Before you start ditching parts take a good look. You mentioned swapping front end pieces. The 62 upper valance is different than 64. It's an easy fix though, the F O R D is spaced differently. I like the 64 valance better so it's what I used.
The Y block mount is pretty easy to weld on the front crossmember - just line it up with the 223's mounting hole. Pretty easy to remove from your 64 too, just cut through the welds on the top & sides and give it wack with a 5 lb hammer - comes right off, lol. I went through the same thing with my truck, but both ways - it was a 292 truck, I had a 223. I had to cut the mount out to drop the 6 in, then when I got a 292 I had to weld it back in place.
64 valance on a 62 Uni.



1964 F 100 LWB Roller 5.0 & T-5

2001 Jeep Cherokee XJ

2009 Harley FXSTB Night Train



"I still have a Y block - it's just not in anything yet."

Greg, you have a very nice unibody!  It looks like your headlight rings/trim are '64? 

I am going to use the '64 front valance with the 62 grille.  I like the 62 grille better. 

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.

Thanks

Those headlight rings came off a 62 parts truck with the grill. All Slick headlight rings are the same as far as I have ever seen - only difference is chrome steel - 61, or painted steel & aluminum.

My Uni is in the garage right now, total redo of the body, filled seams, shaved drip rail and new paint - same style. Working on the roof now.

1964 F 100 LWB Roller 5.0 & T-5

2001 Jeep Cherokee XJ

2009 Harley FXSTB Night Train



"I still have a Y block - it's just not in anything yet."