[Mike Taylor 3601]

I would say springs are problem,6 cyl worn out springs, when jack the car up I'm going to guess the springs almost or do become loose,if that is the case front end extends and you run out of spring,they don't have any stored energy,when you pull engine probaly does'nt raise front of car all the way up against the stops.
You want springs that have to be compressed quite a bit to end install,but soft enough to let car down to ride height you want,like the moroso's
Then if you wheelie to big you can adjust,one thing is can raise starting line rpm sometimes and wheelie less,by puttting controled spin on at the hit.
Mike Taylor 3601