[Baron Von Zeppelin]

Not a big issue , but something that can benefit you a little going forward when surrounded by other Pontiac-aholics .... the 13 Heads are open chamber - not closed chamber.
1967 was the last year PMD used closed chamber design on production heads.

Check your intake casting date.
Maybe get lucky and be 1969.

And carb number too.

[goat69SD]

Originally Posted by Baron Von Zeppelin

Not a big issue , but something that can benefit you a little going forward when surrounded by other Pontiac-aholics .... the 13 Heads are open chamber - not closed chamber.
1967 was the last year PMD used closed chamber design on production heads.

Check your intake casting date.
Maybe get lucky and be 1969.

And carb number too.

I looked at these heads before mounting them. They were closed chamber and the valves were (if memory serves) 2.0 something exhaust 1. 7 or 9 can't remember now. But seemed very large to me. I have the build date on heads and the intake.

[johnta1]

X is Kansas City, KS
Built B-series cars

Congrats on finding the info.

[goat69SD]

Originally Posted by johnta1

X is Kansas City, KS
Built B-series cars

Congrats on finding the info.

Couldn't have known anything with out all you Pro's telling me what it all means. One more question. What is Built B series cars? Like GP or what. I just hope it is a good engine for this car. Not grandma's go getter .

[b-man]

Originally Posted by goat69SD

Couldn't have known anything with out all you Pro's telling me what it all means. One more question. What is Built B series cars? Like GP or what. I just hope it is a good engine for this car. Not grandma's go getter .

Any of the 1974 and earlier 400 blocks and some later ones are all a fine foundation for a performance engine build, it’s the heads and camshaft that determine the performance.

Your #13 heads were used as a higher performance 400 head, all engines using them were factory rated at 350 hp. Automatic transmission GTOs and GPs all used these heads in 1970, you have an excellent foundation already sitting in your garage.