Porting 302's

I think the 714 is just an earlier variant that became 302 casting. They’re identical in every way that I can tell. One jasper rebuilt 318 I have had a 714 on one side and a 302 on the other. As far as guides; Most rebuilder 302 heads I’ve come across have had replacement bronze guides. The last core pair of 302 heads I sold to a member had a couple of those guides needing replaced, but those heads came out of trucks that probably had more abuse than use. The only ones I have know of having cracks have been because of overheating. As far as knowing if the heads will be an improvement, you answered your own question with the cam and intake swap conundrum. But it’s the same exact thing I would do, because I think what you gain on compression with the closed chamber heads you’ll give back on flow. But, with a little cleanup work,
The 302 fast burns will be a win. And aside from that, I also wouldn’t bother with changing heads first and then cam and intake later, because with the stock cement mixer cam, I doubt you would see any difference. I would run the comp 260 cam (440 lift and [email protected] on a 110). And I would get a torque converter that would compliment it. Not just any torque converter, but one that you talk to someone on a phone about. Precision of New Hampton will be the good. That should also be a lockup torqueflite, so that’s really a no brained when the budget allows for it. Of those carburetor choices, I would go with the smallest ThermoQuad of the bunch, but I would be more willing to use one of the Mopar HD truck QuadraJets based on my own personal experience in similar builds, or even on a bo e stock 360 HD truck engine. They work very well in heavy vehicles with highway gears. Use these head gaskets. 4 inch bore and somewhere close to .040 compressed thickness. Military surplus Dodge M880 gaskets.
New NOS Mopar DODGE PLYMOUTH CHRYSLER 318 V8 Engine CYLINDER HEAD GASKET 4186348 | eBay

A better head gasket for more compression would be what the factory used on 1986 and up engines with 714/302 heads. They’re of the same construction and bore size except for black gasket material and around .028 thick. I haven’t seen any bulk supplies for sale yet, but there may be some surplus items that will come up eventually. The Navy and AirForce (and maybe others?) used mostly Chrysler vehicles and Dodge trucks after the Chrysler bailout up unit at least 1987, so there’s some waiting to come out of a surplus sale sometime. I don’t remember you mentioning anything about exhaust, but this would be a very good place to use magnum manifolds, or even a set of eBay stainless magnum headers. If you go with the $100 Chinese stainless magnum headers, expect beforehand that they may need removed after about a year of use and the flanges reground parallel on your machinists table top belt sander.