Hello everyone.

I just bought a 2005 525 efi engine with 285 hours.
Previous owner said he did some of the top end at 235 hours, but used stock parts i believe.
They changed the springs, intake valves and adjusted the rockers.
I didn't care to much about that, because i am doing it the proper way anyway.

I have manage to find most of the parts i need through this forum but i am struggling with the rockers.
There are so many to choose from and i am not sure which ones will fit with the other parts i'm ordering.

This is my list so far:
COMP Cams Valve Seals 515-16
COMP Cams Super Valve Locks 612-16
COMP Cams Steel Valve Spring Retainers 748-16
Isky Valve Springs 8005A

I was reading about these crower stainless steel ones and i would like to order them, but i'm not sure which one to choose from there website.
Is there anybody who have a part nr or can guide me a little?

Is this all that need to be done for a top end or does anybody else have some other recommendation?
Maybe change the lifters and push rods aswell?
Jan

What's wrong with the Crane rockers it came with? 285 hours does not seem like a lot of time at all. And the spring rate of the 8005A isn't crazy so unless there's a real problem, seems like you're trying to solve one that isn't there.

Check you hours - that ECM will tell you at what RPMs the engine spent a lot of its life. If it was babied, then I wouldn't even bother with any of it.

I cant post any pictures yet, but i can see that poly-lock is rubbing the body of the rocker. Some more than others, so i am changing them regardless.

Got it. You didn't mention the rubbing.

Crower 73605-16 is the standard Enduro rocker for the BBC (1.7 ratio, no offset). These will clear the 748 retainer (I'm using this setup on my AFR heads). You made need to measure for new pushrods.

Nothing wrong with the cranes. If replacing- COMP 1620
Always check geometry.

Ok thank you both
Since there are production delay at Crower, i ordered Comp Cams Ultra Pro Magnum XD Roller Rocker Arms 1820-16 and all of the other parts from Summit.

We went with scorpion rockers with our rebuilds. I think that’s what Mercury racing uses now..

Thanks