I had a 78 nova that towed more stuff than most work trucks...
I scrapped iron and bought and sold cars , and pulled the boat to the lake often..
It was a 350 with a 268h and 72cc heads ported it ran 14.50's in the 1/4 with 308's ..that thing was a stump puller 20.5 mpg not a big cam but decent..
218-218-454-454 on a 110///
I swapped heads to some 186's and 54cc chambers and a 270h that is 224-224-470-470....
Much more cranking pressure BUT it was not as good as a trailer puller as the previous engine ...it was a full second quicker,
I bet the 268h with good heads would rock, especially with a few more cubes....
I run a 260h in an E150 and it is ok ,, but a little on the small side...or maybe 302's just suck
Do not get carried away with a big cam you will not like it for pullin'--
I would not go bigger than 218 at .050 for a puller