- Buick Ownership
- 1968 Buick Skylark
What made a 1968 350 cu. in. engine a 230 hp or a 280 hp engine? Were they made differently besides having different carburetors?
I see these questions all the time. Someone wants to know how much horse power they have, sometimes after they added x, y, and z to the engine. Prior to the early 70's, engines were rated in a different way than they are today.What made a 1968 350 cu. in. engine a 230 hp or a 280 hp engine? Were they made differently besides having different carburetors?
Smaller combustion chambers, and smaller piston dish/valve reliefs. Also, stock pistons tops are actually down in the hole .040" to as much as .090" at TDC. When rebuilding an engine, it pays to strive for zero deck. Zero deck is when the piston top is even with the block deck at TDC. More efficiency and power and resistance to detonation are the result. Here's a static compression calculation for my engine,What makes the compression higher?
No, cylinder heads were the same. Piston dish volume was different. One engine was rated at 9:1 compression, and the other was 10.25:1. I can tell you even that was fudged. When taken apart and measured, the compression was less.So basically in 1968 they made a 350 engine with 2 different cylinder heads and pistons correct?