Got a set of Riv heads at home and was curious if they might have Stage valves. I suppose I could just measure them. What would stage valves measure out at? - Freed
If the intake and exhaust valves are almost touching, then you have stage valves. If there is over 1/8" space between them, they're standard.
Steve for a couple of years I think they called it" high performance" and then went back to the stage 1 name once again at the end of production.
No special markings. Just normal 455 heads that were resized for larger valves. Like the above post, just look at the valves if the heads are off the engine. The intake and exhaust valves almost touch. Should be just enough room for a dime to fit in between the vavles.:Smarty:
Here is a picture of my heads when I had them rebuilt last summer. Note how close the valves are together.
Hey Martin, those look like Stage 1 valves to me. I'm no expert. look here for some closeups. The combustion chamber even looks the same. Click Me
Yep, they're stage1's....originals from my Centurion. It has the optional "hi performance" 455 that Jim Lore spoke about in one of the above posts. I just posted the picture to show what the stage1 valves look like. I had forgotten about the pictures on BuickPerformance.com! They have a great comparison page...
If the heads were still on the car, you can guess correctly about 80% or so of the time. For 1970, there was only one engine available (the GS package did not change the engine). They all had the larger valves. Starting in 1971, the base 455 was the standard engine. The GS package generally meant the larger valves were included (there were more than a few mistakes made on the assembly line, though). I don't remember for sure, but I think 1974 was the last year for the larger valves. There's a different performance range, which is why they preferred the regular valves in most of the cars. The regular vavles performed a little better in the low end for standard driveability. The larger valves shine in the upper performance ranges.
Well, I don't think mine are HP heads. They are from a 73 Riv. I bought the whole motor and the heads are off the block. I measured the Intake on one of them and it was 2", not 2.125" The intake and exhaust are pretty close together, but not THAT close together. Thanks to all for the education. - Freed
Riv GS and Centurion had an optional "hi performance" 455 which was SUPPOSED to have stage1 heads, but some have been found without big valved heads, when they were supposed to have them from the factory.
