I know you want to keep the 413 but in reality you could buy a rusted out P pumped 12 valve truck for $5k or less and swap the engine and trans and be money ahead even with a trans overhaul and good converter.

"Follow me the wise man said, but he walked behind"


'92 D250 Club Cab CTD, 47RH conversion, pump tweaks, injectors, rear disc and hydroboost conversion.
'74 W200 Crew Cab 360, NV4500, D44, D60 and NP205 divorced transfer case. Rear disc and hydroboost conversion.
2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.