What is the difference between a 65 400 block and a 66-67 400 block? Any disadvantages of using a 65 block? Was thinking about using 69 C heads with the 65 block. Thanks

 

I think it's the lifter bore diameter and angle. I know the 67 block is .921" bore and 39º angle and I think the 65 is .842" bore and 45º angle.

The 65 block has the more common and cheaper lifters but you would need to have a cam custom ground for 45º, which I have read here is simple (just tell the company you need 45º) and only slightly more cost that an off-the-shelf cam.

The heads will bolt up with no issues but you may need to verify the push rods don't rub on the holes due to the different bank angle. I have heard it's easy to open the holes to prevent push rod contact.

 

The casting numbers and letter next to the oil filler tube are different, if that matters to you.

 

I agree with Fun71, I did find an off the shelf cam for my rebuild but they aren't as common and it was a little more expensive. The factory intake was also a square bore pattern in 1965.

 

Correct, except that the 1966-67 E-block uses 0.921" lifters and 39 deg bank angle, to correct your typo. 65 uses the common 0.842" lifters but the uncommon 45 deg bank angle.

 

Does anyone know how much the pushrod holes have to be opened up? For a basically street engine, do the C heads perform much better than the early A heads that are currently on this motor? Thanks again

 

I think it's 9/16

 

Thanks Joe, apparently I have a sticky key on my computer.

 

You may or may not have to open the pushrod holes. You can just elongate the holes where the pushrods rub (at the deck end of the holes) as needed with a carbide bur/high speed grinder.

 

I would build the A heads, should be similar to C heads. Just use 2.07"/1.625" valves, if they don't have them already. A much better block to build than the later 400.

 

A heads also have the advantage that they are already tapped for 3/8" rocker studs.

 

Thanks everybody