BADMAN

iTrader: (13)

Looking at a Crane part# 114132 camshaft for my stone stock 305/TPI auto trans 3.42 Iroc. Specs are 210/216 duration at .050 lift,440/454 lift,114 degrees lobe seperation,flat hyd. Any pros or con suggestions welcome. Looking for a little better performance without my stock computer going crazy!

Kevin91Z

iTrader: (1)

That is right on the edge of it working with the stock programming in the computer. You might want to look for someone local to you who can do chip programming just in case.

five7kid

iTrader: (14)

I don't know, it shouldn't bother a MAF system.

BADMAN

iTrader: (13)

Could you be more specific? What potential problems could I have?

89RsPower!

I know this has little to do with cam selection but you stated it's "stone stock", so am I correct in assuming factory exhaust as well? If that's the case you'd probably be better off spending your money on an exhaust system, manifolds back if more power is your goal. It makes little sence to start doing engine work when the poor thing can't breathe. Headers back is the best hp per $$ u can do to these cars.

BADMAN

iTrader: (13)

Forgot to mention that I will be doing a standard valve job and installing Hooker 2055 headers with the cam change.

1991 RS 305

BADMAN, heres a thought: I assme you want this for your 85 IROC. The 85 cam was decent, but I'm looking for a bit more for my 85 TPI also.

I've been looking at the Comp XE256H-12 for my 305 TPI. This is a flat hyd 212/218, .449/.456, 112*LSA. According to my research, this is TPI friendly, I think its about the most duration or tightest LSA you can go before needing a chip burned, and 'could' be boarderline at that. If chip burning was needed, it should be mostly for increased curb idle. The 85 computers were slower than later TPI's, but the program had good fuel and spark tables.

When you do your valve job, you might consider porting the heads and getting a 3 angle valve job with back-cut valves. This will improve air flow, especially at lower lift, even if you didnt change cams. If you do change the cam, so much the better.

Kevin91Z

iTrader: (1)

It could run rich at idle, have a surging idle, and hesitate or bog on acceleration, for example.

five7kid

iTrader: (14)

I used the next step up Crane compucam in my computer carb 305. It was fine.

I won't try to put myself up as the guru of computer controls, but from what I understand, the biggest issue of too much overlap is the O2 sensor getting fooled by raw or partially burnt fuel at idle/low RPMs. With 114 LSA, that isn't going to be a problem, and Crane specifically designed this cam to be compatible with feedback computer control systems.

The MAF system isn't as susceptible to engine changes as the speed density systems are. I just don't see this cam causing problems.

While I realize that CC carb and TPI aren't apples to apples, my 305 did pass the Colorado dyno emissions test with a "fast pass" - meaning the readings were so low that the system didn't require the car to go through the complete testing cycle. And that was with Crane's even more aggressive cam, with a system that isn't known for being as clean as TPI - but still can be susceptible to "O2 head fake".

smallblock383

Funny...I ran a Comp Cams Extreme Energy roller cam (.212/.218 @.050 .488/.495 lift with a 110 lobe seperation), and I had NO problems with the car running correctly with a stock chip. (1988 IROC Z MAF equipped) I just adjusted my timing, set my throttle position sensor...and off I went. I also matched new springs and a double roller timing chain. I also put on an adjustable fuel pressure regulator. Having a 110 lobe seperation gave me that shaking and choppy idle that I wanted and it sounded great with the headers and 3'' custom exhaust. I called Comp Cams and that cam is speced to work with a stock computer and 3.42 rear gears they also suggested a higher convertor....I did all my homework when I did this swap...all of these people get so squeamish when you say 305TPI...(F.Y.I. it did run slightly rich at idle but never hesitated, and kicked lots of *** out of a stop light. Everyone thought it was a built 355...but it was the lowely 305.

Damon

A roller would be nice, but that would be pricey putting it into an old 1985 flat tappet block. I think you picked a good cam that's "one up" from stock. Slightly more duration, slightly more lift, slightly tighter LSA. Should run pretty good in a MAF-equipped TPI without tuning.

Agreed with above, I've gone a scosh bigger on the cam in a stock TPI and had good results, but there's little reason to "go with the biggest one possible" with a near-stock 305 TPI. It might still run reasonably well, but it probably won't get to the end of the track any faster.

Guest

The first cam posted will work fine with the stock programming, at least as well as the stock programming works with the stock cam. I also ran a 212/212 .444/.444 comp cam and it was fine as well, I figured the 212/218 posted above would have been a better choice given that the factory heads prefer a split pattern.
Tuning as always can help but IMO on your application isnt totally necessary with those durations.