As posted earlier... 57 GMC pickups used a 347 cubic inch Pontiac Motor with a 2BBL intake.
The '57 and '58 pontiac and gmc V8 intakes are interchangeable as are the '57 and '58 crankshafts. The '59 gmc '336 motor is based off the '59 pontiac 389. The '59 336 intake is not interchangeable with the '58 336 V8 or the '58 pontiac 370. The stroke changed in the motors between '58 and '59. As the stroke was increased, so was the deck height of the block. Although the heads are interchangeable the intakes aren't as the '59 intakes will be wider than the '57-'58 intakes.
All the Pontiac based GMC V8s from 55-59 are considered "Big Blocks".
John
Thanks, John, the problem is that I am trying to be as accurate as possible. When you find conflicting information it is best to ask and do more research. The only information I have found on the web is in conflict with each other. I tend to accept the information that you have provided because it agrees with the other information from those who have taken the time to answer. It also confirms the list that ol red provided. I don't have the shop manuals for these years and only two of the many oldgmctruck guys that lurk here have bothered to assist in correcting this issue. I do appreciate your help and the other's who have assisted me. This will be available in the search engine for future reference, so accuracy is of the utmost concern. I plan on cleaning up the post when everything is confirmed, leaving the sources for the information intact so other's will understand where this information came from. Thanks again.
