thanks ted.these caps are 2.100 at front 4 and 2 at the back.caps are marked CECG6325A on the front 4 and the back has a 9 on the end instead of 5.

For the ECZ block and ECZ caps I have sitting here, the front four caps are 2.275” and the rear cap is 1.950” measured from the bolt hole boss to the mating point at the block.

Lorena, Texas (South of Waco)

has anybody got a 312 main cap they can give me a measurement on.i need the height at the bolt hole.i have a 256 with 3 inch main bolts and tall caps and just wanted to see if their the same or how close.