trans options 454 c30

[bns454]

im after some advice on which trans to go with when I bought my 86 cc dualy it was fitted with a 200r4 that was missing 2nd gear in 4th its ratios seem perfict for the use my truck gets (mostley 75mph freeway use @1000rpm)
I pulled the trans and fitted a t400 that I had spare now the truck is at 3000 in top and the 454 wont live long term at that
the truck will be mostley used empty but maybe 3 times a year pulling a small speed boat. the options I have are to get the 200r4 repaired, fit a t700 (that I have already) or a 460le with a controller the truck is an 86 and came with a factory 4 speed auto
I have everything to refit the 200r4 and there is factory wiring for a 700 I assume still under the truck plugged into some boxes screwed to firewall (cruise control related maybe?) my main priority is to get the truck idleing at 75mph again the truck has 4.56 gears according to the spid