The 4.250 stroke 2.20 rod combo required no grinding in my RB block. I wouldn't bother with a 4.15 crank when you can get the 4.25 cranks for the same money and most likely not have any grinding to do. For the brand I have used 440 source, Molnar and Eagle and I have had no issues with any of them. Make sure you check them or have them checked by a machinist. I would buy who ever has the best price.