WHICH MAIN BEARINGS 107M or 4263M

[PaulRV6]

I am debating on which ones to use, the harder 107M or the std material 4263M both by Fed mogul. I hear that if I use the harder brg and have a failure I will probably tear up the crank, but since our crank journals are nitrided is this a concern?
Don't want to spend the extra money if not needed but if it is a benefit that no problem. Please let me know.

paul

 

[Intercooler]

Uh yea! If you tear up a soft bearing your crank will be fine I use 107M's. If you lose one it will still tear it up regardless.

 

[Nick Micale]

We had one crank get damaged with the 4263 bearings. They do NOT like detonation.

Paul, on your rods with the cracks, we would definately NOT use them and have only found one out of many with that problem.

 

[Intercooler]

Spend the bucks! Soft bearings do not hold up to detonation and pound-out like hard bearings.

 

[Steve Wood]

Spend the money and avoid detonation!