The exhaust manifold gets matched to the heads, not the intake manifold. Also, Cobra Jet basically refers to the block - the 351C 4V was a Cobra Jet (Q or M code I think), while the 351C 2V was not. You can't really turn the engine into a Cobra Jet, but you could replace the intake manifold, heads, and exhaust, and cam shaft, and make a faux 351 CJ.
Edit to add: there is nothing wrong with the 351C 2V engine, a lot of people think it's a better street engine because of low/mid-range torque. From what I understand, the 351C 4V Cobra Jet runs best at high RPM; i.e., at the track.
Oh ok thank you! Got some miss information there! Lol but sounds like 2v then! And ya ours is an H ans cobra is Q.
Also sense we would be doing the 2v sense the cobra is complete different then what we thought, in a as close to original restoration as possible, would an original 73 2/2 intake and carb be worth more to the cars overall vaule, or would there not be much difference between that and what is currently on it?
Those are pretty much bolt-on upgrades so I don't think it would affect the value much if at all. Really, you have to ask yourself why you're doing this...if it's as an investment, I'd bet you'll end up spending far more than its market value says it's worth. Do what you want and enjoy it for what it is...not for how much money it may or may not be worth.
Another edit: I believe that 4V and 2V refer to main caps. You'll hear them referred to as "4 bolt mains" and "2 bolt mains". The 4 bolt main caps were stronger, allowing for higher duration RPM use (racing). PLEASE if I'm wrong someone correct me. 4V and 2V do NOT refer to the number of barrels in the intake and carb NOR do they refer to the number of valves in the heads. Again, someone please correct me if I'm wrong.
There are many people on here that are more knowledgeable, I'm just relaying things that I've picked up on this forum. I have a 429, not a 351. Now that I think about it, maybe the main cap thing applies to the 429 family (TJ vs CJ/SCJ). LOL sorry if I've confused things.