68 gt fastback 390 Swap Q's

Has any1 done this before? Any pointers tips suggestions please help I hate doing extra work!

Yes I know it's a stupid swap if you are looking at the value end of it but I am rebuilding the s-code motor to stock and slightly modding the Y-code motor. They are both 390's I was wondering if there was anything different on those motors such as clearance issues or anything like that. I have a S-code motor and am switching it out with a Y-code motor out of a 68 galaxie 500 it has factory air and I wanted to hook that up as well the mustang didn't come with it so I was wondering what I would have to purchase or maybe steal from the galaxie to make it work on my mustang.

I'm not quite clear on what your doing here?..Your just swapping your S code 390 out of your mustang for a Y code galaxie motor?..If so it should be fairly simple..One thing that may be a concern is the exhaust manifolds..I think you have the GT heads which have a couple of extra bolt holes over the galaxie heads..Depending what heads are on the galaxie you can drill and tap them...Don't know about the air stuff but I would imagine you could reuse whatever is on the motor and buy an underdash unit to complete the system in the car.

Originally Posted by K_Labs

Has any1 done this before? Any pointers tips suggestions please help I hate doing extra work!

Yes I know it's a stupid swap if you are looking at the value end of it but I am rebuilding the s-code motor to stock and slightly modding the Y-code motor. They are both 390's I was wondering if there was anything different on those motors such as clearance issues or anything like that. I have a S-code motor and am switching it out with a Y-code motor out of a 68 galaxie 500 it has factory air and I wanted to hook that up as well the mustang didn't come with it so I was wondering what I would have to purchase or maybe steal from the galaxie to make it work on my mustang.

As mentioned with the exception of the GT 390 "S" code head exhaust manifold bolt holes, it is dimensionally the same engine. Just use the mustang motor mounts and accessories off of your "S" code engine as mentioned. All bracket bolt holes should be identical. As far as A/C nothing except maybe the compressor and mounting brackets will work. If you want it to look original you would need to find the dash parts, duct work, A/C heater box and heater core and a 68 A/C under dash harness. Expensive!

If not picky go with the Classic Auto Air setup for early mustangs.

Nice pic

How about if I were to put on aftermarket heads would there be an issue?

Shouldnt be. They usually make them to factory specs. If you are referring to the Edelbrock FE heads they are similar to the 427 low risers. The accessory bolt holes should be the same.

My '68 FB has a Galaxie 390 in it. I used the 390 GT heads and manifolds, and there was no problem. Exhaust is pretty tight around the clutch linkage.
I used Mustang mounts.
My car was factory air, but I put an aftermarket R134 system in it.
I kept all the original AC stuff, though.
Greg
mbjeeper@aol.com