c66vet

I am planning to install a different engine Block in my car. The clutch mount boss on the block does not have the hole drilled to mount the clutch bellcrank ball stud. Is there anywhere I can get the specifications on depth to tap etc.. I have looked at some other blocks and some of the holes are off center , does this have any effect on the operation of the cluch Z bar? The Block is a Bowtie 10051107, I am assuming that all 66 Corvette Big Block components will mount correctly. Any help is greatly appreciated, Thanks

knight37128

If you can find someone to drill and tap the outside of an iron block; let me know who/where.

There is a Z bar conversion piece that bolts up.

http://www.sdpc2000.com/catalog/1006...l-Brackets.htm

67L36Driver

Edit:
Refer to post below. Wrong hole, that's one of the oil cooler/plug holes.

I see the correct hole but there is no reference dimensions. You could scale the drawing but that would be a crap shoot.

c66vet

The boss for the corvette clutch bar is located at 11PM above the rear freeze plug. I do not belive these measurments are for that location. This is good information, thanks.

JohnZ

The Z-Bar ball stud has a 1/2"-13 thread; on original blocks, the tap drill hole is 0.86" deep, tap depth is 0.70".

c66vet

Thank you for the technical detail. I have been on the internet all day trying to find this information. My next step was to call GM.

buns

I'm confused by this statement/question. It sounds like you are suggesting that drilling and tapping a cast iron block is difficult.

knight37128

Bingo.

New cast iron is not difficult. Old cast iron will crack. Most of the outfits (that I have seen) heat it in an oven before any work is done to cast iron.

JohnZ

They wouldn't have been able to help you anyway - there's nobody left there who even knows what a clutch cross shaft ball stud IS.

JohnZ

That's a new one on me - true for weld repairs with nickel rod, but not for machining; never heard of having to oven-heat an iron block before drilling/tapping/machining.