390 into 65 mustang

The car will have to be altered regardless the motor it came with. The 390 is a lot heavier motor. It will not make a good handling car because it is extremely front end heavy. At speed you turn the wheel and you go straight- not good. The 390 requires that the fender liners be cut because the engine bay is too narrow but it will fit. You will also have to drill the liners to change the plugs. You could leave them off but it eliminates driving in the rain. I did help a bud do this mod to his 'stang years ago. It was not satisfactory and I don't suggest it. While a 390 in a small car sounds like a fast car- it ain't. The 390 is a truck engine. First came out in a truck tractor. It makes lots of torque at low rpm but it ain't no screamer. The motor has the limits of a 3 degree twist on thge rods which means you are not going to turn it very fast. It is and was designed to be a slow turning engine with lots of torque. And that is exactly what it is. I suggest that you would be happier with a 289/302/351 in you car and the mod would be by far cheaper.
Flash

Anything is possible...This has been my latest project going into year 5 now. 514 Ford Motorsport in a 1968 Mustang FB. Started with a $1500.00 wreck, and everything has now been replaced, newly installed or custom made and fitted in. As far as handling...all I need is a straight 1/4 mile.



Ron

Sure, you could make that fit. You would need to do a front clip, so that you could remove the shock towers to make room. Its the cost of what has to be done to the rest of the car to handle the power that gets real pricy. The subframe, the tubbing, the roll cage to tie it all together, the shortened rear end, the 31 or 35 spline axles with the 9 inch, the transmission, the custom cooling system, the remote oiling system, the modified pan, the front springs, the wiring, the gauges,the interior mods, the fuel system to keep it running, the brakes to slow it down, it needs a 6 inch cowl hood to clear the carb....It might be cheaper to build a tubular chassis, go all fiberglass.
The 514 (after some mods) makes 685 HP at 6250 and 610 ft/lbs of torque at 4250.

The engine is a Ford Motorsport crate motor, to which you still have to ad an oil pan, pump and pickup, starter, waterpump, carb and wiring. That alone ads up to about 11K.

Question is what would you like to do and how much HP are you looking for?

Ron

I did not see it answered above very clearly so I will add what I can. 65-66 never came with anything above a 289. 67-68 came with 390s and 428 (427,428,429 cant remember). The 67-68 cars were much bigger in the engine bay. 390s fit in those, but with next to no room to do ANYTHING. In regards to a 6 to 8 swap, most people will tell you that it is just not worth it due to the amount of stuff you have to change out, ALL suspension and brake parts, bell housing, (chuck the 3 speed manual if you have it), rear end.

Now your deal.

Major cutting on the front end will have to be done to fit that motor in there. I don't know the specifics, but it will be a lot of work that needs to be done by someone who really knows what they are doing (that may be you, I don't know)

Suspention will need to be found from somewhere, all VERY heavy duty stuff. I don't know of compatibility issues with later stronger stuff and the 65-66 parts that were never designed for bigblock use.

5 lug 4 wheel disk breaks will be needed.

9inch rear end/hvy duty rear springs shocks

must use either 4 speed toploader or c6 auto. The 3 speed man and the c4 are just not strong enough

Subframe connectors and a bunch of other frame support type modifications. Full roll cage would definately help. Again, this year was not designed for the weight and power of a big block.

The end result is that it would be MUCH cheaper to pick up a 67-68 v8 car and start from there on your project, but if you are willing to spend enough time and money ANYTHING IS POSSIBLE. But you may end up spending $25,000 on a car that will never be worth more than $4000. The fact that it is a 6 coded car and has then been cut and modified to the level that you are doing will be a harder resell than even an intact 6 cyl car. Just know where this will head in the long run.