I think if I was going to go GM, I'd use a TH2004r. It's small & uses a standard 'kickdown/pressure' cable, no electronics issues. Pretty low first gear, 2.75 or so. I've rebuilt several over the years and they hold up in low 12 sec. GM cars, so far anyway. It should fit the tunnel with no problems which would be the only reason I wouldn't use the mopar od trans.