[b-man]

3” headers?

Is that the collector size because it sure can’t be the primary pipe size.

All Pontiac blocks are dimensionally the same externally, the same physical size. If both have D-port heads (used on 99.99999% of Pontiac engines) which is highly likely then yes of course. Pontiac heads can be interchanged onto any Pontiac block.

And please let’s not bring up the short-deck 301 and 265 blocks that 99.99999999% of us don’t want or use.

[Badgoat64]

Originally Posted by b-man

3” headers?

Is that the collector size because it sure can’t be the primary pipe size.

All Pontiac blocks are dimensionally the same. If both have D-port heads which is highly likely then yes of course. Pontiac heads can be interchanged onto any Pontiac block.

And please let’s not bring up the short-deck 301 and 265 blocks that 99.99999999%’of us don’t want or use.

My 64 GTO has a 461 stroker (built from a 400 block) with Edelbrock heads. It is 3” exhaust from the headers to the tail pipes. Yes that’s the collector size. I’m just trying to figure out if I put the original 389 back in the car, will the headers on the 461 bolt up to the 389, or am I going to need to make exhaust mods.

This is my first Pontiac, so please forgive my lack of knowledge on the subject. Thanks.