All good information is helpful Jeff....
....even if it's not what you thought at first, it could keep you away from a dead end. Nice looking boat, & good job of refinishing. Looks like a little too much fin though unless it's a long straight with tight turns.
Turned out I gave some bad information myself. I had thought I did a kilo record and a competition record with 41994 in the same year. That was my goal, but it didn't happen. The competition record I set in 1976 was also with a Marshall Grant motor, but it was the double rotary valve "F". I have to spend a little time getting all of this straight because I lost some notes and my files are all scattered.
Marshall didn't keep notes on serial numbers and I don't think many people do. I did through part of my racing career and quit toward the end, but I would never remember a number in the wee hours of the morning from any other motor we had unless it was the "Donald Duck" motor. The fact that the number was so unusual and that we spent more than six weeks trying to figure out how to correct this perplexing high speed miss must have ingrained that number in my brain from writing up so many test sheets.
Just a thought............
I know you said you were going to display this engine, but just in case you get the urge to hear that sound and smell the castor..............
Does it have retainers w/loose needles on the wrist pin end or caged needles?
If option #1, change the retainers and spacers!! (If not all the bearings top to bottom.) The only tough one to get might be the split center one, but I'm sure there are still some around.
I can appreciate your thinking Jeff....
....but this ol' girl has come home to rest on a red wall. If I cranked her up and tore out a chunk, I would have lost some of the magic.
It's not the old style crank, and short of tearing it down where I can get a peak at the pistons from the backside, I'm saying they are the caged needle bearings. As I turned the motor there were no slight tight spots, stickiness or anything that felt like the bearings were bad or gummed up.
However, the bearings for the rotary valve belt are another story. They look like the same ones I last laid eyes on. They need to be injected with that purple stuff people take to loosen up their joints. But I am glad to have them as all they need to do now is provide tension for a replacement belt. I will have to find one of those. The one that came with the motor would only come down halfway down the top carb. BTW, what plugs do people use now. Are AC M40ffg's still around? I have no plugs either.
So I guess the plan is to get an incense pot. Fill it with a 20:1 methanol/castor oil mix. Light it off. Pop a top. And sit back listening to the Marshall Tucker Band while looking at the motor.:D