The late 1970s up to the mid to late 1980s, I made the mistake of buying one and trying to use it It was horrible
Sent to a local good converter guy in SO CA and he fixed perfectly

I, we, (I was helping Steve and Linda Myers) started NHRA drag racing in NHRA "stock" class in 1973, we approach Art Carr and several other converter and tranny companies in SO CA for a full or partial sponsorship.
Art made us a deal on sponsoring us on the tranny maintenance for that year (1973 or 1974, CRS) if we bought one of his 8-inch race converters. That converter was .3 to .4 ET slower than the stock 11 inch Street Hemi converter and 3 to 4 MPH slower in the 1/4 mile also, what a piece of Shitt
We messed around with him for a full year on that converter and finally bought a Rossi converter and picked up near .5 ET and most of the lost MPH from the stock converter
I ended up buying a GER for a friend for his SB and testing in one my BB bracket cars, it was no good, ended up taking it to Munsiger and he fixed up good
My message is buy the best converter you can get, not any of the cheaper ones