How hard is swaping big block into a 67 mustang???

I have a 67 mustang that originally came with a 289. I am going to swap in a 390 that I got a sweet deal on that I couldn't pass up [hopefully to be swaped with a 427 later on]. How hard is this project going to be. My friends and I are pretty familiar with cars and there parts, and are not affraid to fabricate anything.

The 390 was an available option for 1967-68. I heard they were a bear to work on, they even had holes drilled into the floor pan to change the rear spark plugs. I guess the best way to put one in is see if you can find one with the 390 already in, and talk to that person, take measurements and take some digital pictures. Also a factory service manual for that year with that engine would be a good start.

I don't think it'd be to hard to put in. Yeah you'll run into some problems but the 427 will be bad. Shelby and his crew even had a hard time putting the 427s in their cars. One reason 428s outnumber 427s by a whole lot.

Yeah big blocks were an option in 67/68 so you can do it with stock parts even. It is tight to work on, but it will fit. You will need a BB C6 if you are going with an automatic and want it to last which are not exactly a dime a dozen, but they are out there....and will probably have to beef up the suspension while you are at it because of the weight difference of the engines....but again all that stuff is available. Good luck, will be a nice ride when you get done.