Topic: 67 390 & C6

[scodemike]

I ran into an anomaly when installing my C6 Trans to the 390 Block.  I ordered bolts/lockwasher's to mate the two and received what Bill said was correct, 7/16 grade 8 bolts.

It turns out the threaded holes in my block are 3/8, not 7/16.  The engine/block is original to the car.  Anyone have experience with the 390 & C6, did they make a manufacturing change somewhere along the line.   I have done many 390's over the years, some with the C6, just don't recall running into to this before.  Just curious, I did install the C6 using 3/8 grade 8 hardware.

[68 S Code]

I don't think they were grade 8 originally. I ordered my set from AMK and they were zinc. Installed the C6 on weds without an issue with bolts but plenty of others, as flex plate (flywheel)didn't get installed on motor and was 200 miles away.

[scodemike]

But do you recall what size the attaching bolts were?  I used grade 8, didn't really cost any more and made me feel better.

[68 S Code]

Sorry didn't get the message till now and car is at another location. I will look tomorrow and email you a pic.

[68 S Code]

Took a look today and didn't find them at the garage with the car. May have left them at a third garage so I will look there tomorrow.

[scodemike]

Took a look today and didn't find them at the garage with the car. May have left them at a third garage so I will look there tomorrow.

Thanks for the effort.  As I stated in my original message I am just curious what other's may have found.