Bartamos,
Your response is contradicted by the following. I still don't have a good answer to my question.
The GMC/Pontiac V-8. (by Bill Hanlon) From 1955 through 1959 small (less than 2 ton) GMC trucks with gasoline V8s were equipped with Pontiac V8s. In 55, 56 and 57 they were almost identical (bigger dishes in pistons for even lower compression ratios and Bendix/Stromberg carbs) to same year Pontiacs. In 58 they used the same block as Pontiac, but only bored it to 3.875" giving a 336.1 cubic inch engine instead of Pontiac's 370. In 59 they again used the same block as Pontiac, but only bored it to 3.78" giving 336.9 cubic inches instead of Pontiac's 389. Cranks, heads, rods, were the same as same year Pontiacs -- except the smaller bore GMC engines in 58/59 required different balancing, hence different cranks.
Wikipedia
336
GMC's own V8 was the 336-cubic-inch (5.5 L) OHV/pushrod engine. It used a 3.875 in (98.4 mm) bore and was produced only in 1958 and 1959.
While both the '58 and '59 GMC V8 engines were advertised as 336-cubic-inch (5.5 L), the '58 version was based on the Pontiac 370-cubic-inch (6.1 L), but with a smaller 3.875-inch bore giving 336.1 cubic inches (5,508 cc). The '59 version was based on Pontiac's 389-cubic-inch (6.4 L), but with a smaller 3.78-inch bore giving 336.9 cubic inches (5,521 cc).
Anyone else have any info?
