Valve / Piston Clearance in 383

-
I have the same pistons and I have a 519/260 Comp Cam.I think some head work will really help you out.
 
Yeah, I think I get the rear end sorted first and take it back out and tune it and then give the heads a clean up..
 
I didn't read every word of the last 3 pages, so if I am repeating any info, I apologize. I have a 383 in my Barracuda with the stock style no valve relief pistons. Mine sit .020" in the .030" over bores. I have a lightly milled set of "516's", with 2.08/1.74" nail head valves. (the nail head style reduces combustion chamber volume). I can't recall what they CC'd to, but it was less than many report. With a composite gasket, my compression is at 9.97 to 1. The cam is just a Summit .465/.488" hydraulic with stock rockers. RPM intake, 750 DP carb with a Proform body. Race weight is about 3,300 pounds. I have a major issue with something, it won't make power past 5,000 rpms. Even so, it ran a 12.4 et the third pass at the track. Your combo should be making at least 450 HP.
 
Ive started another thread on here with my driveline specs outlined. Yeah I wouldve thought Id run a high 12 but not the case. A few things I will need to check out as well.
 
BBBCUDA said:
I didn't read every word of the last 3 pages, so if I am repeating any info, I apologize. I have a 383 in my Barracuda with the stock style no valve relief pistons. Mine sit .020" in the .030" over bores. I have a lightly milled set of "516's", with 2.08/1.74" nail head valves. (the nail head style reduces combustion chamber volume). I can't recall what they CC'd to, but it was less than many report. With a composite gasket, my compression is at 9.97 to 1. The cam is just a Summit .465/.488" hydraulic with stock rockers. RPM intake, 750 DP carb with a Proform body. Race weight is about 3,300 pounds. I have a major issue with something, it won't make power past 5,000 rpms. Even so, it ran a 12.4 et the third pass at the track. Your combo should be making at least 450 HP.
Click to expand...

Sounds like you need to post a thread with your problems and observations if you haven't already...but I'd initially ask, what does it do above 5k?
 
txstang84 said:
Sounds like you need to post a thread with your problems and observations if you haven't already...but I'd initially ask, what does it do above 5k?
Click to expand...

Not much about 5,000. Peak power is at about 5,200. I had it on the dyno ages ago but might put it back on for a tune.
 
txstang84 said:
Sounds like you need to post a thread with your problems and observations if you haven't already...but I'd initially ask, what does it do above 5k?
Click to expand...

I don't want to step on Panas thread, but I believe this question was aimed at me. The short answer is : "It goes slower". It will happily rev to 6,000+, but it slows down. I have always heard fastest ET usually comes by shifting 500-1,000 rpms. past peak power. If true, this thing is flat on it's face at 4,500 rpms. or less. That is about what my 9.5" converter flashes to, so that seems like a very poor match. I've tried 2 different ignitions with no change, it currently has a full MSD set up. Fairly substantial jet changes at the track resulted in basically no change. My next change was to ditch the cam for the old .528 MP solid with some iron Isky rockers.
 
Ooops! Youa re correct! I totally misread it..

BBBCUDA said:
I don't want to step on Panas thread, but I believe this question was aimed at me. The short answer is : "It goes slower". It will happily rev to 6,000+, but it slows down. I have always heard fastest ET usually comes by shifting 500-1,000 rpms. past peak power. If true, this thing is flat on it's face at 4,500 rpms. or less. That is about what my 9.5" converter flashes to, so that seems like a very poor match. I've tried 2 different ignitions with no change, it currently has a full MSD set up. Fairly substantial jet changes at the track resulted in basically no change. My next change was to ditch the cam for the old .528 MP solid with some iron Isky rockers.
Click to expand...
 
I would suggest either some aluminum heads or porting yours to wake up that engine. Then- try a bigger cam (510 Comp Cam).
Out back- try adding a half-spring on the right front spring section, clamping it and the rear portion as well. Plus- get that Duster aligned with you in the car as weight & open the door when setting it (old racers trick). How about the front shocks? 90/10's? My 2 cents. I'd bet $$ your car runs a flat 12's after all this!
 
chrisnben said:
I would suggest either some aluminum heads or porting yours to wake up that engine. Then- try a bigger cam (510 Comp Cam).
Out back- try adding a half-spring on the right front spring section, clamping it and the rear portion as well. Plus- get that Duster aligned with you in the car as weight & open the door when setting it (old racers trick). How about the front shocks? 90/10's? My 2 cents. I'd bet $$ your car runs a flat 12's after all this!
Click to expand...

Have no idea what shitty shock absorbers I have on the car? They were what was originally on there. Just OEM Gas Shocks I think. So 90/10's on the front and just leave the back as is? Definitely have to get a wheel alignment. I got my SS springs delivered today so they should help. Hopefully over the winter (Aust winter) I will get the heads off and do some porting and clean up work on them and throw a bigger stick in there as well...
 
with SS springs mate, you WILL need longer rear shocks. Don't forget to clamp them up too. Now let's see some wheelies!
 
Pana.Mopar said:
Will do. Got a pair of 90/10 front shocks as well. Should help a fair bit.
Click to expand...

Hello man,been a while... S/S springs,need an extended shock. Try a basic 70,71 Imperial basic gas cheapie shock. It's that simple.
 
along with rumblefish's reccomendations, i'd add

carb jetted/tuned for combo ... if it's very used it may need a rebuild, if it's out of the box it probably could use some mods to match the engine.
put car on a diet (lose some weight) - lighter wheels, remove everything from the car you can for race (spare tire, etc)

also what air cleaner are you running?
 
moparlover said:
along with rumblefish's reccomendations, i'd add

carb jetted/tuned for combo ... if it's very used it may need a rebuild, if it's out of the box it probably could use some mods to match the engine.
put car on a diet (lose some weight) - lighter wheels, remove everything from the car you can for race (spare tire, etc)
also what air cleaner are you running?
Click to expand...

Carb was rebuilt long ago. It's an older style 4779. I'm running K&N open top air cleaner.
 
You must log in or register to reply here.
-

Back
Top