I was talking to John Osborne one day about Buicks motors. When the discussion of Stage 1 heads vs Big valve heads came up. He was the first to tell me about how some centrion(?)and riv's had the bigger valves ,but were not Stage 1's . Stage 1 engines had swirl polish valves and the other where consider Centurion valves that you could get thur Napa. Is this the finding of others. This may be why some riv's have the bigger valves but arenot Stage 1's unless it has the vin or Stage 1 emblem's.
"Centurion" valves, as we use to call them, where cheaper than the swirl polished Stage-1's valves and the same size. I may even have the old Buick part numbers somewhere in my old book of notes. I remember a dyno test a long time ago (in the late 70's) where there wasn't any real difference between the two types of valves on a 455 engine. The cam in that engine (Buick's big car performance cam) pulled to about 4,700-4,800 rpm only. Maybe that's why there was no difference. I think it may have been the same dyno tests that proved that a ported set of small valve heads where a cheaper and more practical solution for the big car guys that were thinking about switching to the bigger valves but not swapping out their factory performance cam. The so called big car Stage-1's had a much different engine/cam/timing/transmission calibration than the smaller GS's. They weren't the same animal, and I think it would have cause some confusion if they called both engines Stage-1. I think in 1973 they eventually did that with the Riviera. :error:
That's what I was thinking. I don't want to bust anybody's bubble who owns a big valve motor or thinks they have a Stage1 just because it has big valves in it.Stage 1 are different even in riv's. Don't know about 73's , but 70-72 are different.
It;s still cool to know that your car came from the factory with big valve heads:bglasses: especially when you weren't expecting it!! Probably one of the best surprises to me when I pulled the heads off my motor in Spring of 2003 for a rebuild and conversion, only to find I didn't need to..
I think in 73? they started calling those "Stage 1" instead of "High Performance" in Rivs and the C cars.
Smartin, I would imagine so and a great find. Flynbuick Not sure, but if it isn't v code it's not a Stage engine.
This is a new one to me. A little more detail on which model and year might have had the big valves would be great! Any way to tell by engine numbers? Just wanting to know if I have one and don't know it. I would love to find a set of heads with larger valves in them!
Hey Guys, I am looking at a 74 Buick buyers guide and it lists the Stage 1 option availabe in the following cars. Riviera,Electra Ltd.,225 and custom,LeSabre,Century(Gran Sport only). I suppose that back then you could still special order oddballs if you flashed the cash. Bill
True Bill... I heard thru the grapevine that a bunch of Electras left the assembly line with the hi-perf 455 (with big valve heads) since they were overrruns. (or didn't have any regular in stock?) Supposedly, it was really a craps shoot whether your car with the hi-perf 455 would actually have the big valved heads in it. Sometimes, I guess the workers got lazy and slapped motors together without looking closely.
Adam, Funny you should mention that rumor,I heard the same one quite a few years ago. Bottom line is if you never had the motor apart how could you be sure the assembly line guys didn't just do the plug and play. As a side note I owned an original 70 GSX Stage 1 that had a SF block designation on its paperwork,but still had Stage 1 number matching components. Talk about odd?? :error: :error: Bill
not sure what valves I got ok, i'm doing a 455 rebuild, it's a 74. Not sure what valves I got? they look big. the only thing i see stamped in them is GM and Either a T or I, not sure what it is. anyone know .?
measure the head of the valve. It should measure 2.125 on the intake and 1.75 on exhaust. Poods I think big cars with a 4-barrell and dual exhaust had them from 71-74
So, is my 71 RIV considered a Big Car? It seems to fall in the grey area in parts books. The engine runs well, so I have no immediate plans on pulling the heads to verify the valve size. Thanks
Riv is definitely a full size car:Brow: If you cannot fit anything more than a dime (sometimes not even that) between the intake and exhaust valves, then you have big valves Check this link out: http://www.buickperformance.com/455hdcompare.htm
Poods when was your 71 GS455 built? Mine was built in may 71 and came with a Stg1 engine and trans, but the rest of it was GS 455.
Never checked the date on it. It doesn't have the original engine in it, but I can say that it does have some big valves now that probably flow pretty good. :3gears:
I found that link a while back. I never knew till then that those factory stage 2 heads had such huge runners! My wife would definetely call the Riv a big car. Or, huge car, boat, barge, beast, ugly, pimp ride, P.O.S., ......... Guess you all get the ideal. She hates my old cars. o No:
I fill the same heat!! Why are buying that! You spend more time with it than with me! It's to loud! It makes my neck hurt! Slow down! Now I know why you buy tires so often! But I still love her after 8 years today! ( My wife) I have had the GS for 27 years.
So short of pulling heads I would like to know if this is fact or fiction. I find it hard to believe no one knows for sure. JP
