I have a 91 firebird LO3 5 speed the car pretty much stock except for flows, edelbrock ari cleaner and a Jet chip.

I know this question has been asked before about the automatic LO3 but My questions is does anyone know what a 1/4 mile time would be for a stock LO3 5 speed? and how much do the mods that i mentioned above help the cars et time if any? thanks in advance.

 

Really depends on how well you can shift and launch with a standard trans. Those mods won't do much, I haven't heard anything good about a jet chip... actually I think I've heard people say to ditch it but who knows. I'd bet you'd run about the same as any of the other stock L03 times.

 

I've got a Camaro convertible 5speed, so it's a bit heavier than yours would be. I had an open element and I think 3.42 gears at the time and ran a 15.7 at maybe 87 or 88 IIRC, was also on a super hot day, with good shifts. I'd think in perfect conditions you could hit low to mid 15's.

 

My last bird was an 89 LO3 auto and it was much slower than my 91 LO3 5 speed in stock form, as far as the chip goes i can definitly feel an improvment.

 

Low 16's to high 15's is the norm. A good running car with good driving should yield better results. 90RS305 can a 15.3 bone stock with his LO3 car.

 

I ran a 15.5 last fall (temp was pretty cool) with a mostly stock L03 w/ T5 manual trans. At the time it had open element, headers and cat back with base timing advanced 3*. I could probably have run a bit faster with better shifting. Since then I've swapped out the 3.08 open rear end with a 3.73 posi and began my own chip burning to optimize the tune. Based on A-B comparison with gtech I've improved about .5 sec with gears and tune so far, so I should break into the 14's when the track opens this spring.

 

Excellent! You will have to post your results. It is great to see deticated TBI tuners out there. It just goes to show you that once you undersand a system you can make it pretty darn quick without much money.

 

Thats great im planning on intsalling some header and cat aswell this spring.