chagood said:
Yeah... Now I really do not know what to do. the 351 was just a really tight fit in the 67. I live in vegas so heat concerns me. I am looking for a car that is reliable with some umph off the line. Top end speed not as important. 302, 289, 351, 390??? Just don't know. And $$ is something I want to keep an eye on. Suggestions?
Personal opinion:
Stay away from the FE (390/428) unless you already have one. Cost is high to acquire, parts are relatively limited. I've owned two FE equipped cars, they are great motors, but Ford stopped making them in 1970, so they are slowly drying up.
Ditto on the 351C, unless you already have the parts, look elsewhere. The 400M is not good for car-performance applications, leave it in the trucks and 4X4s where you find them.
You can make unholy amounts of power, and parts are readilly available for the 385 series motors (429/460) but they ARE tight fits in your Mustang, and I'm just not a big-block kind of guy.
That leaves the Windsors (302/351W), these are the most popular, common, and are heavilly supported by the aftermarket manufacturers. The 302 is a great little motor, but if you stroke it to its limit it is a 347, the 351 starts with more than that and can go to 427 before you see the limit. Since you need to buy a block anyhow, I say go with the 351, thats what I did in my '67. Just find out how much more the block will cost, the only thing that costs more is the intake, and thats just about $10-20 more.
Of course if you want to have even more decisions, you could always go modular. But the 4.6SOHC/DOHC or the 5.4 will need chassis mods to fit.