Quote:

Considering that Pontiac, Oldsmobile and Cadillac had OEM engines with 4.21, 4.25 and 4.31"strokes, respectively, there is no reason why a 4.25" stroke in a B or RB block would be any different.

Reliability depends on quality of parts, how it is assembled, and how it is used.

R.



Hmmm. This gets complex. I have no idea what the deck height (from crank C/L to head gasket surface) is on the engines quoted, but the shorter the deck, and / or the longer the stroke, the shorter the piston needs to be to fit. Once the skirt gets very short, esp. with short rods, there's lots of side thrust / loading which is not conducive to longevity or durability. I think that, for many of us, the engineered-in robustness of Mopars is part of the attraction.

Since B and RB engines have, generally, the same bottom end (of the block) patterns, I build lowbuck B strokers (RB crank) by boring the main saddles to RB size. This way the crank is OEM strength (as is the bottom end of the block).

Of course, lots of different combos can be assembled, and most work quite well, but the original question was regarding reliability...

Rick