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thanks RBT.
I was going to call David to ask him a crap load of questions, or maybe you can answer them for me?
what is a NIC bore? is that like a nickle bore, vs chrome bore vs steel bore?
is that beneficial, i read a bit about not using a ceramic coated ring on nic bore engine, have no idea.
is my engine a nic bore engine?
also i have read a bit about wizard and pro marine 481, piston rings and a couple other that will work but required them cut. is this true?

nikasil coated cylinders you got it, you need to use rings for that bore, there not the same as steel sleeve rings ,, , if it was me and my motor and the bore was bad, i would look into swaping to steel sleeves, just because im cheap,, if its good leave it! re ring, check piston clearance, new bearings, re seal, letter ripp..

Never put steel sleeves in them, either all steel or all nic. Major heat differences.
It is a nic motor, nic is great, but short life span.
The rings are titanium nitrate coated.

can you swap to steel if you use the correct pistons and rings and set it up for steel? i didn't think the heat difference is major, but steel does get hotter,, more friction ,,but its more forgiving, and cheaper.. im no motor builder so RBT will know whats best.

heads off, measured the head with a syringe and some acetone ( thiner then water). it measures out to 38 CC.
here are some pictures, i only took one head off.
the bores seems perfect, ran my had around them and they are dead smooth, no sign of a nick or anything. the only thing i found was a lined discoloration on cyl 4, i assume it is indicative of a stuck ring where the blow by is getting past.? thoughts....

looks like there's a wee bit of carbon build up ,, ,,,

I have one of these motors and it works great on my procomp. I'm in the process of rebuilding mine due to the Nic coming off the tops of the boar. The block went to Ruck, I got the nitrate rings from Speed master(best price at the time) and during assembly I found loose pins in the pistons. Like RBT said can't get Mahal pistons so I sent them state side to have them top pined to match the nitrate rings. I still have to assemble but all looks good. John Marles is the name of the guy in the states that does the pistons ( marlesjohn@gmail.com) and he also sells the nitrate rings but I never asked the price. I think it is worth re-building these motors I had mine for 5 years (bought it used) so no idea of the hours on it, but it will be like a new power head when done.
FYI
Mercrazy

Hey RBT
What jets do you recomend? I here these motors came with different jets when new and should have been changed after break-in but most never got done. Any input would be great....Thanks

No clue on the jets, I have not owned a carb since 1995.
I don't agree with top pinning used pistons. I would be measuring the bores and the skirts of the pistons. That nic doesn't look great.... Nor should it be expected to.
These are fantastic motors, they are certainly worth rebuilding!, but do it right and the motor will last a long time. For some reason these last A LOT longer than the EFI version.

this engine is starting to seem like it might be alot of work, and more bother then Ii need for a lake boat.
wonder if there are any 2.5 steel bores out there.
a ring set for this engine looks around 400 bucks a set of rings? 2400!!? wow.

Just run the shit out of it till it helicopters a rod and makes your block as useful as a stringless tennis racket.

Disclaimer- I don't know shit about fuck.