I am looking for some advice. First background, all NA.
Car is mainly used for road racing, very little street driving. Weighs 2700#s, T56 Magnum with 8.8 IRS 3.55, roughly 25 inch diameter tires.

Engine, '04 pull out of a GTO, LS6 intake, SD tuned, I refreshed the 241 heads with new PSI 1511ML springs, push rods, trunion kit, added the cam mentioned below, Cloyes timing set, Melling high pressure oil pump, LS7 lifters/trays, and oil pan baffle, injectors, etc... I have accusump and oil coolers too.
Around 380hp and 360tq, don't have the sheet in front of me.
Cam is: @.050 intake 226 exhaust 232 Lift intake .537 exhaust .542 LSA 114 +2
.006 279 285
Valve timing if it matters to anyone @.050 INT 1 BTDC 45 EXH 52 BBDC 0 Specs installed at 112 per cam card. I installed the cam straight up.

Anyway. Those new parts only have around 1000 miles on them if that. I seem to have a balance issue and had to take the engine out and I am not going to mess around. Have decided to go stroker - 383, willing to upgrade heads, prefer PRC due to cost but not sure which ones make sense. Will run 93 octane. Should I swap the cam as well? I want to stay lower lift due to the beating the the valve train takes. As for power goals, can't say I truly have anything specific but figure the stroker and heads will be a nice bump regardless, just want to make sure the cam would be up to the task. Have been reading... Saw mention that strokers like tighter LSAs but then that good flowing heads don't require them. Looking for advice on cam, heads, reuse any of the newer parts?

 

Where are you located? I know where there is a really nice, never cranked Scoggin Dickey 383 with PRC heads and MS3 camshaft. 😁

Really though, make sure your vibration issue is not the clutch. I went through the same thing a few years back. After an engine swap and the vibration persisting, I changed out the Spec clutch for a LS7 unit and boom, no more vibration issues. Spec basically told me that I was full of it because they have never had a balance issue with a clutch....OK?

 

I am near Pittsburgh, I already dropped the engine off at the machine shop though. The flywheel I had replaced but the LS7 clutch that was in it didn't look bad at all so I left it.... And with my car it's actually easier to pull the engine and trans together to replace the clutch so figured I am going fix the bottom while I am at it. I am going with an ACT dual this time with their prolite flywheel.

 

Hey bud. 383 guy here. There's mixed thoughts on going 383. I myself am happy with my motor & it's performance. One thing I thought to relay to you. When I was choosing a cam for my 383 low lift was wanted for longer valve spring life also. When I spoke to one of the cam gurus he told me it isn't lift that trashes springs faster. The ramp rate of the lobe is what will cause more wear. More aggressive ramp rate less spring life. I had him spec me a custom cam. The lift is .637"/.620. To use your heads to their potential they need the valve lift.

I always think it is a good idea to talk with cam grinders/gurus, give them your info of combo & what you want, and have them spec you a cam. Rather than just picking an off the shelf grind. There are some good shelf grinds out there but would rather have a cam that was made for your motor/combo & your goals. Good luck man.

 

I do know the cam I have is the least aggressive comp grind. And I have been thinking about speaking to one of the gurus, just no idea which one yet. But thought it couldn't hurt to ask here either, seems to be a lot of knowledge/experience on this board.

 

My .02
As light as your car is unless you can put at least a 295 section width tire at the rear a well
built 383" will just blow the tires away from the low end torque and run out of steam
about 6000 RPM depending on intake runner length, talking composite (not MMS MSD).

Food for thought, I would keep your crank & rods if still good, maybe upgrade the pistons
and put the money into MamoMotorSports (MMS) 223 Sportsman Cylinder Heads
set up for Cam Motion Low Lash Solid Roller (LLSR) something "Like"
233*/239* (HR equivalent ~227/233 adjusted for lash) 114*+3* ~.620"/.600",
FAST 102, with 92 MM TB and VMax Spacer Ring. This combo @ 11.0-11.5:1
Comp should make 470-490 RWHP & 410-420+ Lb'.
On a legitimate DynoJet Dyno just for comparisons sake.
(I know, I know, "just a tool" lol)
Wicked Throttle response EVERYWHERE with as much Torque as you will
be able to hook up, and a much longer, and more FUN, useable power band
3000-7000.
Easy to tune, Peak HP~6500 RPM, carry to 7000 RPM with Valvetrain
Stability to 7500+, and easier on the valve train VS HR,
Check out DarthV8Rs Threads on his 347 SBE Build "Ghost Hawk" (long read but Tons of info)
and the "The Clash os the Titans" Intake comparison between the
MSD VS FAST 102 Using a LLSR.
Darth put at least 20K street miles on his LLSR with next to
No adjustment or Maintenance BTW!
"Cam Motion LLSR is not your Fathers Solid Roller Camshaft"
Good Luck

 

Depending on your horsepower goal... I've seen a 383 setup make 603 horses with ported GM LS6 heads by TEA. Motor also had a basic FAST 102mm and a hydraulic roller to complete the deal.
They also are pocket friendly compared the aftermarket heads as well....

 

Ok, let me explain a little more. If I get 430-440hp and similar tq I'd be extremely happy, but honestly not too worried either way. Just hope afterwards the new vettes don't seem quite as fast on the straights as they do now... I have large tires that are sticky with a controlled right foot, I don't launch the car, strictly for road courses. Figure 30 minutes of 35-160mph pulls between braking for 30 minutes to an hour.

I am not running cats, I have 1.75 inch headers into a 3 inch Y to a muffler that I know has done 500rwhp. Not worried about sound or drive-ability but I do have power brakes so I need enough vacuum for those to work.

 

Go with the setup I mentioned above. To get what you want at the rear wheels you'll need around 530 at crank which is easily done with a good head and cam package on a 383ci.

 

Installed a Spec clutch about 3 year ago. It had a vibration that while wasn't really bad it was annoying. I replaced it with an LS7 clutch and flywheel. It was extremely bothersome that for those last 3 years my 6.0 01 2500 was more comfortable and smoother that my car. No vibration and I don't have to put it in neutral at stoplights anymore.

 

Bobby Stipkovic at Steel City Auto in Pittsburgh has a stroker assembly and block for sale from a customers car. Give him a call. Might be able to save some money.