Gotta add some more here on this subject.Gearing is usually the key to what kinda speed ya want to drive.My daily driver is an 03 Ranger,with a 4 cyl.and 5 sp.Probably 3.73 gears.It will run at any speed I want it to 70,or 80,even 90 it handles it just fine,and also gets 30 MPG which tells me that fifth gear is an overdrive.I am sure the old 216 sixes and especially the 235s have that kinda running capability if they are geared right.When these trucks were built they had 3:90 and 4.11 gears which means they are set up to run 45 to 50 MPH max.Put in a 3:08 or so rear,or an overdrive tranny and you will be set to run at todays highway speeds.When I first got my 55 it already had a 350 V/8 in it with an m22 4 sp.At 65 MPH it was turning about 2800 RPM and sounded like the engine was ready to blow.I switched to a 700R4 OD tranny and now it cruises at65 at about 1800 RPM,and is still using the original 3:90 rear.Seems to me that a way to much emphasis is put on how much power your engine has.I think Joker is running a T5 tranny and 2:72 gears in his 52 and has a nice driving setup.