I have a 390 that has a lot of work done to it and completly rebuilt.
My question is i want to drop it in a 78 f150 4 wheel drive. c6 ,posi rear end.
will my 390 bolt right in to the transmission. the 78 has a 400 in it atleast that is what the seller told me. motor mounts im not worried about. the 390 came out of a 71 f100 with a manual transmission. the new truck (''78) has a automatic tranny. so my next question is what about the flywheel. any help would be great.

 

yes the 390 will bolt up to a c-6, and you should not have a problem with getting a flexplate. got to a autoparts store or look in jegs.
Mitch

 

that is music to my ears.

 

i know a c6 will hook up to a 390 but can i pull out the 400 and drop the 390 in its place.. will the c6 that is bolted up to the 400 hook up to my 390. not sure about the bolt pattern. i know there is a c6 for a bigblock and a small block.

 

the 351/400M's are BB bolt patterns for trannys. and i am not 100% sure if the motor mounts are the same. i would have to lean more twords yes....???? but im only 60 percent sure.
but the 390 will bolt right up to the C-6 that you have.
Mitch

 

Whoa! The FE and the 335 blocks have different bolt paterns.

 

are you sure??? i could have sworn they were the same?
Mitch

 

Yeah the 351m,400,429, and 460 have the same pattern and the FE has a different one.

http://en.wikipedia.org/wiki/List_of...using_patterns

 

i believe that the 390 is a big block also. the c6 only has one bolt pattern but in differ sizes small and big block. i had a c4 on the 390 i will be pulling the motor out of the 78 with 400 this weekend and i will let u know for sure if it bolts up.

 

the 390 is a BB bolt pattern so is the 351/400? im sorry for giving you false info. i could have sworn it would have bolted up.
sorry
Mitch

 

the 289/300/302/351w are one pattern, the 351m/400m/429/460 is another pattern and the FE's 352/360/390/427/428 has their own..

You'll have to change the Transmission, and the frame mounts, but dropping the 390 in is very doable. Just have to locate the tranny and frame mounts.