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I have 2- 351Ms I'm trying to decide on which one to start rebuilding. Both are MCC, 1 was from '78 that I know nothing about. And the other I can't read the date code on since it was rusted pretty bad. Anywhere else I can look? From my casting number starting with D7TE Here says it's a 77-82. The picture makes it look like a 9 but it's more ambiguous in person. It's definitely not a 7, so is there any reason to look further to make sure it's not in the bad dates for castings?
Looks to me like 6J4 which my thinking is "October 4, 1976".
J is the10th letter, 10th month is October.
I was not sure what the second picture was taken of.
Below is of my 400 from a '79 F-350 wrecker, casting code is December 20, 1978r, build date is January 4, 1979. I rewrote the build date as the 9 looked like a 7 when I wrote it first with my Sharpie, but it's a 9.
Got my numbers mixed up. This one is a MCC D1AE-6015-A2C. The build date on the front is 73K9W. So this was from a car from '73. This would put it in the bad date range since it's pre 77, correct?
My other block is a MCC D7TE with a cast date of 8 D10 (APR 78). So that one should be safe.
Time to start over tearing down this other block then. I did need the intake and crank though so not too much time wasted.
My '77 truck was built in March, 1977, but the 351M in it was cast Jan 7th, 1977 but I don't know it's build date. I've had the intake off years ago, but I do not recall if it has the older smooth inner lifter valley walls or the ripples of the later ones. My 400 has the rippled, later lifter valley walls that are not known to be crack prone. But then, on the other hand, my older 351M has not cracked either.
In short, I don't know the change date. Earlier smooth walls Later rippled walls
It is a bunch of good info, thoughts too. I read it, saved it years ago.
I was given my 400 as I had just returned from a trip with near no oil pressure in 1992, I replaced lower end bearings in the truck, but had no idea how long it would last, and a buddy was retiring his last 351M/400 powered wrecker and so he gave me his used non rebuilt spare to get it out of his shop. I had, and still occasionally have ... ideas of putting the 400 in, but that 351M still runs 60 psi hot at 2500 ... so as long as it does, I'll keep the 351M in it likely as not. 400 is cleaned up, new bearings, polished crank, new rings, new pistons and a box of gaskets and timing set and harmonic balancer sitting on top of the coverings as it sits on a roll around stand in the basement ... whispering "put me in coach" whenever I look at it.
March 1st, 1977 was the change date he said, means my 351M is the older smooth valley wall block.
It is a bunch of good info, thoughts too. I read it, saved it years ago.
