Need help with ID on a 350 throttle body injected I've just bought.

Problem is mainly with the suffix code, I can't find a reference to it anywhere on the sites I know.

Larger engine number stamping is K 1025TPM and smaller engine number stamping is CK7134###

Engine casting number is 10054727, "5.7" and "Canada" near engine casting number.

Date code on cylinder bank of block is K21 ( Nov 2nd 1991 ?? )

One site says the block is a 1989 to 1993 , Roller cam, one piece rear crank seal etc

The heads are casting numbers 14102193 date code on one is K20 (Nov 2nd 1990 date code ?? ) other is K19 (Nov 1st 1989 date code ?? )

Described as being 1987 to 1995 1.84 inlet 1.50 exhaust with high swirl ports, centre bolt valve covers.

But getting back to the main question,

Can't find any reference to the suffix code to find out what it was originally out of.

Want to either fit a quadrajet with adaptor manifold to these later heads or fit earlier heads and an early manifold and Quad as well as a freshen up inside, nothing major and no big $$$ parts.

Will eventually pull it down for a post mortem so I will eventually find out whats inside in time.

Constructive help appreciated