Thoughts on the 452 heads
I have a set of home ported 915s with 2.14-1.81 valves. Don't know what they flow, but lost e.t. when I bolted on stock pro comps. And their 40 lbs. lighter. It was alot of work. Once I ported the pro comps it was a different story.
So, your car slowed down when you installed ootb PC heads?
Which ones? The Victor copies?
I had a customer with a similar experience with some Indy SR’s about 20 years ago.
S/G roadster with pretty nicely ported 346’s with 2.18/1.81 valves.
One head developed a big crack under the middle two exhaust ports.
His brother, who also ran S/G had been down the cracked iron head road before and finally went to aluminum...... and never looked back.
Following that logic.......and it was right in the middle of the season with a national event coming up quick........ so rather than try and rush job another iron head, he bought some assembled, unported SR’s and ran them ootb.
It was slightly slower than it ran with the ported iron....... but the coolant stayed inside the motor.
He never looked back either.
Those SR’s are still in use.