I'm currently assembling a new-to-me 460 engine from a rolled truck that I purchased with 10k miles on a fresh rebuild to replace the worn out unit in my '78 F250.

My old engine is a D1VE-6105-A2B block. Right after that number is an "81" marking, oriented 90° to the serial number if I remember correctly (I'm not near the engine at the moment).

This engine ran smooth as butter with a counterweighted "hatchet" front sleeve, which goes against everything I have read about the D1VE engines. The flex plate has no balance weight on it. I cannot claim to know much about this engine's history, so who knows what crankshaft is in it. I know that a balanced crank will be a 2Y variant, but the engine is resting on the oil pan at the moment. I can always lift it and pull the pan to look more closely.

My "new" engine is a D9TE-AB block, and it came with a plain front sleeve with no counterweight. Once again this seems to go against everything I've read about these blocks being externally balanced. I have not installed the pan yet, and a first glance at the crankshaft reveals nothing as far as 2Y or 3Y markings. I'll be working on it later today so I can rotate the engine to get a closer look. It would be great to know where to look for these numbers, or what other clues I should look out for. I can say that there are some drill marks on the ends of the two or three counterweights that are currently visible, as if it's been balanced.

Also a while back I purchased this new flex plate from Rock Auto. It was listed as correct for a '78 460, but it has a counterweight, which from everything I have read was not used until mid-'79. If need be I'll return it for non weighted one such as this one.

So long story short, I seem to have quite a hodgepodge of parts here, and two engines with unknown histories. Once I've figured out what crank is in the new engine I will have some decisions to make as far as which front sleeve and flex plate to use. Any advice will be greatly appreciated.

 

Really the block casting number doesn't directly indicate if the assembly is internally or externally balanced. Any block could be used with the external balance style crank, they will fit in any block and work. The D9TE crankcase is machined slightly differently than the early blocks but it doesn't take much grinding to make the early crank fit in one of those either. A mix and match setup would be possible if the assembly was custom balanced. I always hate when people do stuff like that but it gets done all the time. When Scat first came out with their cast iron stroker cranks in 4.300 and 4.500 stroke the 4.500 was cut to use a 6.635 minimum rod length and this made it take about 6 slugs of heavy metal to internally balance. But if you used the crank with the external hatchet and weighted flexplate it was pretty easy to balance. The difference is about 450 grams or so at each end.

 

Thanks Dave, and yes I get that mutt motors get built all the time. What really has me confused is how smooth my old engine was with a mismatched front sleeve and flex plate setup. As I mentioned I really need to find out what combination the new crank I'm using would run the smoothest with, and I really don't want to have to swap out the flex plate later, obviously!

 

I'm not sure how it wouldn't vibrate with that combination of parts because the wrong combination of parts will be WAY out of balance. If the engine has the older style crank and it is running smooth with the hatchet weighted spacer then there will have to be several large non factory holes drilled into the front counterweight directly in line with the weight.

 

Tomorrow I will double check the flex plate on the old engine to make sure it has no counterweight. If it doesn't have one then I'm as stumped as you are as to why the engine was so smooth. I will also do my best to ID the crank in the new engine.

By the way, I have some background with this issue that goes back to my youth. In 1979 at 18 YO I rescued a 1970 Mustang that had an engine fire that turned out to have actually been caused by a burst ATF coolant line.

I hired a local mechanic who was best known for installing transmissions without a transmission jack to convert the car to a 4 speed stick setup. He would just rest the tranny on his chest, roll under the jacked up car on a creeper, and horse it into place. Being 19 that was impressive enough for me, plus he was a couple blocks from my house.

Turns out that while he was strong of body, not so much of mind. That car shook like a jackhammer until I finally pulled the flywheel myself and had it balanced (or counterweighted, I can't recall which). It was smooth as butter after that, and then I promptly sold it. Dumb@$$.

 

I had a guy one time who brought in a flywheel to grind. I got it done and later when he called I told him that I had his 300 6 cylinder flywheel done, ready to go.... He said, "I don't have a 300, I have a 351". I told him that if he has a 351 then he has the wrong flywheel. Later he got the right flywheel for the engine and it ran much smoother.