Over the 39 years that my '63 F100 Unibody has been in the family, it's busted over half a dozen motor mounts. Usually happened when someone was overzealous by shifting from drive to reverse or vise-versa while the truck was still rolling (Cruis-O-Matic trannies hate that and will show it by locking up the rear tires or busting a mount). I've replaced them twice in the 4 years it's been in my possession. Since then, I've added a torque strap, and don't let anyone drive my truck.

They aren't real hard to find, but to find correct ones can be a challenge. I recommend Topp's Auto Supply in Anaheim, California if you want good quality y-block mounts (and many other parts) for good prices. I don't know where you are, but I'm sure you can arrange for them to send you parts. Not even SoCal Pickups in Riverside, CA has the right engine and tranny parts (and they specialize in older Fords!). Topp's has never failed me when I needed something for my 292.

You say the old rubber mounts seem to be too large, well, that's prolly because they are smashed. They also may be foreign-made. There are many y-block mounts out there that are made overseas. They are not the right size, and use inferior bolts.

Topp's mounts are made in the USA, and use only Grade 8 bolts. Check 'em out.

-Zen-