Mopar Action On-line – Tech Questions
Paul Wooten, Spring, TX, 1968 Dodge Coronet 318
I have a 1972 400 HP. What is the maximum bore I can gowith. The block has been bored .040 over and needs to be re-bored (probably.060). Can this be done and if so, where can I get pistons to fit? All I canfind is .040 over pistons. Any help would be greately apreciated.
As you probably know already, the factory called for no more than0.040″ O/S. And, the more you bore, the more you weaken the cylinder walls.But some of these blocks had amazingly thick cylinder walls, so I’d saysonic test ’em – a very quick and inexpensive process. Look for at least0.100″ on the major thrust side. More is better!
Failing that, 400 blocks are pretty easy to find.
Assuming the 0.060″ bore job, any of the California piston houses – JE,Probe, CP, Arias, etc. will happily make you whatever bore and squeeze youdesire – with lots less weight, and more strength, to boot.