I just got my Hedman lt's installed and plan to have a 2.5 inch Y that runs into a 3 inch single (no cat) with a bullet muffler to finish up the exhaust. I run a constant 9.5 on my 8th mile with my 84 l69 t-5 on the original exhaust, cat, and street tires. Only mods are a Holley 670 and a Performer rpm intake. Any idea if these Hedman Lt's will net me a gain of .2 seconds or greater with the new exhaust setup.

 

I think you will definitely get some gain out of it, hard to quantify due to the spread of only .2 seconds. Because of reaction time, etc., many variables. Why do you need to know, did you make a bet?

 

No bets, just trying to catch up to my buddies cars. They have a ls1 formula and lt1 93 z28. Trying to get into the 8's with them with my 305 without having to change to a 350. I like to be different. I figure if I can get low 9's with this....Then my cam when I install it should push me into the 8's.

 

What is your average mph when you run in the 1/8th? Or should i say best? I believe the exhaust/headers will help. It would be a good time to play with igniton timing and carb tune for max results!

 

I can't remember my mph, I want to say 78. Can't quite remember tho. I have it advanced 12 degrees

 

i would try for a 3" y, no reason to bottleneck down if you don't have to.

we installed hooker 2055's and a 3" aerochamber catback on my buddies 85 LG4, and it was a whole new animal. since you have the bigger exhaust on the HO it might not be as dramatic, but should be good gains.

I would think a cam/exhaust 305 could hang decent with an lt1, but IMHO theres no way you're going to get anywhere near that ls1 lol.

i have a 99z28 with hooker lts, aerochamber 3", and an MTI lid...it will destroy my 87 no contest...

...anywho, expect some nice gains, and have fun!

 

Lol, yeah, his ls1 is bone stock and runs 8.6's all day long with drag radials and no stall. My other buddies lt1 run's high 8's on street tires and long tubes and full exhaust. I'd like to hang with a stock ls1 without heads, superchargers or nitrous. I do have a set of world sportsman heads and a 100 shot in the works tho. That's another day tho. I'm hoping that 116K mile cat has been restricting me =)

 

I was jw cause best ive run in my 82 (specs in sig) was a 9.7 but i ran the same mph as you. Although lol i found out later that my dizZy was off a tooth making the timming too retarted and running a stock converter. Got all the timming and carb bugs tuned out now and new stall going in this weekend hopefully ill be in the high 8s. Id take a good timing light a vacuume gauge jets rods ect whatever you need and hit the track and do some tunning.

 

Yeah, I have a decent timing light. I'm afraid to go over 12 degrees advance tho. Not looking to destroy my motor. I can't spin high rpms either. The red line starts at 5K according to the tach. I usually shift it at 5500. 6k is it's max due to the valves floating.

 

Get a advance recurve kit for the dizzy too and experiment will diffrent springs. Id say with a stock cam thats about as high as you should take it. I shift mine at 6k but ive got aftermarket cam and springs. I also found out recently that my throttle cable is too long causing me to. Not be able to go wot lol this thing should be a rocket next time at the track.

 

Lol, throttle cable being to long could pose as a problem.

 

Yup i always wondered y this motor felt stronger in my 86 (heavyer and 2.73 gears).

 

You will never catch me with that slipping clutch. If you start getting close I will have to do something to my Formula.