Hi MGONCHAR,
I know your 67 Camaro very well. I would install a TKO-500 or TKO-600 into your car in a heartbeat.
I developed and installed the first GM Tremec 3550 into my 1968 Z-28 back in 1993. With the overdrive I was able to reduce engine speed 32% from 3000 rpm to 2040 rpm. The TKO-600 has a 36% overdrive and reduces rpm from 3000 to 1920 rpm.
This is a bolt-in that can be done in less than 3 hours on your garage floor if you know how to work on cars. The only delay would be to shorten the driveshaft.
BTW, The T-56 requires much more modifications and really isn't worth the extra cost and labor in my opinion....
Call me with any questions or price quotes.
Mike Forte
mike@fortesparts.com