No idea. I left it up to the engine builders discretion. He's been doing it for 30+ years. One of the best in the area. Bill Carlquist out of Watertown. I trust his judgement.

Hindsight should have just did them both but first motor is already back together as they were being done serially.

^^^^^^ok,i get it.i won,t tell you the story about the two salt water hp 500s that went through a shop i was employed at years back.i hope everything works out for you.

Thanks.

Why did you take the motors somewhere else justin?

They are will Carlquist Competition. Fixed my post. My bad.

I hope you didn't spend good money to make new parts , like old parts , for commonality ? Especially when your old parts , were going to
need to be new parts soon? I would never do that , to , or , for , a Customer , just not logical .

Not sure why anyone these days, would want to fuk around rebuilding some old iron salt castings. Engine Quest makes a 502 Replacement head, that has 3/8' guides, the heat crossover port, etc. The head is designed to replace the GM/MERC iron head. You transfer over your valves and hardware. These castings are around 400 dollars each shipped to you.

Whats a machine shop charge to replace guides in a GM/MERC head? How about valve seats? Do they sonic check the head to find thin spots? Magnufluxing? Milling? By the time you get done with all that, you still have a 15,20,30 year old casting that cost you nearly the same money to simply just buy a new casting.

I really don't see a problem reusing old valves, as long as they check out, and there is enough margin left. If they are compromised, and new valves are needed, I would move right on to the engine quest 320 heads, that take a 11/32 valve, and is a much better performing head then the above. Or, a different performance aftermarket head if desired, dart, afr, brodix, whatever.

I've seen friends waste thousands of dollars rebuilding those old iron merc castings, dealing with rot, seat cracking, and all kinds of issues. They just aren't worth sinking money into, IMO. Now, if they are a clean freshwater set, and at rebuild time, just need a valve job, thats a different story.

Just my opinion on the topic.

Exactly.

You are coming late to the party. To save you some reading, these motors have been gone thru 2-3 times already in the last 2 years. The entire valve train is new including lifters, springs, push rods, valve seals, valve guides, valves, rockers, head bolts, gaskets, and now heads.

Trying to save myself from re-spending money on valve train components that are brand new.

In hindsight I agree. But like I mentioned it wasn't the original plan to swap heads as the ones on the first engine appear to be in good shape with the exception of the valve guides. Interestingly enough he said valve guides look to be in better shape on second engine but head looks worse. Who knows.

The fact that a mechine shop went thru these last year and didn't recommend changing them tells me they aren't bad and likely is a pre cautionary move this time around. Don't want to blow this stuff out of proportion. They aren't rotting off the motor.