Is the Tpis bigh mouth base overkill on a 305? I am selling my setup to my friend and we are wondering if the big mouth base will hurt performance or will it help any. We have the stock base too but I figured the big mouth would help some with the stock runners and plenum.


James

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If the women don't find you handsome they should at least find you handy

 

on a 305 no intake mods are needed. the tpi system is perfect for the 305. the only recommendations i have are to port your plenum and get an airfoil.
its the 350s that need the bigger intake and runners.

 

James,

I think the answer to your question lies in how fast you want your 305 to go. Granted I am supercharged, BUT I decided to go with all the "big boys" parts on my 305:

SLP 1-3/4" Headers,
TPIS Big Mouth Base,
TPIS Large Tube Runners,
TPIS 52mm Throttle Body,
Corvette Aluminum Heads, & a
Crane 2032 Cam (designed for a 350)
to just mention a few. These are parts typically not found on a 305.

What's interesting is that I have run my car without the supercharger, but with a 90-hp shot and all the aforementioned parts. My best is a 12.58, only 0.01 seconds off my best non-nitrous, supercharged (6 psig) run.

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Willie

Supercharged 1987 305 IROC-Z, Daily-Driver, Emissions-Legal.
12.57 @ 111 mph.
12.04 @ 114 mph (50-hp nitrous).
http://www.ozemail.com/au/jca69/mods/williesz/willie.html

1987 "20th Anniversary Commemorative Edition" Z28 Convertible -- Super Chevy Show Class Winner, 1998.

 

I think Willie has the right question. What year is your car anyway? The cam is probably the first thing you want to change, but changing the intake after you do some other things to increase flow like the cam, porting, stuff like that, the base will definitely help.

 

We are going to put this onto a 92 Camaro RS. The cam would be coming out of my GTA, which has the L98. Basically we have both the stock base and also the Big Mouth, so we want to know if it is going to benefit us even in the slightest way, or can putting on this base hurt. We will use the stock runners and also the stock plenum. Let me know what you guys think.

James

 

If you plan to ultimately swap to a bigger cam and better heads, then by all means, the 305 will benefit from a better breathing intake.

By themself, a complete intake system probably won't do too much (maybe a couple of 1/10ths) but it shouldn't hurt anything. I believe the stock TPI intake is adequate for a stock 305, but it has room for improvement too, even on a stocker.