I doubt it has a 460. It's most likely a 302 or 351. Just take a quick look under on the drivers side and you will be able to tell whether it's a small block or big block by the hydraulic clutch. The small block 5 speeds used an internal slave cylinder while the big block and diesels had an external slave. I just got rid of a 1990 F250 with a 5.0, 5 speed and 3:55 gears and it was a dog. Picked up an 84 F350 5.8 auto that has either 4:11 or 4:56 and it's a world of difference. I never liked those light duty 5 speeds because the slave cylinders never seem to last and you have to pull the tranny to change them. If you want to look for something on the island here I'd have no problem checking it out for you.
Lots O Trikes!!!!!
TRIKEFEST 03, 04, 05, 07, 09 Going the distance