So, I have a friend that has totally stock 500EFIs with just a tick over 500hrs on them, they have never been opened up and I do not think they have ever had valve springs done. They run great, so the question is do they need immediate rebuild or can he get by on doing valve springs, keepers/retainers and possibly rockers? Are head gaskets an issue?

Compression did looks decent, have yet to do a leakdown.

I think the 525's & 525 sc's had head gasket issues from what I've read, along with springs and rockers I'd replace the lifters also...jmo

if the bottom end is tight on the leak down,,replace springs and run it.not using any great amount of oil or blowing blue smoke on start up?if not,springs and go.

I just talked to him, he wants to pull the motors, it is the end of the season and he/we will have all winter to rebuild/refresh.

So, with 500hrs are the rockers automatically past their usable life? How about the cams? If they look good run them? Would there be any advantage to upgrading to a 525 (741) cams?

If all valves open the same amount, cams are ok. If he is gonna pull them, he most likely won't be able to not upgrade cams. Whatcha got for exhausts? The ones Lok like Gils or the ones look like CMI E-tops? If Gils, need new manifolds. If header style, need leak tested. They are iron GM rectangle heads. So 4 new heads is 4k more spent. You pull engines, you will pull the pans. Check rod bearings. Push pistons out to replace the rings. Next thing, rebore and new pistons long as going that
​​ far, may as well add 1/4 inch stroke and have 540's. Now these valve springs cost you 15K...

They are Etops, all fresh water use, pressure check for sure but not real concerned about them. Also being fresh water the heads are most likely OK, they obviously will be inspected and gone through. He is on a budget so it will get what it needs and if an upgrade doesnt cost much more than a replacement part it will get it. I know how this **** snowballs but 15k is not in his budget.

I was just writing up worst case scenario to help him keep his wallet where it belongs...

How old are the e-tops? It's not so much corrosion as it is thermal cycling and vibration on the welds. Water collector is the weak point. Anything more than 10-12 years and your on borrowed time.

Having just gone thru this 4 times over...pull the heads and do everything right the first time.

-gaskets (fel pro)
-lifters (Johnson)
-rockers (scorpion or crane)
-push rods (trend or manton)
-springs (isky - take your pick)

Have the heads thoroughly inspected. Especially the valve guides for rot. Have builder inspect valves and replace as necessary. Valve job. And put it all back together. Don't skimp on new parts. Sadly that's the cheap part. piece of mind goes a long way. At least in my book.

I can help you, PM me for details

I built a 500efi for a guy a few years ago, prob had a hard life, crane gold rockers had a few flat spots in rollers, lifters were marginal. Id replace all of it at 500 hrs fwiw. I had a 500 carbed apart w 500 hrs, lifters had pins falling out of them, rockers were junk, head gaskets were falling apart, fwiw, smitty