Pontiac V8 engines are a distinct engine family — they are not interchangeable with Chevrolet, Buick, or Oldsmobile engines, despite sharing some vehicle platforms. Casting numbers help identify the specific engine.
WHERE TO FIND THE CASTING NUMBER: The block casting number on a Pontiac V8 is located on the front of the block on the passenger side. It is cast into the block and should be readable after cleaning.
COMMON PONTIAC V8 CASTING NUMBERS: 9790073: 389 ci — used in Pontiac GTO, Bonneville, and other models in the mid-1960s 9796465: 400 ci — one of the most common Pontiac V8s, used across GTO, Firebird, Trans Am, Bonneville, and others in the late 1960s and 1970s 9799266: 455 ci — Pontiac's largest displacement V8, used in high-performance and full-size applications in the early 1970s
IMPORTANT: PONTIAC IS NOT CHEVY: This is a critical point that causes confusion in swaps and parts ordering: • Pontiac engines have a different block design than Chevrolet engines • Head bolt pattern is different — Chevy heads do not fit on a Pontiac block • Accessory locations are different — Pontiac engines mount the water pump, alternator, and other accessories differently than Chevy • Bellhousing bolt pattern is the same as GM standard — Pontiac engines will work with GM automatics (TH350, TH400, 700R4, etc.) • If you're ordering a replacement Pontiac engine, make sure it is specifically a Pontiac engine — not a Chevy engine in a Pontiac vehicle
For help identifying your Pontiac engine and finding the right replacement, contact us at 1-844-XPARTS-1 or support@expediaparts.com.
