Mopar Action On-line – Tech Questions
jason zalewski, prince albert, SK, canada, 1978 dodge monaco 360
I was wondering if it is possible to offset grind a 360 crankdown to a 2 inch rod journal. If so can it be done on a cast crank as wellas a forged? My plan would be to use a 4 inch stroke crank,offset grind it.125 inch to achieve a 4.25 stroke, use a 6.3 inch rod,1.09 comp heightpiston,at .060 overbore will come to 440 cube small block..will this combowork?
In a word: No. You have some math problems, for starters: If you offsetgrind a 2.125″ journal to 2.00″ you’ve only increased the stroke by 0.0625″,theoretical maximum..
Then there’s the cyl. wall thickness problem. The factory recommends 0.040″max. O/S for a reason. Any extra HP you’d get from the small displacementincrease from, say, 0.020″ to 0.060″ bore diameter would be much more thanoffset by wall flex, which equals blowby.
Then there’s the piston question. Sounds like yours will be hockey pucks. Ifthe engine will be drag race only, you’d get by. For street durability,though, I’d rate this engine combo about a 3 on a 10 scale.
The cast crank needs all the iron it comes with!