HELP: Engine swap!

I have a 1965 Mercury Comet caliente that I want to take the stock 289 out of and put a 351 Cleveland from a '70 mustang. I also want to put a set of long-tube headers on the Cleveland first, but I dont' know if the engine will even fit, period. Anyone have any suggestions?

Hi Jake,
I don't think your 65 Caliente is much different dimensionally than my 67 Ranchero...
I have a 351 Cleveland 4V from a 70 Torino with a C-4 auto / column shift in it.
I think you should have no problems fitting the engine in, although it's going to be tight compared to the 289.
My best guess is that the long tube headers are not going to be a workable option without MAJOR modification.
I'm using the stock Cleveland 4V exhaust manifolds which fit nicely. ( Install the manifolds before you put the engine in) With a cross over, FlowMasters, and dual pipes out the back, it sounds and performs very well!