Mike, The one on the left is an 8 cylinder. My guess is mid 90's 454 Vortec truck motor. The one on the right has a 3 pin connector and that's it.
I did find the number 1104068 on it (the one on the right). I did a search for the number and came up with this:
GM Cam Sync distributor & 24 tooth crank wheel 1104068
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Price: $150
Part Fits: 93-02 Chevrolet Camaro, 93-02 Pontiac Firebird, Corvette, 04-06 Pontiac GTO, 04+ Cadillac CTS-V
Location (State): MI
Item Condition: Used
Shipping Information: Item Can be Shipped
LS Engine?: Fits LS Engine
GM Cam Sync distributor PN 1104068 used for SBC's looking to run a LS1 style system to utilize coil on plug ignition. Use this with a 24 tooth wheel (which I will include for free) and you'll be able to run the ls1 bs3 on your standard SBC motor.
Edit: The one on the left is PN 1104052 which is an optical dist for 90's big block trucks.