Hi, this is going to be a little on the long side so please excuse. I made my first runs after a number of mods to my 83 TA (LG4, 5spd). My quickest run was 15.81(86 MPH), while another more experienced driver managed to get a 15.66(89 MPH). 60ft times were 2.3 roughly for each of us with his being slightly lower. To be honest I was expecting a little better with all I've done to the engine(really hoped to get high 14's or very low 15's. My mods are:

Edelbrock Performer Intake and Qjet (#1901)
Heddman headers(1 3/4) & Y pipe
14-inch Catco cat, Dynomax cat-back exhaust (2 3/4) intermediate pipe.
Comp Cams 268H
Accel Blueprint HEI
Stock heads rebuilt, mild port & polish, Edelbrock Performer valve springs, new rocker arms, push rods, fuel pump.
5spd w B&M Ripper, 3:73 posi rear, 16x8 wheels with Z rated tires(245/50/16).
Dual snorkel air cleaner, also retained the cowl induction lid.
Computer has been disconnected and all smog stuff removed.

So, are those times what one would expect with the given mods? If they should be better what could be off? I'm thinking the headers could be part of the problem as I think they are too big. Any advice or comments???

[This message has been edited by TA76 (edited August 27, 2001).]

 

You're right, the car should be quicker than that. I don't see anything really wrong with your combo, though it might be a little faster with smaller headers, and that's not the fastest possible carb (its virtues are driveability and gas mileage more than max power); on the other hand, that cam would move the power band of a 305 pretty far up, so maybe the motor ought to be able to take advantage of the bigger headers.

I'd guess the bottleneck is the heads. Still, a stock L69 off the showroom floor did basically a 15 flat, so there's plenty left on the table in your case. There's some tuning you should do first; check you timing curve, it should be about 10-12° static, then make sure you get about 38° of total timing, with it all in by about 2800 RPM. Your 60' times are another clue to the matter: you should be able to cut that down to 2.0 with better tires and the right suspension work. Your 89 MPH run should go with nearly a half-second lower ET, so it looks to me like you have serious traction issues.

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"So many Mustangs, so little time..."
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RB83L69, once again I'm in your debt! I suspect your timing advice will cure a great deal of my problem. If you recall, you gave me some advice earlier on reseting the timing because my timing cover is wrong. I've yet to do that as I'm afraid of screwing it up since it is running fairly decent.

One more thing, I may have the model number wrong on the carb. It is a 750cfm Qjet not the Carter AFB/Edelbrock unit.


[This message has been edited by TA76 (edited August 27, 2001).]

 

I don't know man, I think your mph is a bit low with that combo. I have an 84 L69 with headers and a performer RPM (stock heads and cam) and I get 93.5 mph. With a 2.1 60ft I run 14.6. Are you sure your carb is setup at WOT properly? Also that 268 cam is pretty big for a 305 are you shifting it high enough?



[This message has been edited by Cosmik Debris (edited August 27, 2001).]

 

Every tenth you leave in the 60 ft time is worth 2 at te big end of the track at that power level. In other words, if you get it to launch you're in the low 15s no problem.

MPH is a little low, but that will pick up some with a better lauch (note your friend picked up 3 MPH with a 2 tenths better ET).

Still seems like you should be running a bit faster.

 

I see you are in Alabama. Did you correct your ET for climate and altitude?

You will go much faster at 60* than you will at 90*.

 

Thanks again for the advice guys. I've been told the 268H is a little on the "big" side for my 305 but it idles pretty decent. You don't really even notice any kind of lope to it. I also need to check the carb as suggested to make sure it is opening all the way. And YES it was a hot one this weekend, a sunny/humid 96.

 

Well, as the Dixie Chicks say "There's yer trouble."

A humid 96 degrees will many anything droop. Expect way better times when it isn't the height of summer.

 

I was able to get my 86 5 Speed LG4 T/A to run a 14.94 @ 91.67mph.
This was with an Edelbrock 7101 Intake Manifold, Edelbrock 1406 Carb, Edelbrock open Element air cleaner, MSD HEI Coil, and a flowmaster muffler with stock intermediate pipe and exhaust manifolds.
I had consistant 2.1 60ft times.
My very first run ever on a drag strip I ran a 15.12 @ 92.80mph.
I had 130K miles on the motor, so there is definately something amiss with your setup.

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