643 industrial head specs?

[puddlejumper]

Anybody out there have any information on 643 industrial heads. They came off a truck motor. I would like to use them on a mild 3x build, approximately 350 horsepower. They have the smoke combustion chamber like a 333, but the question is how well do they breathe, or should I move on to a pair of 817's.
Thanks!

 

[oldskydog]

That is an older struck head with combustion chamber and rotaters. The runners should be the same as the 379 heads. 333's or 817's should be better.

 

[Don Jacks]

The head you have might get you to your 350 horse mark with some work and bigger valves.817's will easily exceed that with just a good valve job and new valves.

 

[puddlejumper]

Thanks guys. Problem solved. A pair of 817's it is. Appreciate it!