.....Sun is finally out this morning. I'm going out to pull a valve cover off of my motor to get the head number for sure. I will then see if there is a factory head with a smaller combustion chamber. At least that would be engineered. I'm trying for some improvement without the time and expense of pulling the motor out of that behemouth. Earlier inquiries showed that I would spend as much to pull and reinstall as I would replacing pistons.

I earlier posted that the stock compression was 7.8:1 but charts in my Chilton manual show it to be 8:1. My local engine shop thinks that I can get a point with about a 18 cc's reduction in combustion chamber size. 9:1 with a cam would probably give me the extra poop I'm hopping for with moderate effort and expense.

My local shop says that you can use smaller port TBI intake with larger port heads. you just can't go the other way around.

I will also talk to Edelbrock because they show a TBI intake for 454's up to 1990. That intake might should be an improvement and might match earlier larger port heads.