The 340 is notorious as a "dirty" engine. I believe that its two-year production run was due to the start of Federal emissions standards in 1968. The 350 was designed for cleaner performance.
Pat, listen to Louis he knows what he is talking about, the pistons are most likely dished, not very prone to detonation in my experience. those pistons with a composition head gasket would give about 9.75 to one. a big improvement in h power. Doc
IMHO, It would ping like crazy on pump gas. Our local custom engine rebuilder told me that he would not guarantee a rebuild of my engine if I used the original-type pistons due to the high compression. Showed me a trade association newsletter stating that consensus. Luckily, mine doesn't need a rebuild.
A nailhead is a Buick V-8 engine design used between about 1954 and 1966. It is distinctive by the vertical orientation of the valve covers. The valves are small and nail-shaped.
WHAT ABOUT THE 300's? I believe the GSCA classifies the Buick 300 as a nailhead, I believe because of the thickwall block configuration, but carries the "modern" Buick engine starter, timing chain cover, and firing order. Maybe not a true nailhead, just an updated, downsized version. Anyone agree, disagree?
The Buick 300 is NOT a nailhead! I've never heard any reference to the 215/300/340 series as being "nailheads" other than a mention of a 340 as a "mini-nailhead" in the August 2000 edition of Hot Rod. And, that statement was by a writer who admitted being unfamilar with that engine series.
