ok i have a 87 LB9 iroc with 75xxx miles. ive got shorty headers full 3" flowmaster exaust w/o cat k&n filters with a full tune up and the best time ive gotten out of the car is a 15.5 @ 87mph. id like to put it in the mid to low 14s or would it be just polishing a turd with a 305?

 

Easy cheap way gears !!! Shave almost a full second if you go to some 3:73's

 

3.42's and 2600-2800 stall is a start with drag radials (NOT nittos) or ET streets DOT radial bias ply slicks. Then start doing some more bolt ons. Converter/gears should get you high 14's as it sits. To get low 14's you need traps in the low 90's mph to mid 90's mph. Still a good ways off from that. Do the basic mods...pulleys, gutted air box,

Advance timing from 6 deg base to 8 or 10 and run 93 oct. Try that to see if it picks up.

 

cool thanks! what a chip do any good? what about getting the plenum base and runners port polished and saimiesed?

 

IF you wanted to try ported base and plenum along with siamesed aftermarket runners, thats a good step in the right direction.

Chip tune with the above mods will be beneficial. GM tunes seem to be on the rich side from the factory. I know my bolt on car was in the low mid 12's to 1 air fuel. Lean it out some and get abit more aggressive with the timing curve and you can see some hp out of it for sure.

 

I agree that your 2.73 gears are hurting your times, but the thing that's really holding you back is the cam. Get rid of the peanut cam and you'll be well into 14's.

 

Man I'll tell you what, with your connector for the timing attached, when the cars warmed up in closed loop, adjust your base timing, at idle, to 16-17* and see how it runs, rev it up and if you don't hear any pinging or knocking, then go run it at the track, and feel how it drives! It will show you what you got! A lot of people don't put any timing in there motors, and timing is everything for power, so try this, and you'll be surprised. I ran 16-17 in my 350 iroc and ran 13.81 at 99 with a slipping trans and 156K on the clock

 

Dang, i will deffinetly have to do that come spring, it seems like thats alot more than what other people are runnin for bumping up their timing

 

with my iroc after I put my edelbrock headers and a bullet muffler and dump on. I had manual steering, so no power steering pump, and only the alternator and water pump and smog pump. I started with 8* base timing, at a 15.1 at 89. Then I adjusted my fuel pressure to 50.5psi, removed the smog pump belt, adjust my tps to .45 since I raised the fuel pressure, and adjust my timing to 16.5* and put my drag radials at 24# and I was able to get it to 13.81 at 99 mph with over 140K plus miles, with a slipping trans! Fuel pressure and timing has a lot to do with how much power you can make, and keep in mind, the TPI intake was made for a 305 so you can shift at 5500 r's

Check this page out this is my iroc, its gone now:

http://www.cardomain.com/ride/471099...irebird/page-8

 

was urs also a 305? and thanks i think ive got alot of ideas on what i think im going to do now is just the time and money. id really to put it into the low 14s on motor and possibly a 100 shot at it to put it into the 13s but the spray will be towards the end but ill have to see when the time comes, people just dont have alot of respect for 305s or really third gens at all in my area. id like to be able to be one of those guys and say hey you just got beat by a 305 lol

 

No mine was a 350 L98 TPI motor, look at my page for more details