455 stage 1 valvetrain question

Hey guys, I'm finally getting around to rebuilding and restoring my 70 stage 1 convertible and I'm set on making it 100% as close to original as humanly possible. I've been searching but I cant seem to find any info on the valvetrain so my question is : is there a difference between the base/gs and stage 1 valvetrain besides the valves (rockers, lifters) or are they the same? Thanks

 

I know the springs are stiffer but wait till the Stage 1 experts chime in with all the info..

 

Here is the info on the performance upgrades taken from the Stage 1 Registry. The valve springs were different.

From a performance aspect, the stage1 option consisted of larger valves in the heads (1970-up 455 engines only: intake valves increased from 2.00 to 2.125 and exhaust valves increased from 1.625 to 1.75), stiffer valve springs (used a dual spring setup), rejetted carburetor, recurved distributor, special high-lift camshaft, high-volume fuel pump, different oil pump spring, bigger oil pickup tube diameter (for 1969-1970 only, starting in 1971 all 455s had a 5/8'' OD tube), heavy duty cooling (7 blade fan), special TH400 transmission (if so equipped - see below for details), and a positive traction (posi) rear. A 10-bolt posi rear was standard for all years, with rear gear ratios of 3.64:1 for non A/C cars and 3.42:1 for A/C cars in 1969 and 1970. Starting in 1971, all stage1 Gran Sports received 3.42:1 rear gear ratios. While not the norm, it was possible for cars built at a GMAD plant (like Framingham MA) to have received a 12 bolt rear from the factory. If a rear was needed to keep the assembly line moving, the line workers used what was available.

 

Wonder what gears came if the Framingham MA had to be equipped with a 12 bolt?

 

Thanks a lot for the help. I'm in the process of trying to hunt down the correct parts and want to be sure before I buy anything.

 

TA Performance sells a 70 Stage1 direct spec cam..

 

Yeah I spoke to them already about that. Just looking for valvetrain stuff right now.

 

You might try contacting Richard Lasseter of the GSCA. He has been able to get accurate original and repro Stage 1 parts from time to time.

 

Thanks for the tip, I'll have to check into that. Is there by any chance, a thread or a website that has factory part numbers listed for each model year?

 

I also noticed while doing some research that aside from the valves on the stage 1 heads being bigger, that the cylinder head casting around the valves is slightly different. Is this accurate or perhaps just a fluke or am I looking too much into it?

 

Thanks for all your help. I'm currently looking for 1 cylinder head right now. I have 1 already but now I know it's not a stage 1 head, but a '70 455 head.

 

Stage 1 valve springs were never "dual" springs. They were single springs with a damper and were higher pressure than the regular 455.

 

If you need help with your motor contact Jim Weise. He owns TriShield Performance and is an expert on rebuilding Stage 1 Motors. He has access to the parts that you need. Jim started this board and is a great guy. He is currently rebuilding the stage 1 motor for my 1970 Stage 1 Convertible. Good luck with your car. We all look forward to updates.