Another gearbox identification question - SIIa/S3 Mongrel?

[Benny78]

When I got my '64, the gearbox was absolutely full of water, so I assumed it was scrap. A couple of years ago, I saw an engine/gearbox combo being sold by a guy who was stuffing a Chevy 350 in his 88". From memory, his truck was about a '70 or '71, and he claimed the gearbox was a S3 gearbox.

I believed him, because it had the S3 style clutch, with the slave on the left side, and a clutch lever. Someone recently asked me what the gearbox suffix was, and I found out it's an E suffix, which would make it a late IIA box. When I popped the lid off it, the internals appear to be identical to my "scrap" '64 gearbox.

So, what is this thing? My understanding is that the last of the IIA gearboxes were fully synchronized, but this appears to be a non-synchronized S3 box. Could someone have possibly failed their S3 box, and swapped in a IIA box behind their S3 clutch assembly?

Any advice appreciated.

[cedryck]

Unless I am wrong, I think it is entirely possible for someone to match an earlier box with a later clutch assembly.