Hey guys, I've got a 305 w/ nice cam, headers, SLP runners w/ upgraded exhaust, custom chip, pulleys, K&N filter, AFPR, etc. The car runs extremely well, but I am wondering if I will see a "dramatic" (or noticeable) improvement in times by upgrading to a 52 mm throttle body. Also, what is the "average" gain by throwing on the TB alone, as well as with a larger TPI base, or ported stock base? oh, one last question: Would I gain anything by upgrading injectors at all, or would that be overkill?FYI: I just bought the car; the previous owner ran it in the high 13s, and she pulls up to 6K.

Thanks for any help, am new to TPI...

MILT



[This message has been edited by MILT (edited August 16, 2001).]

 

Milt, I'd say with a basically stock 305 you would do better pulling the stock intake, plenum and runners and porting them out. The air flow you are dealing with would not be helped by a larger TB. Save your money, pull the intake stuff and port and polish them. I ran 14.21 with my stock 92 Z28 convt, 305TPI, 5spd 3:08 posi rear/stock Eagle GA tires. I ported the everything and the 305 breathes much better.
edit: I definately don't think anything would be gained by increasing injector size on a 305.
Bottom line, I don't think you'd see much improvement with just a 52mm tb.


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Rob P
89RSconvtZZ4TPI Edelbrock Intake
SLP Dual Cold Air Intake 1 5/8" Headers Semi-Siamesed Runners, IROC
suspension, alum shaft. Numerous mods.
92Z28convt5spd (stock)
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

[This message has been edited by Rob P (edited August 16, 2001).]

 

I agree with Rob all the way on this one. I have heard of a lot of people pulling some incredible numbers with the 48mm (stock) TB on 350's so I would say save your money that you would spend on the TB and put it towards something you really need. Port the entire TPI system. Lower intake, plenum, and runners even the SLP. The larger injector size would be over kill unless you ran some power adder like NOS or supercharger. Since you have an AFPR you can adj the fuel to flow what you will need. you could do some suspension upgrades to plant that power to the ground like LCA's, Adj Panhard Rod, if you dont have a wonderbar throw one of those in there, new shocks, struts, Strut tower brace, new gears just some thoughts for you to throw around.

 

Thanks for the input. I already have rear susp package, SFCs, STB & wonderbar, so I figure that I have the suspension portion taken care of...

I've never tried porting/polishing b/f, is it a fairly straight-forward process, or is it better to have it done professionally?