My old 62 Valiant, 225 & 4sp, 3.23 gears, would do 5,000rpm in 4th and that was 120mph. It wasn't all over the road either, very steady....helps when you spend a bit of coin on the suspension.
yes the suspension / aligment is 'key'
But yeah and your car weighs 2700lbs +/- and probably does not have ss springs sitting a mile off the ground and raked...
my 71 dart with 225 would also do the same as yours and not be all over the road, but this like you are saying-120'ish
