[chiphead]

Let's deal in real numbers here. I ran the compression through diamondracing's compression calculator.

Assume 95CC chambers: pistons .015" below deck, 6CC valve relief on a 30 over 455.

95CC Iron Heads: 9.26 compression
87CC heads: 9.88
72CC heads: 11.33

Theoretical 80CC head: 10.5 compression

11.33 compression is too high for a pump gas motor overseen by a non-expert. I wouldn't recommend over 10.25-10.5 with aluminum, just to keep some safety margin.

Over 10.75, the tuning window gets pretty small. One jetting mistake, timing mistake, bad fuel from an iffy gas station, overheat event and it'll blow a head gasket or worse. Lets not forget this is a stock rod motor with 4.21 stroke. It's already hard on the connecting rods. It'll be fun, until it goes BANG.

Maximum engine lifespan would dictate keeping the RPMs below 5500 and the engine out of detonation. Both of those are going to be hard north of 11:1 compression. Anything larger than a RAIV copy with high compression and good airflow is going to want to revv over 5500 in a 455, and we don't want that with stock rods.

I could rant on, but let's keep it simple. There are 3 realistic options as I see them: Each add complexity and cost.

1: The cheapest option is going to be super tuning the existing combination (Rhodes, adv cam 4*, etc) This may be enough, as the combo is respectable on paper.

2: Change the camshaft to 1 step smaller and super tune. I'd expect a massive improvement in street manners.

3: Swap the top end to increase the compression, headers, 3" exhaust, upgraded fuel system, etc. 10:1 with irons or 10.5 with aluminum is what I'm thinking. Have to bring the A game with tuning.