Well I found out what the source of my problems are. The heads that I bought aren't very good and they can't really do all that much to fix them. They told me it will still haul some ***, but I could tell that they weren't really all that impressed with the numbers themselves...

I made peak 454hp at 6000rpm, peak torque was 440 ft/lbs at 4800rpm. They averaged me at 385hp and 426 ft/lbs. They pulled the averages from 3500 to 6000. They also ran me through a dual flowmaster exhaust with 1 3/4 headers which will rob me of some power over my loudmouth, and o/r y-pipe. Also, something else they pointed out... the one guy told me they typically have a 25% loss from the engine dyno to the chassis! That's suprisingly high it seems...

Anyways, it seems my only chance at any major improvements will be to do some new heads at one point. They seem pretty confident at this point that I will at least be able to walk all over my bro's 99 cammed LS1, which they also did the work on. I have some additional numbers for air/fuel ratio as well if anyone wants to take a look.

EDIT: I also have cam specs now as well

 

sounds like very bad comunication on their part and yours,if the heads were not good as they say,why would they use them or not tell you before they use them..

 

Well, actually it's more my fault, they told me the heads were poor from the start and told me they would do whatever they could to help them out, but they really didn't have much to work with. So I'm stuck with some bad heads until I get some more cash and more patience since it's been so long since I've driven it, I want to get it back as soon as possible.

 

Let's be a little more clear, he supplied the shop with modified stock heads and the shop is telling him they are no good. I would tend to agree.

 

100% correct right there

 

ported stock castings? what, bad port job? what did they do to "help" them?

my 383 was no dynoqueen. it only put down 320 (~roughly 360 on a dynojet)on a mustang dyno. unlocked #s. but I had my own ported heads, intake, and a small 233/239 cam (small for a 383). with 3:42 gears it still went 11.68 with a 3800 stall. it also never had a good dyno tune. I had a madz28 tune that was rich at WOT but otherwise ran great. had them lean it out at WOT on the dyno but thats all the change's they made. and only 2 pulls. baseline, then one change that was it. so Im positive there was still a little more left in it w/o replacing any parts. my car is fully loaded except for ttops, and I removed the sway bar and light wheels. just to give you an idea of what a decent 383 can do in a very typical weight car. Lloyd typicalls suggests 232/23x cams for 383's. maybe he'll suggest something diff. for your car, but doubt he'll go larger if the heads port job is for shiznit.

 

They basically smoothed out all the ports to the point where it wouldn't be rough to the touch anymore and just anywhere else that needed it (basically everywhere). They didn't have much to work with either. That's nice to know that good things can still happen even when you don't exactly have the best stuff, hopefully I'll find that to be true here as well.