First of all i wanted to say what David said, we're not in any way bashing your truck. You do have everything to go much faster. i would make sure the timing is set 34/36 degrees. I still think it's a converter issue. I too think the truck should run 5.50/5.80. The ladder bars are not your problem and the 4.30 gear is about right for the HP. The pics i've posted below are of a 1951 ford truck with the original frame and ladder bars, it's all steel except hood with the original glass. It does have a strut front end. It has a 572" on gas no nitrous and a PG with 4.30 gears. It weighs 3,000lbs plus, he's a good friend of mine so i'm familar with the truck. The last time out at Twin Cities La. (local track) he ran 5.39@127 carrying the wheels 200 ft.
By the way i love that track you were at , it's the kind of track i grew up running many yrs. ago, kinda country and narrow. If you go back this weekend try the trans brake if you get it fixed, try somewhere between 3600/4200 with it. That may show you a lot about the converter.
Zip.
