No one can give you a truley accurate answer with any proof to back up there answer on the internet. You will have to check this your self.

Look on Reher-Morrisons website under tech-talk they have a very good write up on how to check it properly, and it is very simple.

 

Yes, I had that feeling, but thought I'd at least ask. Sounds the the 355 is a safer way to go for him.

 

the PTV clearance will be the same with a 355 and a 383 as the piston will just drop farther in the hole with the 383.

there will not be any machining needed to realign the intake if he is reusing his old heads and intake.

I am running a 246/254 .613/.590 112 on a zero decked block and 48cc combustion chambers.

the 306 should be fine with what you have.

 

Except for you do not know what velve heights he has in the chambers, or how much spring he is running which can cause valve flex ect...

Yes I agree he SHOULD be ok, but there is only one way to be sure, and if your wrong the money spent to rectify the situation would far surpass you budget constraints.

Won't the piston dwell at TDC longer with a 383 as well?

 

Hello my names Alex over @ QTP. I'm the guy running into this problem in trying to figure out what to do with my motor combination. I just thought I would throw out the specs on the top end of the motor.

I got the heads from Brian ProjectZ28. They were ported by Jason Short in NY. they were completely broken down by my machine shop. They flowed right around 255cfm at .500 lift. Chambers are 54cc's, valve springs are comp 977's with Ti retainers and locks ARP studs and Comp 4084 guide plates. Before they were put back together the valves were lapped and seats cleaned up. I don't know what the installed height of the springs are off hand. I belive they were set up at 1.800 so they should be good for .600 lift. I'm using Mr. Gasket .026" gaskets. The intake was also ported by Jason Short. Nothing real fancy just a basic port job on the runners and the TB was opened up to 58MM. Finally the cam is a Comp Cams "306" LT1 Camshaft, 230 / 244, .510 / .540 112 LSA
-Comp Magnum 1.52RR
-Comp .0072 Chromemoly Push-Rods
-Stock Lifters
-Comp 977 spring
-Comp Ti +.050 retainers/seats/locks
-ARP 7/16 studs
-561 casting heads flowed @ 255cfm @ .500 lift
*54cc Chambers
-ARP Head Bolts
-Racetronix 255lbhr Fuel Pump & Hot-Wire kit
-Lunati Double Roller Timing Chain
-Port Matched LT1 Intake with Ported Runners
-GMPP EGR Block-Off plates
-Enlarged Throttle Body Opening (sized for 58mm throttle body)
-Stock ported Throttle Body
-Meizer Electric Water Pump
-!AIR/EGR
-Throttle Body ByPass

 

with the 306 and stock CC combustion chambers it would shock me if you had PTV issues unless you are running a dome piston

I am running 13* more intake duration and 12* more exhaust with 6cc less combustion chamber, with no issues.

I am currently running 12.2:1 on pump gas car has 15-20K miles on the current motor