What is it, exactly, and how do I tell if my spare block has it? Pictures with explanations are worth 1000 words...... uzzled:
When you look at the front of the engine with timing cover and cam out there is a flat machined round surface around the cam bearing you want to see the cam hole right in the center of this machined surface any offcenter could mean core shift. I have heard when the cam rides high in this surface it means the crank is higher in the block which makes more compression solving the mystery why some stock engines run better than others{not a good option for a bore job cause it makes the high side of the cylinder wall thin. Lin
Im sorry I guess ive looked at to many chevys, I looked at a BBB block today and the whole face is machined I dont know how to tell on a buick sorry. Lin
Another place to look is at the lifter bores. They should be pretty even all the way around. In this photo, notice the bore gets thinner in the valley area.
Now look at this photo. Notice the bores are thicker on the valley side? These photos are on the same block. That means that the lifter bores and cam are over slightly to one side. You'll see the same thing in cylinder walls to. That's why it's a good idea to get 455 blocks sonic tested.
That's the nice thing about a Chevy or Pontiac, they put a little meat in their blocks. I never did understand why Buick got so cheesey with their blocks, like it would have mattered if the engine in a 4,000 lb. car weighed another 100 lbs., big deal.
Did you ever wonder why Buicks always handle much better than expected ? Why they handle better than the other mid size GM models like chevys that have a lighter chassis ? Maybe it's that 100lbs less swinging around out front between the control arms.
Dino, All of the big block A-body cars weigh about the same, and have identical frames and suspensions with the exception of slightly different spring, shock, and tire combinations which would account for any handling differences. Buick saved 100 lbs. with a light engine, but added the weight back with more trim, heavier bumpers and brackets, die cast parts, sound deadening, etc.
Dino, In any case, I would have a hard time believing Buick's intent for building such a light block had anything to do with handling issues.
