Does Anyone Know The Correct Casting Numbers For The '68 Through '72 Stage 1 And Stage 2 Hi Perf Cylinder Heads?
Someone will chime in here shortly w/ some addtl specifics, but there was the Stage 2 head that was released briefly in 1972 or a little later, so it did not exist prior to that (the casting mold cracked and was not replaced, so only a very limited number of Stage 2 heads were sold through the Buick Dealer parts network and others earlier given to Buick racers through the Buick R&D "back door"). The Stage 2 package existed as early as 1968 (I believe) in Buick parts book and was a package of parts (cam, pistons, carb, timing, etc.) minus the heads. The most famous Stage 2 package revolves around the Stage 2 heads as development work on better flowing 455 performance heads continued circa 1970-1972. I thought the Stage 1 heads (as a unique part) first appeared on the 1969 Stage 1 GS 400 model and consisted of regular heads milled or unshrouded to accept slightly larger valves better flowing). Ditto for 1970 - 1972 for the new 455 engine, meaning, the Stage 1 heads for these years were the same production 455 heads opened up (unshrouded) for the larger valves. Therefore, the Stage 1 heads had the same casting numbers as regular 455 heads and were machined for the larger valves without any further identifying numbers. So, you have to measure the valves to be able to tell if the heads are Stage 1 or not (and, I would verify the mill work unshrouding or relieving the areas around the valves to make sure some machine shop didn't later do half of the conversion). The other way of saying this is any BBB 455 head (let's say for 1970-1972) can be readily machined exactly like the factory did to achieve "Stage 1" status, again with the heads bearing the same casting numbers. (You may want to research the benefits of certain 430 heads (by casting numbers or by vehicle) as they flowed about equal to or better than the un ported Stage 1 heads) The Stage 2 heads are a totally different animal ... huge round exhaust ports the size of raquette balls. There were a few variations in the intake sides, but make no mistake about them, you cannot mistake a Stage 2 head with a Stage 1 because the exhaust sides are sooo different between the two (and, there are other technical differences, too). That said, do a search on this board for 455 head casting numbers and there will be many, many results by individual post, or by thread title (with many posts inside the thread). Hope that helps. Ken
I would add more comment(s) to the above post in that a lot more info about Buick using "Stage 1" heads on different models has become known. Since "Stage 1" modified heads had the same casting numbers as regular production 455 heads, identifying them is problemmatic because the heads have to be off the engine. This fact that Buick did indeed build many, many different 455 engine combinations OTHER THAN the Stage 1 engine/package in the GS/Gran Sport series. Yes. Learn to call these "Stage 1" heads "Big Valve" heads and also understand that the big valve/Stage 1 heads were a part of (albeit and important part) of the Stage 1 performance option (in the GS = big valve heads, distributor, carb/jetting, timing, camshaft, etc) and you will learn that you have far more parts sources for Stage 1/big valve heads because the same big valve heads were put on the '70 Riviera GS 455 (but not the std. '70 Riviera 455), some '71-'74 Riviera GS's, Centurions and (I think LeSabres & Electras) with a 'W' in the VIN denoting the "hi-performance" 455. These engines did not have all the other specific Stage 1 package parts like the formal Stage 1 package in the GS series, but they have the big valve heads. Then again, remember that virtually any qualified machine shop can convert 455 heads to Stage 1/big valve specs ... and there are many very, very good Buick shops affiliated with this board that do this conversion every day and use the latest developmental research results for the Buick 455. IMHO, the 455 engine is somewhat unique in its building requirements (critical clearances and oiling requirements) that so many Chevy & Mopar based engine shops and people don't really understand or have to deal with in the same way.
