I have just bought a 88 Iroc-Z 305 TPI 5-speed. Just finished all the body work and paint, time to do the engine. I don't want to change to a 350 so don't go there. I would just like to get a little more HP from my 305. The spec's read 220 HP I would like to get 300.

So here are my questions, and please let's not get into a 350 vs 305 debate.

1) Who has the best headers? Also are shorty hearders really any good?
2) Who has the best runner and base combination?
3) Would it be wise to go to Edelbrock aluminium heads?
4) Lastly, what would be a good cam that's has just a little lumpy idle?

I have already spent $ 4,500 on the paint job (white pearl with blue undertones, looks great) I have $ 4,000 Cdn for the motor.

Thanks for your help!!

 

Here is my opinion. Use an Accel base with a set of large tube runners. Don't wast the money on a throttle body. Your stock one will be just fine for the power level you want. Get an air foil for it. You do not want to use long tube headers for your motor. Get a set of Jet Hot headers from "Mac" if you can. Get your favorite cat back exhaust. They are all about the same in performance. I am not a fan of anything from Edelbrock. I was not aware they made heads for the 305. I had great success with L98 aluminum heads on 305's. As for a cam, the TPIS ZZ9 cam or the ZZ4 cam from GM would be very good choices. They don't have much "lump" but they make very good power in the "little" motor.


Good luck
Jeff

 

Why not go to long tube headers??? and should I port the plenum, runners and base ??

 

LT headers will kill your clearance. OH YEA deff. port your plenum. That can be done with a dremmel and some bits. runners i belive you can use a dremmel too, but the base is where you need a die grinder. I wouldnt put on new runners and base, cause the tpi flows enuff for the 305 now, and if you need more, porting the base and plenum should hold you off till major mods come. if you go with bigger runners and base that would just kill the power. But if you put in a cam, heads, valvetrain, exhaust.... then i can see an additon to a runner/base swap. Sounds like a great car you got there. any pics? if you want some (crappy) pics of my ported plenum, ill send them to ya. oh yea.. about heads. There is very little in the head department for 305's. you have basicly a choice of the SR Torquer 305's, or a set of ported L98 alum vette heads. no one else makes aftermarket heads. for 305's.

 

Ed a.,

Welcome Aboard!

The factory TPI runners and base are pretty well sized for the 305. It never hurts to clean up the casetings and match the openings to correct for core shift. The area behind the throttle body can be quite restrictive, so a little machining there can pay off.

As for headers, the Edelbrock TES headers or any similar design seems to be a well engineered solution for the 305s.

I'll agree with JeffBlue that a larger TB and gutted MAF sensor are a completely unnecessary step for a 305.

World Products S/R torquer 305s are a decent off-the-shelf setup, but a set of '416 castings with valve and port work can perform very well.

If you're keeping the TPI, a Comp 262HR-12 or 264HR-12 is a good choice that will still be streetable. Of course, appropriate springs and rockers will make the most of that lobe profiles. Even a take-out LT1 cam can make some nice improvements. Since you have a MAF system, ECM reprogramming won't be necessary to make the engine run well, but as always (even with a stock engine) a little PROM tuning can squeeze more out of the setup.