I need to rebuild my very tired 47 UTU engine. Right now It has about 40psi of compression on each cylinder. AND STILL RUNS!. I want to rebuild it, but don"t want to spend $900.I heard once before, you can use GMC truck pistons with minor alterations in a MM R. It has been a while since I heard that, but I thought you only had to bore out the wrist pin a little more. I figure very common GMC pistons probably are far cheaper than MM pistons. So is there any tricks like this for a U engine? I need to bore it out .020 to .040. Is there a common piston that would be available from Napa. If not, where can you get oversized pistons for a U. Also how much can you shave the head and or block. I would like to raise the compression to about 7.5:1 . Would there be a problem with that. On other U"s, I noticed that the piston only comes within about 1/4 inch of the top of the block. Could a person safely shave the block along with the head for higher compression? Thanks for any advice. I need to start working on that very tired engine sometime soon. BTW: It has been converted to 12 volts so starting with higher compression isn"t going to be that much a problem.
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