A 54 is equal to a 61; the 62 has a P trim turbine which is one step bigger. I ran one for about 4 years and loved it. First 3 yrs were with a modified stock 2800 stall 12" converter and that isn't enough. From a dead idle the boost would crawl to 5, gently rise to 10, then snap on around to 20+ about 1 second before the 1-2 shift (2.4 60's). I went to a Yank converter, about 3200 stall (27-2800 rpm at zero psi boost) and it spooled like crazy. From a dead idle the boost would be 20+ before the car moved 5 feet. A friend ran one with an Art Carr 16930 3000 stall and his spooled the same way, so I really don't think you should go looser than 3000 stall (why give up the top end?). If you start tuning for pump gas 93 octane then 50's won't be enough injector, and 60's will be barely enough. At the track on race gas with higher timing the 50's will be close to maxed out. I believe in having more injector than turbo so I'd go at least to the high impedance 57's, or to the high impedance 60's.
