Tried a search, probably didn't do it right, sorry if this has been covered a hundred times.
When swapping 351c heads to a 351m/400 you have to use spacers to make up the difference in deck height to use a 351c intake right?
But if you want to run 351c heads on a 351m/400 and use a 351m/400 intake manifold you don't need to use the plate right?

 

Correct. The heads are basically the same. The spacers are required because of the difference in the deck height between the 351c and the 351M/400.

 

If you plan on using 351C 2V heads ,they are the same asthose on the 351M/400. If you're using the 351C 4V heads,you need the spacers and valley pan cover .You can't use a 351M/400 intake with 4V heads because the ports are much larger on the 4V heads,if you go this route you must also use a Cleveland intake....FF59

 

That's what I thought, just wanted to make sure, thanks. Matt.

 

Theres a set of spacers on ebay right now for 200 bucks.