Stage motor in Riv?

Was the GS stage 1 motor available in the 71 Riv under the GS option or another 455 combination that provided the 330 hp?

 

HP technically because the Riv engine does not use the same camshaft.

 

So you would see the larger valves as a stage 1? What would the deck be stamped with?

 

Do not go by advertised HP ratings.

As for the 71 GS Riviera. For the 1971 and 1972 Riviera IF it is an original unmolested GS Riviera it WILL have the larger Stage 1 valves in the heads. IT WILL have a different camshaft then the standard Riviera of that year and it will also different from the Gran Sport Stage 1 camshaft. THere are NO Stage 1 emblems for these years.

For the 1973 model Riviera GM split the option in two. A: Stage 1 Option and 2: GS Option. For this year and the 1974 model year a Stage 1 option Riv will have a Stage 1 grill emblem and it is designated in the VIN.

So if you happen to come across one in a bone yard the heads will have the larger valves on GS models 1971-72 and Stage 1 Rivs for the 73-74 models. But quite frankly if you come across one I would just take the entire engine as 455 are starting to get hard to find.

 

Here is my attempt to compare the relative output of bigger displacement Buick engines. http://www.v8buick.com/showthread.php?t=143875&highlight=normalize

 

The 455's in the 1970 Riviera GS should also be a source for the large valve Stage 1 heads, but then again, a quality machine shop can also make the necessary modifications to convert standard 455 heads to Stage 1 specs as part of a rebuild ... since the heads (non & Stage 1) carried the same part numbers in any given year, so, don't buy a car just for the "rare" heads.

Question: Since the 1970 Riviera GS's got the Stage 1 heads and the 1970 GS Stage 1 (A-bodies) were only built in Flint, were the 1970 Riviera GS's also only built in Flint?

 

I have an opportunity to buy the motor out of a GS Riv for $800. I am trying to decide if its worth it to me.

 

I have parted a few over the years. One non GS 73 had all matching components. It didn't have stage 1 valves when I tore it down. Another one was a 1 owner 71 non GS. It didn't have stage 1 valves. A couple of 70 non GS Rivs also didn't have stage valves. So after reading all the posts on here about GS Rivs I was excited to tear down a 72 GS Riv engine to find stage valves. What did I find? No stage 1 valves! It was all matching #'s and didn't look like anyone had ever touched the engine.
So, I have had no luck finding stage 1 valved heads on Rivs.

 

I did a total break down on the Rivieras from 1971 thru 1975 regarding the GS and Stage 1 packages. Break down was in one of the BPG Build sheets and NE Newsletter. It is long and also has part numbers on the different cams used. It mays still be on this board if the thread was lost in the last crash. It explains things totally.

As for the '70 model year it has been a toss up on what people found. I can only tell ya about the boattails '71-'75. My sources are from the Riviera Club, BCA and Dennis Manner and various Buick parts and history/production books. Also from my personal experience with the boattails, I owned a 73 Riviera GS.

Also can mention here that in cars like the Centurion there was an HO (high output option? (Brad, Adam can correct me here or add to this) This option was designated in the VIN and did have the larger stage 1 valves. I have heard this is the same case with the '69-'70 Riv's, but there is nothing noting it in the VIN.

 

According to the ROA, it is a hit-or-miss deal about whether or not a GS Riv will have large valve heads. Some did, some didn't.

I have spoken to a lot of people that have torn apart original 70, 71 and 72 GS Rivs. There is no rhyme or reason as to which cars will have the big valves. And nobody has been able to find out what criteria Buick used for installing them on an engine or not.

So, if you find a 70, 71 or 72 Riv GS, there is NO GUARANTEE that it will have the big valve heads.

 

I will agree Yards!

 

ou: Yeah what do I know.... I guess there is no need to post the documentation

 

I stand corrected, Ric. I was confusing it with big valve motors in the NON-GS cars. Some 70 - 72 non-GS Rivs came with big valve heads, and those are the ones that there is no rhyme or reason for it.