I think price wise it'd be similar. performance not sure, but also could be pretty comparable......could come down what parts do you have right now. meaning if you've got a 62t cylinder or 64x cylinder. and T cases go with CPT. I got my pArts super cheap so he's doing my 780 and T case porting and will run it as He sets it up since his system is proven. but I've got a very strong 61x/61x motor that's my "go to" motor that just keeps running. I'm thinking of dropping in the 4 mill as a test. in that one since it runs so well currently I could do a clear before and after comparison. not sure if this helps or not but I'm almost literally in the same spot as you are.