Thread: how to find a good used 390/428 block

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Rob sorry I just posted a link to the site not the classified ad. Thank you Denny!! I see you found the ad tho....worth a look for sure! At 4.250 the block is only .020 over. Some of those early blocks are thick uns and can go much more. If it's a 63 block there should be HP cast on the side,back and twice inside the block. Date code will tell you also. And crossbolt maincaps should be there!! And 63 blocks only have the 2 bolt motor mount bosses. Not a problem for the mustang either and easy to remedy. That block will also have press in freeze plugs not screw in so ask to drill bit test the block. The block at that price might have been windowed and repaired. But if done right not an issue. I had one old windowed block I ran for years. And as a 63 427 it will have a certain casting number and not generic. If you want you can PM me and I'll send you my phone number if you want to talk. I can fill you in on other details and give more info. It was the much mythed W code mustang that had the 427. Supposedly these never came to be. But you can never say never. There were some dealers who installed them. On pg 2 on that forum there is an ad posted by Dan Bell for Robie Ford. A dealer who installed 427's in mustangs. Very interesting. Seems he's not firm on the price either. Bring a dial caliper with you to measure the cyl bore. If you don't have one Home Cheapo sells them for $30. Good to have.

Early topoilers oiled just fine. They have larger oil passages than other blocks and also have a oil pressure releif valve. These are also solid lifter only blocks. You can use 390 heads on them. The 427 300hp marine version used 390 heads,intake and internals. CJ sized valves would help with a little port cleanup. You don't have to break the bank on a 427 build beleive me!! Lots of options.

G.

Denny, Glenn,

Thanks for the posts. I did some reading back in my Mustang manuals etc and you are both right on that the 427 was offered as a W code 390 hp, 10.9: 1 only in 1968. A 428 was not offered in 1968. In 1969 it went to the 428 and 429. Hhhhmmm.

Rob