Went back out to the track tonight. I was just playing around on street tires so I don't car too much about my e/t. But my mph seems low for the motor to me.

357 eagle forged, flat srp pistons
12:1 compression
gm847
stock heads, 2.00/1.56 valves, 3 angle job, mild porting. Peak numbers were mid 250 flow on the intake
getto cold air, home made stock TB, ported intake
hooker long tubes, h pipe 2.5" duals, 40 series flowmaster x 2
6 speed + 10 bolt

best of the night was @ 12.809 @ 111.69 w/ 2.1 60ft.

I realize once I get my rear end / tires / supspension that thats enough to carry me to low 12s, however I really think something is missing. Also I probably need some more tuning as this is my pcm4less mail order tune for my cc306

 

Your exhaust setup looks fine.

 

I just feel that even for mild heads my traps are low. Would a better 60' and better shifting (spinning on 2 and 3 shift, scratching 4th) impove my mph?

I was hoping for @ 115mph.

 

How high are you reving it? with that cam its gonna want to rev to make power.

 

Shifting 6600-6700. Limiter is at 6800 and I did hit it on a pass or two.

Motor would take higher if I need to spin it higher, guess its dyno time.

I have always heard bad things about flow masters, but usually its people talking about the 80 series. If my 2 40s aren't hurting me I will just let them be, allthought I was looking at some sweet thunder 24" ones.

 

dude I'd think from what ive seen posted on here that an 847 and mild heads would be good for high 11's

 

getting close to a 1.6-7 60' foot would put you in the 11.9-12.1 range

 

I think that exhaust is more than addequate. I believe there is a little in the tune. Not too much but some. Is the tune set up for 12:1 compression?

 

I highly doubt your exhaust is slowing you down. Flowmasters flow rather poorly, moreso on the crossflow type mufflers....however with 2.5" true duals they flow more then enough for your setup. You may gain a small amount by swapping them out, but probably not enough to make it worthwhile.

 

Your times seem really low for your set-up. I have stock ported heads, stock valves, full bolt ons, 233/239 cam, full weight, true duals 2.5, slp headers, and a forged 355 with about 11:1. I netted a 12.1 @116 with a 1.9 short time. I was spinning off the line. If i woulda hooked that pass it woulda been a 11 sec pass easy.

 

I made 1 street tire pass in the 94....it went 12.94 @113 on a 2.5 60' (26" tires and 4.10 gears)
on slicks it went 11.6 @ 119 (28" tires and 3.73's)....it would trap over 120 on the 26's

with sticky tire and a better launch I think you will find your missing MPH

2 things that will also affect trap speeds are density altitude and raceweight

 

Shes fat, 3710 with me. And just re adjusted the valves, a couple were overly tight. Seems to run a bit better now. Dyno scheduled in 2 weeks. Will report back.

 

Hey jsetzer, you don't happen to live in OK, do you?

 

Sure do, and I happen to know of a little red SS that came to visit me years ago.

Going to the dyno on Wed... if I can't find my missing power Ill just spray the damn thing.