this header requires the use of hooker transmission mounts · 1970-72 use rear transmission ... 12652 for turbo 350 · 1973-78 use rear transmission mount #12653 for turbo 350 120 will fit ... mount #12677 use factory stock rear transmission mount 133 header dual exhaust system ... front frame mounts #12609 and hooker transmission mount #12649 for turbo 400 powerglide ... and turbo 350 transmissions may use stock transmission crossmember ... the california vehicle code for 1975-82 chevrolet/gmc trucks and blazer/jimmy equipped ... of rear wheels 155 will not fit manual transmissions during 1971-76 156 long wheel base only ... not fit with muncie sm420 cast iron transmission 168 this is a tuned equal length ... of the shocks header will fit with c-6 transmission 176 this system has been designed to ...