As Bjorn suggested, I would try to find out from the last owner what the specs were, and or who built the motor and contact them for further information.

Then you'll have a better idea of what direction to go, and or maybe a better idea of which heads will work better with your cam/intake and carb combo. But any of the heads Q mentioned would get you much closer to a match I would think than what you have at this point.

But your going about it right... asking the questions, learning, and then you can make an educated decision and know your spending your money wisely!

And it's nothing you have to do right now... you can work at it slowly. Find the heads... then in a few months have them built... a few more months tear it down and install them just in time for spring etc...

Brett - 67 Drop Top 455!