Forged 273 crank in an early 360 Block?
I fully understand "quench" effects on detonation & the fact that stock deck hieght will probably be more than published specs.
The .048 effective piston/head deck clearance I cited was what I thought to be a good compromise of adequate clearance, good quench distance & compression ratio. If the deck hieght of the block was sufficient (eccessive) after squaring, the head gasket thickness could be reduced to yield the the desired .048" clearance & 10.5:1 compression ratio.
As far as bigger valves reducing CR, of course it wouldn't. My thoughts on that were if the valves were unshrouded, thereby increasing combustion chamber volume & decreasing CR, why not take advantage of the unshroiuding by opening up the bowl & utilizing a larger valve.
EDIT: THe .048" quench distance/10.5:1 CR was computed for the de-troked 360 using KB 340 flat toped pistons @ + .012" .+ .060" head gasket.
A 360 utilizing KB flat top pistons @ zero deck & .039 head gasket would net 10.4:1 W 66cc chamber volume while the next step lower CR W/the KB piston (18cc head volume) would be 9.8:1 W/the stock 59cc chamber volume.
I am not new @ building/modifying engines. Most of my experience has been W/SB Chevies & Harley big twin strokers. I just purcahsed a "65" Valient for my son & I am trying to help him build a budget screamer.
He wants to make it faster than his Mom & Dad's highly modified Daytona Charger.
Well quicker maybe, @ 175 MPH, faster in that little Valiant would take a lot of $$$$$..
Locomotion said
I fully understand "quench" effects on detonation & the fact that stock deck hieght will probably be more than published specs.
The .048 effective piston/head deck clearance I cited was what I thought to be a good compromise of adequate clearance, good quench distance & compression ratio. If the deck hieght of the block was sufficient (eccessive) after squaring, the head gasket thickness could be reduced to yield the the desired .048" clearance & 10.5:1 compression ratio.
As far as bigger valves reducing CR, of course it wouldn't. My thoughts on that were if the valves were unshrouded, thereby increasing combustion chamber volume & decreasing CR, why not take advantage of the unshroiuding by opening up the bowl & utilizing a larger valve.
EDIT: THe .048" quench distance/10.5:1 CR was computed for the de-troked 360 using KB 340 flat toped pistons @ + .012" .+ .060" head gasket.
A 360 utilizing KB flat top pistons @ zero deck & .039 head gasket would net 10.4:1 W 66cc chamber volume while the next step lower CR W/the KB piston (18cc head volume) would be 9.8:1 W/the stock 59cc chamber volume.
I am not new @ building/modifying engines. Most of my experience has been W/SB Chevies & Harley big twin strokers. I just purcahsed a "65" Valient for my son & I am trying to help him build a budget screamer.
He wants to make it faster than his Mom & Dad's highly modified Daytona Charger.
Well quicker maybe, @ 175 MPH, faster in that little Valiant would take a lot of $$$$$..