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Hey, I have never heard of these engines before. What did vehicles they come in?

They were specifically designed engines for medium and heavy duty trucks as well as industrial and marine applications. As far as trucks they were optional in the 700/750 series and up.

Thanks, good to know that this section is here

These would be engines with the standardized bell pattern much like the diesels, such as IH, Cummins, Kenworth, Mack, etc?

Or did they have a BBF "460" bell pattern as in the toy trucks, like the F350 series?

Check the other postings here. Scroll down on this one:

https://www.ford-trucks.com/forums/s...d.php?t=217996

He says they have an SAE pattern bell.

These are what the word "obsolete" was invented for.

Does anyone make an adaptor for these motors to mate them to a modern tranny? or will one have to be custom?

The SAE bellhousing pattern means lots of trannies will fit.

By modern trans, what are you thinking of?

Im thinking of a mustang manual 5 speed, or just about any other modern manual tranny

Mustang manual 5 speeds are usually T5's, rated about 300 to 350 lb-ft of torque.

Depending on what vehicle you have in mind, they will last a matter of hours, minutes, or possibly seconds behind a 534.

Thinking of putting one of these pigs in a small car to make a hotrod?

The tremec 5 speed in Jegs will hold 600lb-ft of torque. Or maybe I could use the richmond 5 or 6 speed manuals?