[Blake1983]

hey guys new here and figured i'd post here even though i have an older mustang - 5.0 guys tend to be more in tune to my tastes rather than the "Classics" guys.

first off i own a 1968 mustang with a 331 stroker.

right now it's running 12.2's @ 109 mph but i feel it's got more in it, that something isn't right.

i can't get off the line at anything over 1000rpm because the tires just light up for one thing, 2.. the car feels "flat" for lack of better explanation until around 3k and it "clears up" and takes off.

also had a question about timing, exhaust for the track and tire pressure.

right now we're running at 36 degrees total with a base of 12 (24 in the distributor limited) with it all in at around 3000. I'm running BFG 275/50/15's in the rear at 17-18 psi (others have told me to run as much as 25psi) i've ran as low as 10 and get the same results but with the car getting a little wobbly at the top end. i pull high 1.8 60's.

for the track i'd like to run open exhaust - right now i have 2 1/2 " straight pipes to flowmaster 40's with dumps for cruising - and i've seen numerous "pipe" lengths for running off the headers. someone suggested to run a 3" pipe off each header for about 18-20" and that should be optimal, anyone have any input?

as for the setup of my car here is as follows, any help would be greatly appreciated - thanks!

331 stroker w/ scat forged crank / forged rods / Keith black 11cc dished pistons which are giving me around 9.5-9.6:1 compression (had to be gas friendly)

Edelbrock Performer RPM heads (no smog, 1.94/1.60 valves)
Weiand X-Celerator Intake manifold with a 1" spacer blended in
Comp Cams XE276HR with Trick Flow 1.7 Roller Rockers
Holley Street Avenger 670 CFM with no choke horn
(carb is set up with 71s in the front - 78's in the back, 31 squirter with a blue pump cam in the #2, with the lightest secondary spring)
Hedman 1 3/4" longtubes
Pertronix Flamethrower distributor w/ MSD 2 coil w/ MSD wires
Autolite 3924's @ .037 gap

i also run an Electric fan, no power steering, no a/c

i have a professionally built C4 trans with a custom servo, manual valve body etc.. and a 2800-3000 stall converter with a B&M star shifter throwing the power through an aluminum driveshaft to a 8.8" rear with 3.73 gears.

for suspension i have 4 leaf rear springs with the smallest leaf removed - 1966 V8 springs on the front , traction master traction bars (not slappers)

so far as i've said best to date is a 12.221 @ 109mph with a 1.8 60' time launching off idle (cus i can't at anything else due to smoking up the tires) shifting at 6000 rpm's and going through the traps at around 5800-6000

[88-gt-t-top]

What Diff. do you have in the rear-end? If it's an open diff. thats a problem. Are you warming up the tires before you stage? I would run them anywhere from 12-16psi. Those are my thoughts. This would be a possibility, but then again i'm not 100% on this, but maybe thats too much cam? thats why it's not picking up until 3000rpm? Hopefully you'll get some more input from the other guys.

[93hatch]

slicks

[88_FiveOh]

I have Mickey Thompson ET streets and i run them at 12psi and dont have a problem hooking up. Also i agree with the post above me on the rear diff.

[Blake1983]

as stated it's an 8.8" swap with brand new carbon fiber clutch packs (yes, 8.8".. it's out of a 98 gt)

[93mustank]

You need to change : Heads,cam, intake , gears and converter ................

[Blake1983]

Originally Posted by 93mustank You need to change : Heads,cam, intake , gears and converter ................

heh, that's kinda funny. :|

[88-gt-t-top]

Originally Posted by Blake1983 as stated it's an 8.8" swap with brand new carbon fiber clutch packs (yes, 8.8".. it's out of a 98 gt)

O.K. well i don't know what kind of differential comes in a 1998 GT rear end. Are you able to do one wheel burn outs, or do you leave two tire marks when burning out?

[Blake1983]

8.8" traction lok - and no, i don't do one wheel burnouts, that's why i ditched the stock 8" peg leg simply for the reason it's drag raced.

[Blake1983]

dyno'd and tuned it today, was a little off on the jets in the rear, was running rich @ 11:6 A/F due to having 83's in the rear - swapped out for 78's and went to a 12:7 and made the most power, also fixed the dead spot i had. tried a few things with the timing, had it originally set at 36, tried 38 and lost 10 hp, put it to 34 degrees and gained 7 hp over the initial 36.

it did alright - dynoed in at 347 rwhp - couldn't get a torque reading due to the software used and my car being old so they couldn't get the rpms to get the torque. guessing it's around 360-370. this was on a mustang dyno with the WCF numbers. all in all i'm surprised.. now to just get the power to the ground