Quote:
Originally Posted by bracker8040
I expect he would. He’s the guy building the pistons after all, and he wouldn’t do it if he didn’t think it was a good idea. 
I’m not disputing the fact that they are less likely to crack. But, a mismatched cone angle/bowl design is a bad idea. For example, look at the issues the Cummins guys have when they use 6.7 pistons and the wrong year 5.9 nozzle above it. More smoke, more heat, less power, etc. |
That's a bigger downside than what we're talking here though. The "narrow" part of the bowl isn't any smaller than factory. If you want to make power and have the pistons last, oval bowl is the only option besides a forged piston. Yes the Mahle race cast are just fine (which is what Jon machines his from) but for the ultimate cast setup you'll need oval bowls.
A delipped
LB7 piston might last for a while if not ragged on constantly, but an upgrade would be recommend by almost all builders, and if you're dropping money on the race cast parts, might as well go oval bowls.