Khyren

The M's were put in trucks up until I think 84.

dirtcrew51m

The m were also in cars. They were replacements for clevelands, started in 74, they had taller block, more stroke, same heads, they were made for torque, but they were slugs, thats why they did not last, also the emission police caught up with them, also a reason cleveland heads are not used anymore. The ideal power motor is a 351w bottom and 351c heads. Most of the real hi po heads on race engines nowadays are cleveland based. The only good thing about m motors is we can steal the trans and use em on our big blocks.

__________________
"A Ford is a truck. Everything else is just a glorified tonka toy"
"92 F150 Supercab longbed - a rarity amongst supercabs-, 4x4, 302, unfortunately only an auto,
"If ya cant put a big block in it, its not wort having"
83 Mustang Convertible, 429 RHO (really hi output), C6, 9",

Khyren

In retrospect, I kinda wish I hadn't sold all of my cleveland stuff I had the good 4v heads with the closed chambers and all the rest of the parts to make for a 550hp screamer. Oh well, stuff happens. If you ever get a chance to, look at the intake ports of one of the 4v heads... They measure 2.5" x 1.75" and have about a 3/8" radius in the corners with 2.19 intake valves stock.