69 427 Block question....

[John P.]

When the blocks were first machined did the plant know before they machined them if it was slated for a automatic or a stick?

The reason I ask is I'm searching for my block and I have a 4 speed in my car, So were all the blocks drilled and taped for the clutch linkage ball??

If not then that means if I find a good block I am going to have to drill and tap the block....

johnny

[Robert C.]

Re: 69 427 Block question....

All blocks with the same casting number should be the same configuration.

[John P.]

Re: 69 427 Block question....

That's what I figured I just wasn't sure
I mean they would probably all go down the assembly line get the same machining just to make it go alot smother and of course quicker!

thanks
johnny

[Craig S.]

Re: 69 427 Block question....

I am not sure about 1969 blocks, but for 1966 at least, the 942 block casting was used for both the 425 HP 4 bolt main applications with provisions for oil cooler plumbing above the filter boss, and for the 2 bolt main 390HP version, which did not have the drilling for the 4 bolt mains or the oil cooler. So, the casting was the same, but, the machining operations were different. I suspect this may have been true in 1969 also. A real easy quick way to tell is to look at Alan Colvin's Cheverolet or Corvette by the numbers books....Craig

[Craig S.]

Re: 69 427 Block question....

However, with respect to the automatic vs manual drilling of the pivot boss, I don't know, my only point is the casting number does not mean that the machining operations are the same down the line....Craig

[John P.]

Re: 69 427 Block question....

I hear what you are saying...
I havent hear back from my contact yet so I dont know if this block has this drilling done or not...
It is a correct date and corect casting for my car though so if I have to Im sure I can drill it if need be..

johnny

[Craig S.]

Re: 69 427 Block question....

Johnny - absolutely, I agree with you, that would be no reason not to get the block. It would be an easy fix...Craig

[Norris W.]

Re: 69 427 Block question....

I have 5 69 big block cars (along with a 70 with a 512 block also) and with 3 of the 6 being non original engine, I've spent a good bit of time/effort hunting correct blocks over the years. I've never seen a block that wasn't drilled for the clutch ball. The blocks with the same casting numbers are used for both 2 and 4 bolt applications, with the difference being in the machining process after the determination is made. The four bolt blocks got drilled for the extra main bolts, drilled and tapped for the oil cooler lines above the oil filter, and chamfered in the tops of the cyl's on the intake valve side for unshrouding of the intake valves. Although all the 396 blocks seem to have this unshrouding chamfer, the 2 bolt 427 and 454 blocks do not.

[Clem Z.]

Re: 69 427 Block question....

the smaller bore of the 396 requires the notch to clear the valve

[John P.]

Re: 69 427 Block question....

Could you send me any pictures of your 4 bolt block so I can see the difference they have to a 2 bolt 512 block.

Im clueless on the chamfer on the top and the oil cooler holes please if you can send some pictures to powersjk@nassau.usmc.mil

thanks

johnny

[Norris W.]

Re: 69 427 Block question....

Johny, I'm not sure that I have a block with the heads off now and the chamfer. I can look tomorrow, but the head gaskets are shaped to match this chamfer. It is roughly from the cut out on the intake valve side of the gasket down into the cyl, maybe 1/4 inch or so. As far as the holes above the oil filter, the bosses are already there and one is tapped for the oil pressure guage line. One of them gets drilled/tapped to 3/8 NPT, the other to 1/2 NPT. The rear one is the larger of the 2.

[Craig S.]

Re: 69 427 Block question....

Johnny - I will send you pictures of my 4 bolt 66 942 block, the eyebrows on the cylinders and the oil cooler drilling is the same....Craig