Summit Racing has Delco part numbers 24244046, 24244058 & 24244062 in stock, These are remanufactured for GM, Most will have a oversized TCC Regulator & Isolator Valves (.472"). This can be confirmed by the (SERV) stamped on the valve body.Wondering about valve bodies- any good quality sorces (besides sonnax's own reman) updated valve bodies- wondering if that is an option instead of dealing with existing one. Existing core is unknown- maybe good or worn.
'96-'08 valve bodies interchange, The difference is in the the Accumulator Valve & Accumulator Valve Spring. The Transgo SK-4L60E will allow you to tailor the Accumulator Valve to the 2nd Servo size via different weight springs.
If you're concerned about Line Pressure being applied to the converter clutch?.......This is probably the best option outside a Sonnax valve body, Then you can simply tune the PWM apply out (HP Tuners doesn't support '96 & '97 VCM's just so you know)
I'm not familiar with Fitzall products.