I ran a 14.87 @ 90.95 mph on my original 305 (peanut cam) with a ported plenum, Hooker 2055 headers, cat-back exhaust, 2200 stall converter, 3.42 gears/posi, and burning my own chip. I didn't have an air pump or cat, but did have the A/C hooked up and running (not at the track of course).

 

i ran 13.80 with my 305 (headers,intake,spark pluhs cables,exhaust,-
and a brand new 3.45 gears.)

 

15.1 @93 mph , with 227'000 km's on a hot day about 1000 ft above sea level. With MAJOR blow by. ( kicked off track for spewing oil out the dipstick) .



Forgot to add it was a 5 speed with 3.08 LSD

 

Wow. To me that time seems really good with just those mods. I guess i should get a set of 3.45's?

Heres my best time with the IROC.
86 Iroc-Z LB9 Auto.
Stock, except for K&N's, a flowmaster muffler, and 3in cutout

1/8th Mile
9.87 @ 70.09 MPH w/2.16 60'

 

That's pretty fast. No porting, heads, or cam? What were you getting for 60' times? All stock suspension/drag radials? That 5pd and 3.45 gears must make the difference. -Nick.

 

I'm shooting for 12's.

 

So, 3.73's would make that much of a difference? What were you stock gears? -Nick.

 

What was the headers and exhaust you had on the 305? When I get a catback, my mods will be very similar, except 3.42s instead of 3.45s.

 

Hey Lucid. Next year I am likely going to install a Magnaflow cat, new AC Delco CR45TS plugs, learn how to do some tuning, and fix my intake manifold leak. Then I think I should run a 14.8. Once I've done that, I'm probably done modding my 91 GTA.

I bought a 92 GTA 350 TPI from California in September that I am in the process of fixing up and I am going to do a few mods to it too. Right now it is bone stock, it even has a paper air filter.

 

Andy
That sounds good, get the biggest cat you can fit on there (make sure its a high flow one), i have 3" exhaust starting with/from the Cat going to the big Borla muffler. The 305 engine is also very sensitive to timing. With the timing at around 0 deg base, i was running 16.8 in the quarter, and bumping it up to 10 deg base at the track, i dropped it down to 16.2.

Good luck with the GTA

 

12.31@108mph n/a and still daily driven...but i'm carbed...

 

Looking to get it going a little better after I change the cam over the winter!

 

my '87 LB9 iroc runs 15.5 @88.2. i have managed a 2.16 '60 foot time, hooks up good but doesnt pull hard. all i have done to it is a TPIS airfoil and a GMS adjustable MAF sensor.

 

That car is just plain nasty... man i know some people with built 383's that cant even pull those numbers!!

 

it's getting there...people don't believe it's a 305 anymore though...it's kinda annoying, in a cool way!