I might be getting a 351 CJ and I dont know anything about these motors at all. Do these motors make some good power stock? I will do the basic for now a bigger carb and intake on it and some new wires. I want some power
The intake ports on the heads and the factory intake are as large as you'll ever need. You'll gain nothing but the weight loss in switching to an aluminum intake over the stock iron unit. Heads will be the open chambered 4 bbl ones, not exactly good with pump gas, they're prone to pinging more so than the earlier quench heads. Valve sizes in these are 2.19 intake and 1.71 exhaust. A good sized carb for one will be a 750 cfm. Headers will gain you some more, but not as much as other engine types would. All this is assuming that it IS a 351CJ motor with it's original 4 bbl heads.
thats going to be a tiiiiight fit in a '65. You can do it, but it will be a challenging project. Theres a fella on VMF who has a 351C in his '65, nick is "Dodgestang" Give him a shout.