Hey guys what are your thoughts, If I change the rod bolts from stock to ARP is it always to necessary have the rods re-sized.Theres really nothing wrong with the stock ones,more of a pm.The rods are from gen 6 502.

Pretty much the standard to.

I have trouble understanding why though since the bolt is used to align the cap and rod. As long as the bolt dia's are the exact same, should still be dead nuts, otherwise you shouldn't be able to even remove the cap. No different than the dies I built where the die blocks and punch holders locations are held to .0001 or so with dowel pins. Gotta tear them aprt for regrinds and repair.
I'd like to hear the engine builders reasoning on this.

How did your old bearings looks after the tear down? It's always a good safety measure to have it done. At the very least torque your new bolts down to spec and mic them w/o the bearings. Any performance engine I rebuild it's always an automatic. Just one of those things however I don't know how hard you run your engines. If it was for my plow truck I wouldn't bother but then again I would be putting ARPs for rod bolts in either.

I bought these engines from another OSO member,and they were already apart so i didnt see the old bearings.I do know they were running take outs ,but the gentleman said he felt they were losing power and thats the reason he pulled them.But if its a standard process for performance engines I will definently get it done,not looking to cut any corners.

I know it sucks trust me when it comes to the money that goes into these engines. Your doing the right thing by having them done. Especially if the engine or engines were getting tired. In a nutshell other internal parts start to transform. It's a step you'll take that will make you feel much better about your rebuilds. Even after you get them resized be sure and mic and or at the very least plastigage every rod. You may also let your machine shop know this is for a marine application. Personally I prefer a touch more clearance than that of the norm however still within tolerable means. Mainly due to the cooler oil temps in a marine application. I am not a prof. engine builder by any means however just what has worked for me over the last 20 yrs.