I dunno about "lots", but more. Mine's .513"/.533", advertised 276/284, duration @ .050" 234/242, 110° lobe separation, RPM 2200-6400
Calculated static is 9.8:1, dynamic with that cam is 8.2, and I still pull a couple degrees of timing to keep it happy on 91 octane in the summer with those iron 308's.
I would suspect that has a fairly small cam too yeah?
Nothing wrong with the M1. I don't think you're going to find a ton of compression to warrant some big single plane intake and a big cam for a big high end number. I like the Eddy Air Gap better than the dual plane M1, but it's not a huge difference. Not worth swapping over I wouldn't think.
"doesn't have anything past 5,100" is probably a few things
First, the operating range of your cam is 1,500-5,800. So, not a giant cam to expect a big top end number, it's supposed to be all in at 5,800. I'm assuming this is the MP cam you've got- .450"/.455", advertised duration 268/272, duration @ .050" 228/231, 110°. The MP cams are ok, but there are newer grinds that perform much better than the old "purple cam" grinds. I like the Lunati Voodoo cams personally, but people are funny about camshafts.
Heads are next. You still have the small valves so 1.88/1.60, plus maybe some kind of porting that might actually be hurting you. A badly ported head will flow worse than stock. "Some porting" for me is code for "some previous owner screwed around with a dremel". Maybe not. But if it was professional they usually give you a number. IE, stage II porting, flows 264 cfm @ .500", that sort of thing. And if someone payed for that they usually know what they got. Anyway, if they left the small valves in there they probably didn't do much porting either.
The valve springs are singles with dampeners. There's a few varieties with varying spring pressures, but any of the singles are going to be kinda borderline with that cam. The Lunati I listed above that I run in my 340 requires doubles and more seat pressure than any of the MP singles with dampeners can give. The video didn't sound bad like you had a ton of valve float, but they may not be helping your situation either.
Compression ratio. You obviously don't have an 11:1 static. If you put 11:1 pistons into a 360 and they sit close-ish to the deck and then you use a set of heads with 67cc chambers (which the 308's could easily be), well, your compression ratio isn't even 10:1. The 308's on my 340 are 65cc chambers after everything was done and the heads were cut, and the pistons I run are .018" proud of the deck. And I'm at 9.8:1. If you don't have a ton of compression, you don't want a bigger cam to blow off more compression.
Report back after the compression check, if it doesn't crank at 160 psi or better you're going to have some work to do if you want add a bunch of power.
