CUMMINS, hands down!!

 

well to fit four adults nicely in your choices you need like a 95-98 stroker. Then jsut save up for a cummins swap later. that being said the older 7.3L ford is a work horse also

 

Yeah, if you go ford get a 7.3, you dont want the cost of maintenance on a 6.0. And the first true crew cab cummins was the mega cab. They didnt make any 4 door first gens, though there were a few centurian conversion crew cab 2nd gens sold at dealers. Dont wanna hijack the thread but if a quad cab 3rd gen will be big enough for you ive got mine for sale in the for sale section. And its already got a billet tranny so you should be good as far as the tranny concerns, until the 6.7s came out the tranny was always the weak link in stock form