SBC 400 factory/dealer rebuild?

[rfoll]

I picked up a small block 400 with all of the accessories and a turbo 350 for $250. The guy said it had about 72 K on it and it came from 1972 Bel Air he bought in 1978. I was quit possibly the dirtiest engine I have ever seen, and I considered it might be 172K for mileage. When we tore it down yesterday we found absolutely no ridge at the top of the cylinders. You can't feel it with a fingernail. The first thing that had me wondering is the red composition head gasket. I have never torn down an original engine and seen these. The connecting rods are numbered. It was still wearing a plastic timing gear. The rod bearings are factory GM. Despite having no ridge, the bore measures 4.127", which should be enough to show. Could this engine be factory or dealer refurbished?

[mag2555]

I know the Archaeology of things like this be interesting, but at this point does it really matter if you know where I am coming from?

[BillK]

Sounds like someone has been in it. I have never seen a factory Chevy engine with the rods numbered. If a dealer had done it they probably would have used GM gaskets so if that's not what the red ones are I doubt a dealer did it. I am betting someone just freshened it up somewhere along the way. The bores may very well have been at 4.127 from the factory.

The numbers stamped in the deck at the front will tell you what vehicle the engine was originally installed in.

[rfoll]

The numbers match up to the car he said it was in. The serial number on the trans matches the one on the engine. I know it is ancient stuff, but I know there were factory refurbished engines available from GM and it makes me wonder if I have one.

[SupStk]

Sounds like someone has been into it. If it has Moraine 400 bearings and especially if they are marked .0006 or .0012 on the backside, it would indicate OEM parts. Bearings weren’t available in those sizes at the dealership counters. The red composite head gasket makes me wonder if it isn’t a Victor replacement?
I was thinking 400s had their rods marked from the factory.
I worked as a tech at a Chevrolet dealership for 11 years in the 70-80s. Seen GM fitted blocks, short blocks, long blocks and complete engines but never had run into a GM rebuilt one while there.

[dwilliams]

Moraine 400 bearings and especially if they are marked .0006 or .0012 on the backside, it would indicate OEM parts. Bearings weren’t available in those sizes at the dealership counters.

I used to always check the bearings when stripping cores, and if they were still in good shape, I re-used a lot of those oddball shells and half-shells to get the main clearance just right. Back before .001,2,and 3 bearings were available, there wasn't really any other option, and the old shells allowed finer adjustments anyway.

[rfoll]

I only pulled one rod bearing and actually didn't care what it was after I saw the OE GM label. I would never re-assemble something like this without putting in new rod bearings, but it's likely this all happened when the engine was very new. Part availability is better these days. I suspect it had a blown head gasket, 400 engines were known for that. Lots of cross hatch visible in the flawless bores, but At 72,000 miles It's hard to believe it's factory.