Patriot

I run 14.0 with my stock 3.23 gears . What would I run with 3.42 gears ? Thankx ... 350 TPI , auto

Patriot

Anyone ????

unvc92camarors

you'd notice a slight difference with the gears, and my guess is maybe anywhere from .1 to .4 seconds faster

Zepher

If you are going to swap gears, go 3.73.
There is so little difference from 3.23 to 3.42 that it's not worth the money.
My friend has 3.73 gears in his 86 Z28 and they feel really good and his car still gets decent gas milage.

Aron213

Zepher, by running 3.73's with a 700r4 will net you a trap RPM in 3rd gear of about 5400 which is about 600RPM past the power band of a TPI unit. With a carb or other form of EFI those 3.73s would be perfect but not with TPI.

I wouldnt go any higher with a TPI car than 3.42/3.45. And like it was said earlier you will see between a .1 and a .4 decrease in time.

Patriot

Speedo difference ? What I'm asking is if I'm going 50mph with 3.23''s I'll be going 55 with 3.42's @ the same rpm ? Ya'll know what I'm asking . I know the higher gears makes you go a little faster than what the speedo says unless I burn another chip to match up .

Zepher

Depends on how fast your car is.
If I put 3.73 gears in my car, I'd hit 92mph at 4500rpm in 3rd.
At 5Krpm I'd be at 102mph, which is about what a modded 350TPI may be at at the end of the 1/4.

4800rpm nets you 98mph in 3rd.

Patriot

I'm asking how much of a difference in the speedo . 50 mph is 50 mph with the 3.23 gears that came with the car . If I install 3.42's and the speedo says 50 mph will I really be going 55 mph ?

unvc92camarors

for the speedo, i think you're right
you'd only be about 5mph or so off if you ran 3.42's (i cant remember whether the speedo would read 5mph FASTER or slower)
jus a swap of speedo gears should take care of that (about 15 bucks together)
and i think aron213 said it right- dont run higher than that probably because you get yourself out of the tpi powerband
if you do go higher than that you'll have to do stuff to the engine to make it be able to run higher up in the rpms to get the most effectiveness out of the rear gearing