Grand91 - thats not a bad time for a fairlane with a 351 !
my last car was a ZH fairlane running a overboared 351 ( estimates of 6.something litres) , c10 auto and the 3.90 diff and it was a fantastic muscle cruiser .. no sports performer at all - just grunt and plenty of it Handled like a turd - but hey its a luxury car - not a sports car
Considering that those cars weigh close to 2 tonnes ( mine was a fully optioned marquis ), to get a 14 is good IMHO..
Same motor in say a falcon ( xy XW ish ) would be doing 12's..
A 7mgte is a really nice setup i hear - bar that head gaskey rumour, and they are known to be a very hefty power unit when tuned and modded - looking forward to seeing it in your supra at a later date