M20 Muncie ?

69camaro76b · #1 12-19-2025, 01:50 AM

Found these stamps on my 69 M-20 transmission. Just curious what they might mean, if anything?? Thxs

**SS69chevelle** · #2 12-19-2025, 02:14 AM

XG is the code for a M20 trans, no idea what the heart is and have seen it on several cases. Might be a QC mark? If that is XC it indicates an M20 as well but it looks like XG to me.

**Kurt S** · #3 12-19-2025, 02:59 AM

The heart is an inspection mark - I've see others used too.
XC and XG are both M20 codes - what engine?

69camaro76b · #4 12-19-2025, 03:08 AM

I bought the trans by itself, don't know what engine. ID tag shows 3946797

**Kurt S** · #5 12-19-2025, 05:06 AM

That is XG then. From a Z28 or L78.

Can you post a picture of the date and VIN stampings?

Thanks!

69camaro76b · #6 12-19-2025, 09:01 PM

The transmission is NOS and never been in a car, so there is no VIN. The assembly date is P9M14. Does the blue paint next to the heart stamp mean anything?

**SS69chevelle** · #7 12-20-2025, 01:44 AM

Quote:

Originally Posted by 69camaro76b

I bought the trans by itself, don't know what engine. ID tag shows 3946797

info i have found in my 69 chevelle research for that number:

m20-tag 3946797- w/3.55, 3.73, 4.10 axle, 350/396 engines muncie

The Following 2 Users Say Thank You to Kurt S For This Useful Post:
lbnaz (12-19-2025), Pro Stock John (12-20-2025)

Dedicated to the Promotion and Preservation of American Muscle Cars, Dealer built Supercars and COPO cars.