[whirlwind]

i never had a regular 400,but im talking bout the 400"M". it was a piece of crap.in my opinion any way. i had one in my 79 bronco.that was the legging-est thing i ever had in my life. and it over heated often. the mechanic i took it too said the over heating was common with the 400"M" because the 351's engine walls (or whatever?) werent thick enough and when they bored the cylinder's out the heat transfered faster ...idunno,my head started spinning like linda blair in the exorsist after his first few words...i could be mistaken on a few points but that was the main jist of what he said

[G Hollingsworth]

The change was about 87-88 when ford changed to a aluminun 5 speed. The change date is not important except the fact they went form good to bad.Had two types and I have overhauled a number of them. The nice part is,in the heavy duty type,and if you use you head you don't have to take the trans out of the truck.Everything comes out the back. By the way New Process is made by Mopar and was used from about 78 on till they changed to the 5 speed