i have spent a week and a half ordering motor mounts to put in a 400 into the bronco and cant seem to find the right ones. the ones off of the 351m wont bolt up to the engine and the ones for the 400 wont mount to the truck? thanks for any help you can give me. tried to do a search and found nothing

 

The 351M and the 400 use the same block. I'm a little confused as to how what you're describing could be possible.

 

yea, i don't get it. those should work. try a set from Broncograveyard.com i have a set on my 77 f150 with a 400. work great. good price.

 

thats what everybody says "same block" . the 351m mount only has one hole that will line up and the other two holes sets to one side or the other. I'M LOST? anybody tell me "how to tell if this is a 400" other than the valve cover sticker?

 

There's a casting code on the lower right side block near the starter motor. It should start with a 'D' followed by a number and then more letters. Post the code here and we'll see if we can help.

 

It doesn't matter, they are the same block, they have the same parts, they have the same everything except for the crankshaft and pistons. you have different alignment holes, you are just going ot have to find some out of a junkyard or something, have you made any changes to the frame or has it been in a wreck, thats the only way that they would not fit.

 

As others have noted, the blocks are identical, so the engine mounts for either 351M or 400 will fit any 351M or 400 block.

The right and left side engine mounts are not interchangeable on M-block (351M/400) engines. I suspect you got the sides reversed.

 

thats what i was thinking might be your prob. check which side they go on.

 

yep checked that to clearly marked "L" and "R" even tried swaping sides to see if they were marked wrong

 

has to be our wounderful parts stores. the motor mounts off the old 351m bolt up prefect. should have tried them in the first place, just i'd put new ones on while the engine was out.