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Apr 26th, 2026 | | AD Chevy Trucks  Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
Lots of work on Brad's part ... pure enjoyment (and references) for you!
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For helping keep this great
old truck web site
on the Internet for over 30 years! and not clogged down
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| | | | Joined: Oct 2007 Posts: 725 Shop Shark | | Shop Shark Joined: Oct 2007 Posts: 725 | Your casting number tells you nearly nothing. It was used for 1968-1979 327s and 350s, both 2 and 4 bolt! Factory HP ranges from 145 to 375. That number was also used as a "Hi-Perf" truck engine.
The only way to tell for sure is the stamped number in front of the left (drivers side) head. With HP ratings all over the board, you need to get the specifics on that engine and see how the HP was rated when it was built. Manufacturers played all kinds of number games to fit their production into Government regulations!
3970010 was also used by GM of Canada. Those engines could be found in some Buicks and Pontiacs. The Canadian engines were often rated higher in HP than identical USA engines.
"10" as final digits means nothing concerning the number or angle of bolts in the main caps.
Get that stamped number off the block for the real story!
I wouldn't do anything to the engine until it had a full tune-up and oil change. Adding an HEI and making sure the exhaust system was open wouldn't hurt either. Then you'll know what you have and can make informed decisions about what to change.
best wishes,
Les | | |
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