[b-man]

Yes, a pre-'63 389 block will be a bit of a hassle, no starter mounting provisions and varying designs concerning block to transmission bolt patterns.

If you're up to making up adapter plates then the earlier blocks are an option, but most of us are looking for an easy bolt together conversion.

My take: look for a '74 or earlier 400 block, they typically have a better amount of metal in the lower end of the block compared to a 389. If you use a 389 you should be okay if you aren't making more than about 500 HP, but look for a '64 -'66 block if you decide to use a 389 block.

[Sirrotica]

Originally Posted by b-man

Yes, a pre-'63 389 block will be a bit of a hassle, no starter mounting provisions and varying designs concerning block to transmission bolt patterns.

If you're up to making up adapter plates then the earlier blocks are an option, but most of us are looking for an easy bolt together conversion.

My take: look for a '74 or earlier 400 block, they typically have a better amount of metal in the lower end of the block compared to a 389. If you use a 389 you should be okay if you aren't making more than about 500 HP, but look for a '64 -'66 block if you decide to use a 389 block.

Bart, 64 is the better block, 65-66 have thinner castings and the cylinder walls are definitely thinner than 64. I had one 65 389 .060 over that the cylinder wall collapsed and the piston migrated into the water jacket making for a bunch of cast iron and aluminum shrapnel. Wondering what went wrong I did some investigating and found that Pontiac cut iron from the 389s starting in 1965 through 66. This was around 1971 before sonic testing was widely available for block thickness testing.

Agree that 67-75 400 non 557 blocks are the best basis for the intended build.

I've done the 63 Tempest conventional driveline swap and removing a transmission tunnel from a donor car is less labor intensive than trying to make one from sheetmetal. I used a 60 Ventura tunnel for mine.

Sounds like a nice car you've thought out, good luck...............