Hello everybody. I just found this board after searching for about a month. I recently picked up a new toy for me to play with. It is a '76 GMC Sprint SP (basically can El Camino). The wonderful thing is that it has a 1970 BBB 455 and a TH400 tranny. The not so wonderful thing is it's got a 2.56 pegleg rear end. I was also told it was a Stage 1 engine. I tried checking the casting code in the block but the only thing I could read was "F". I couldn't see anything else before or after that (I did have to scrape off a lot of paint/grease to check this). I absolutely love to drive this thing. Even though it weighs 4100lbs with me in it, it's the fastest thing we have in our family ('00 monte carlo pace car 16.2@85mph, '76 Chev 1/2-ton 15.7@86mph). I made three runs using my Gtech Pro the other day and had a best of 14.94@98mph. This was with an extra rear end and spare rims/tires in the bed, and pretty much zero traction half way through first gear. I paid $1800 for this beauty. My goals are for a 12.99 or better 1/4 mile time, and still retain close to the current 14mpg I'm getting (this is my daily driver by the way). Pictures can be seen here: Click here for pics. The rear end has been replaced once already that I know of. The previous owner blew it up doing burnouts into drive (well over 100mph with 2.56 gears and 28" tall tires. I'm hoping I wont have any problems with the rear in it now, it is an 8.5" 10-bolt (so was the rear the previous owner blew up). Anyway, that's about all I've got to say for now. Let me know what ya think of my new toy, and some other ways to tell if I really do have a '70 Stage 1 455. Charles
Welcome to the board, Charles. Pretty cool car you have there! The Chevy guys must scratch their heads when you open the hood! What the heck kinda motor is that? I see you've got chrome valve covers. The Stage 1 came with them, while the non-stage did not. Although someone may have added them, at least it's an indication. The original carb is gone, so checking numbers on there won't help. The blcok casting number in your pic checks out to be a '70 or '71 engine according to this site. In case you didn't know, there is no difference in casting numbers for the heads for stage/non-stage, just bigger valves in the stage. I believe the "F" you saw would probably make it an "SF" code motor. If I'm not mistaken, I believe this would be a '70 Riviera motor. From what I've read on this site, there is a misconception that the Riviera motor was a stage 1 because the HP was rated higher than the non-stage 455 (and the A-body GS Stage motor). Popular opinion is the HP rating was an insurance game and that the heavier cars were given a higher rating without causing an insurance stir, but were actually the same small valve non-stage motor. If the distributor is original, the Stage 1 distributor number would be 1111962. Well, I've given you some clues, but not a definite answer. My guess, however, is that you have a non-stage motor with chrome valve covers added. I'm sure other more knowledgeable people will chime in. Welcome to the board and good luck!
Welcome aboard! I love hearing of Buick powered Chevy's! Kinda makes up for all the Buicks now suffering Chevy-power. I don't know if I'm more knowledgeable, but I'm gonna chime in anyway. :laugh: Yes, the big cars were rated higher and were still small valve heads. However, that doesn't mean this engine couldn't be a Stage 1. The Stage was available in Rivieras. The one in my Regal was donated by a Riv. Chrome varied from year to year; mine had the chrome air cleaner, but not the valve covers. I think its possible the engine is a true Stage 1. I don't know if the Rivs got the same distributor; probably. They did get a different cam than the A-body Stage 1's. It was designed to make a bit more low-end torque to help get the big car moving. Hopefully one of our Riviera brothers can provide more info.
Try cleaning the block number area with brake cleaner and then buffing with 0000 steel wool. Yo may be able to read the 2 letter code then. Also, the letters are often far forward of the production number. look all the way up to the heat oven. -In case you need it: 1970 Riv GS Stage Code SF SR SS Dist ?? ?? 1112016 Carb ?? ?? 7047047 Head casting all - 1231786 1971 Riv GS Stage Code TR TA TS Dist 1112016 Carb 7041540 7041242 Head casting all - 1237661 Also - the chrome rocker covers and oil cap were either Stage I or a dealer option called engine dress up kit. The block casting number you have was also used in the early 1971 production, prior to the enlarging of the oil passages. However the head casting number on the 71 is different from the 70. Last idea: and someone correct this if I'm wrong...I think the Stage I came with a higher capacity fuel pump which can be seen as a deeper diaphram housing.
Just to let you all know,in 1970,the distibutor number is 1112016 and the carburetor number is 7040246.These numbers are for Stage 1 equipped cars.
I love it- a Buick torquemonster motor in a chevy. Makes up for the 502 chev I saw last summer in a Roadmaster. I'm still waiting to find one in a mopar, that would really make my day.:laugh: :beer
