What his engine builder is referring to is that ARP does in fact recommend having the rods re-sized whereas Katech does not. When I say "re-sized" I mean having the rod openings checked for roundess with the bolts torqued down, not making the hole bigger for the bolts because that is fine as is. I put mine together with ARP's without re-sizing and won't lookg back on it. ARP just says this to cover all the bases. Many have done it with great success but if you want to be extra safe pay a few more $ and get the Katech bolts.

 

there are people on here that will tell you to have the rods resized and people who will say you don't have to. From what I've studied the ARP's are a tighter fit(larger) than the Ktechs and tend to swell the rod at the center of the cap, making the clearance tighter in the center of the rod. This "could" lead to a spun bearing if it tightens too much so I'd be sure and check it with some plastigage. Then again, the area they say will be tighter can't be checked that way since it's right beside the cap break. If I already had the motor down I'd have it done just to be safe anyway.