Best e.t to date is 13.19 @ 107mph. This was last sunday where I was cutting very consistant 2.0 60'. A couple of weeks prior I was running a best of 13.23 @ 109mph w/ a 2.4-2.5 60'. This is what really confuses me.

Mods are as follows: forged 383
-P&P heads w/ 2.02, 1.60 valves
-236/242 comp cams w/ 1.6 Pro Mag RR's and Comp R lifters
-The only bolt-on I dont have is the long tubes awaiting install but I am running a set of shorty headers with a Borla
-Mad Z tune
-Stock rear end
-Stock suspension as far as drag racing i.e. no aftermarket lca's or torque arm

Any suggestions? I pretty sure gears are hurting my times...but that bad.

 

Get to a dyno. Something definitely isnt right with your setup.

 

Thats where it gets even better. I have been to the dyno
337 hp and 347 tq.

 

Your mph is pretty weak for a 383 car. Very very weak actually. I was running around the 106 mph area when I was bone stock (motor wise), and with my current 383, I'm around 115 to 118. Don't worry about the ET for now. Concentrate on getting some power (MPH) out of that thing first

A few questions and maybe we can narrow this down a bit...

Did you have the heads flowed to see what you have to work with?
Did you build the motor or did someone else put it together?
What kind of compression are you at?
Have you scanned it during a run to see what the codes look like? (knock count, MAF flow, etc..)
Are the lifters adjusted right? (the Compr R's are notorious for being a pain to get right - it's very easy to go too far with them)
What kind of trans and how old is it?

Throw us a bone and maybe we can help out some

Dave C.

 

Looks like you are doing something right, you dropped nearly a .5 second
on your 60'.

Although, your E.T. did not drop much. Also your trapping slower.
Looks like you might be down on some power for some reason.

 

No big deal man, its probably something fairly simple I bet. A basic mail order tune will still run fairly decent. My guess is you are seeing 10*+ KR at WOT and thats just killing the performance.

 

Get the Long tubes on and retune the car .. What gears do you run? Do you run the borla plate system? What was your A/F on the dyno? What is your elevation at the track and dyno?

 

You're definitely losing power somewhere. The first place to look would be the heads - what work was done to them? Flowed? Get the thing on a dyno and scan the runs to see if you're car is breaking up (ignition or valve float, or ?). Not trying to make you feel worse than you do, but my CC305 cammed, 350 ci, stock LT4 head car ran faster and made more power.

Start with one thing at a time.

 

scan it with datamaster and send it to me. vincentbergeron@yahoo.com

something is not right and i bet its simple

 

Are you running the stock fuel pump? if so that maybe holding you back.

 

Okay let me see if I can answer everyones ?'s
- stock 3.42 gear
- T56 with 155,000
-stock fuel pump but pressure is still above 40 and hits 45 or 46 on WOT also 30lbs inj that only max out at ~78%DC
- laptop I was using to scan and tune **** the bed for now, working on getting it fixed
-heads were not flow tested because they wanted $25 a cylinder; couldnt swing it at the time
- I figure compression to be about 11-11.5:1. The SRP pistons were 10.5:1 with 58cc heads and I went off of the stock value of 53.7 cc I read somewhere and comp cams telling me about 6 cc = 1 point of compression roughly
- I built the motor myself with help from the guy who did the machine work. I have built a fews motors before so I had a good grasp of what I was doing
-If I rememebr right my afg's were at around 7 or 8 at idle. Dont remember at WOT
- Borla cat-back with no plate
- I do have either valve float or a miss at 5500 rpms and up. Starts to break up bad on the dyno
- A/F was around ~12.3:1

Pulled my plugs yesterday and all are tan colored except one that smells like its way to rich and has a black tip
On my madZ tune Ion retarded the timing on WOT for a 150 shot- that couldnt be hurting me that much could it???

Hopefully I can get my laptop up soon
Thanks everyone

 

how much was it retarded?

 

He never said....I could ask him though. Whats teh avg. retard....2 or 4 degress per 100 shot

 

I would put money on you needing 4.10s instead of 3.42s being your problem.

 

Gears have nothing to do with the sub-par dyno numbers for what he has. I realize you don't race dyno's, but the output seems low to me regardless.