you choose.

TraviZ

iTrader: (2)

well i should check clearance before getting the assembly balanced correct? so that mean bolting it all togther snug and spinning the **** eh?

izcain

Most machine shops I have been to that build several 383 will know how much and where to machine the rods for clearancing if you tell them you would like that done. Im sure they can clearance them all and then balance the entire assembly before you have to install everything.

TraviZ

iTrader: (2)

ok ill talk to them first.

11 Flat

I would use something with a little less exhaust duration.

Apeiron

You'll need to check more than just one rod, some cylinders are more prone to interference than others. Preferrably, you'd test-fit the entire assembly checking for clearance everywhere before having it balanced.

I put a fairly similar cam (XR282) into a 383 recently. There were solid hits on several cylinders. Grinding on the rod bolts wouldnt' have been enough to make it work.

Sonix

iTrader: (1)

You'd need to get the rotating assembly rebalanced after that anyway right? I mean, if grinding the rod bolts would have worked, you'd need to rebalance it anyway right? may as well let the machine shop do it all eh?

Apeiron

Well, if you take a very small amount of material off the rod bolts it wouldn't be such a big deal, but if it's anything substantial it should be rebalanced.

There's really no reason the machine shop has to do the clearancing, they'd be doing it the same way you would. To clearance things properly can involve a lot of trial-fitting, which can get time consuming. I'd rather do it myself than pay someone for it. As long as you eliminate clearance problems before it's balanced you avoid nasty surprises.

Speedocrash

I jsut assembled a 383 stroker myself. I used the Scat stroker rods. I had a stock set of 5.7 rods to use w/ ARP bolts. I sold them and used the $$ from that buy the Scat rods. I'm not sure what it would have cost to get the stockers reworked but i think i came out around the same $$. They use a bolt that goes into the body of the rod instead of a bolt and a nut. If you pick up "how to build max performance SBC on a budget" by David Vizard they go into detail of how much must be removed from the shoulder of the rod bolt.

Apeiron

Those are "cap screws" on your new rods, instead of "rod bolts". Cap screw rods can offer a lot more clearance than a stock rod.

In my case, I was using stock rods with ARP bolts that were already clearanced, and there still was no way they were going to work. I used a set of Eagle H beam cap screw rods and have lots of room now. The downside was that the H beams needed more clearance work at the oil pan rails and cylinder bottoms.

A small base-circle cam may avoid all these problems, or it may not. The only way to know for sure is to try it.

Speedocrash

Ape; I knew what they were called, I paid for them. I was just tryig to give a better description of how they looked.

You are 100% correct "Cap Screw" is the correct term. How much lift does that cam have? When i set mine up i was 1 tooth off and ran it 345 degrees around before it hit anything. I was LIVID untill i realized that i was an idoit. Thought i paid extra for the special rods and they still wouldnt clear. My cam only has .455" & I dont suspect i'll run into any problems once i uprgade to a Voodoo series with .489" lift. Time will tell.

-Steve

Apeiron

The lift of the cam doesn't mean all that much when it comes to rod clearance. The lobes are at about the same height regardless of the lift. The duration and ramp profile have more of an effect on clearance.

Streetiron85

Preassembly is the time consuming and costly part of clearancing the rods. Supposedly, some shops have enough experience with strokers to do it without the preassembly. But I personally don't trust the engine builders in my town to do something like that, so I always feel better about pre assembling an engine myself.
I did it by getting a used rod bearing that is the right size, and one cyl at a time, checked for clearance against the cam and the block as well.
First do the crank all by itself and see that it spins freely. Then with the cam in place take the pistons and rod assys, and try them out in their respective holes. Number the pistons so they'll go back where they came from.
The used rod bearing is so that you don't chew up a new one by moving it 8 times.
Bushed rods are a big help too, that way you can take them apart for balancing after clearancing.
I like preassembly, cause it's a good way to be sure the job is done right.
Cleaning the engine yourself with the cam bearings out is a good idea too. Especially if you're getting someone elses block, and you don't know where it's been. Most shops don't brush out the oil passages, they just boil it out and let it go at that.
I've discovered that by leaving things to chance, the likelyhood of something going wrong is greatly increased.
With a hi-$$ motor that has forged parts, I'd leave as little to chance as possible.

Apeiron

I keep a few extra sets of bearings around for that kind of thing.

TraviZ

iTrader: (2)

i have these eagle forged rods with the arp bolts, that have really small heads on them that have been ground from the factory for clearancing it looks like. this should help yes?

Apeiron

It may help, but it may still not be enough. The only way to know for sure is to mock it up.

Tibo

iTrader: (15)

I would get a cam with more intake. I would get a singel pattern cam for those heads and your good exhaust. As long as you don't get into nitrous The single pattern will usually beat the dual pattern.

TraviZ

iTrader: (2)

do u have any single pattern recomendations?

my valves are 2.08/1.6 so the extra lift on the exhaust may be benificiary because of the extra then standard sized valve.

or what if i just put 1.6's on my intake side that would be .544/540 lift.

Free Bird

iTrader: (1)

That's an old camshaft design. I'm using it in my 355. So yes, get a bigger one.

TraviZ

iTrader: (2)

u guys say a single pattern, so show me one that would work for me.

Free Bird

iTrader: (1)

What gear, transmission, heads and intake are you running?

TraviZ

iTrader: (2)

3.42
700r4
canfield 64cc 190cc heads-aluminum
stealthram

Free Bird

iTrader: (1)

According to chevy hi-performance mag, they flow tested the heads and they maxed out just over .500 lift. Do you have other flow numbers for them? If not then I wouldn't get a cam w/ more than 525 lift. W/ no power adder a single pattern cam will work fine, although you can't go to crazy on teh dur. b/c of the 3.42 rear. I'd pic somthing between the 236-244 range. obviously 236 being the lower performing but matching better w/ the heads and gear. The HSR likes more dur. and flow numbers close to 270cfm or more. Although this would req. more rear gear and a higher stall. Hell, the 236 would like a bigger stall as well. The choice is up to you. How far do you want to take the car?

stevo the torpe

i had to clear 2 rods off and i have a 383 234/234 dur and 488/488 lift maybe a 16th of an inch not much at all only thing is throw a hot cam and crank and it will hit

LilJayV10

iTrader: (5)

I put a 288XR cam in my 406 w/ 5.7 rods. I used stock rods w/ ARP bolts. I had to grind on every rod. If I had used cap screw rods I don't think 'i would have had a problem.

TraviZ

iTrader: (2)

Bringing back the dead eh?

cap screws are cool for cams, my new (second) 383 I'm building, I used a regular base circle cam, 236/248 duration. 560ish lift. and the rods cleared it just fine, eagle H beams to be precise. unfortunately the cap screws now contact the bottom of my cylinders, so more grinding is necessary.