looking for a good used running 455 to put in my 72 skylark 350 car. called a friend who says his fathers old 1975 Riv has a stage 1 in it. did they have a stage 1 in 75? what year motor would be the best for me to find and buy. Thanks Kevo :3gears:
a 75 stage 1 riv should have a VIN that looks like 4Y87W5?9xxxxx 4 = Buick Y = Riviera 87 = 2 dr sports coupe W = Stg 1 Riviera 455 5 = year of manufacture or 1975 ? = letter designation for plant of manufacture 9xxxxx = production serial number buicks.net doesn't list a 75 stg 1 but i suppose the engine could be a holdover from 74. if so the block should be coded ZS. 75 and 76 had the highest quality blocks and 5/8" oil pickup ... but because of emissions they are also the lowest power engines. this is a combination of open combustion chamber and deeper piston dish. you can deck the block, heads and intakes but you'd have probably have to replace the pistons to get back to 10 or 10.5:1 compression anyways. the 1970 had by far the best power ... but good luck finding a normal 1970 455, much less a stg 1. it also had the smaller 1/2" oil pickup. to sum up, that 75 block would make a great base for a rebuild project (depending on preservation of course) but it would take a little money to get it to/past 1970 power specs.
I've got a 76 block with 71 heads on my Riv. I've often wondered how much power I'm really making/losing vs. a true 71. But I've never had any complaints about it.
Trevor, You shouldn't really be losing anything compared to a 71 block. The low compression drop in 75-6 was due to the open chamber heads, not the pistons. If you're using the 76 cam, that could be different than the 71 cam for emissions reasons (don't know).
Hey Trevor.I use a `75 block myself. As long as the pistons/rings are decent and your interested in pump freindly performance I would just keep the short block.Get some older heads,intake,800 carb,torque cam,headers and you should have a decent street car.Later,Tony.
