cort351w

I want to get into burning my proms in a few months, but I don't have time right now (BTW, I know absolutely nothing about the subject right now).

I have a 91 formula 305 tpi, 5-speed. The motor is completely stock for now. The whole car has 20,000 miles. I am putting on 1 3/4" SLP headers (probably too big, but I got a great deal, and many people with 1 3/4" on 305 say it's great) and a custom (self-fabricated ) 2 1/2" dual exhaust with cats. Should be a good system so just think of a nice conventional exhaust if this factors into my questions. Also, I am porting out my tpi (not sure to what degree and how much, if any, siamesing I will do). Oh, also K&N filter with custom-bent exhaust pipe from filter to TB and (hopefully) cold-air induction.

These are my questions: I know these are not very radical changes, but what will hapen when I start my car back up as far as fuel, spark, performance, gas mileage?

Will I (and how badly will I) need to change my prom? What kind of benefits and how large or benefits can I expect a custom prom to give me with this setup?

If performance and/or mileage will suffer, would it be worth it to get a professionally done custom prom until I can do them myself? How much does this typically cost?

Thanks in advance

RCR

What you are doing will free up the breathing of the engine, but it is nothing radical. A new chip might help overall performance, but the stock chip should be fine for now. You won't see big gains until you do the heads and cam.

Grumpy

For the price of most of the aftermarket ones you can be ding your own.
There are lots of options and things to timker with. Learning with a stock motor is an excellent first step.Performance, and MPG are hugely efffected by your driving style no one can quarantee you you will get better are either. But you can talylor the chip for the way you drive.

Start reading there is a vast amount of info around

cort351w

ok, I have been reading this board for only a few days, but I'm starting. A little knowledge is dangerous, huh. I read some of the stuff on here about mods that increase airflow leading to a lean condition. I was really wondering if my performance and mileage would be hurt by the aforementioned mods with no prom change--that's why I was wondering if I should get a chip made for me until I can get into making my own.

thanks