273 Rocker on 340
I've been eyeing this cam but thinking maybe 108 centerline? Also maybe going solid. Expert I'm not.
340, 10 over KB pistons, 160 cranking pressure 10:1 Comp (I believe), Eddy heads, RPM intake, 750 ABS carb, Stock manifolds 2 1/2" Exhaust, 4 spd., 323 rear gear, 235/60/15 tire. Street car with some weekend highway cruising.
Also eyeing this one.
Howards Cams 718001-09 Howards Cams Rattler Camshafts | Summit Racing
Which cam?
IMO;
running just 160 psi with the alloy heads, would be a gross unfairness to them, as would running less lift than at least what the Edelbrock springs are capable of.
As to the 718001 cam;
Installed with an Ica of 68* the V/P ratio is predicted to be 126, about the same as a 5.2 Magnum, which is what it's gonna feel like under say 3000.rpm, so, yur gonna need to slip the clutch to get moving. and at just 105* power stroke, it will suck gas. But, it will make great power at about 5100, which with 3.23s/ your tires, is 46mph in First/87 in Second, and so you'll probably want more rear gear; like 4.10s and those will not like cruising in Direct at 65=3300
Whereas;
As to the 710461 cam;
Installed with an Ica of 64*, the V/P is predicted to be 137 which is getting torquey, the 3.23s can stay. and at 111* of power-stroke, she will use a lot less gas. This cam may power peak a few rpm sooner, but the advertised specs make it out to be a tad over one camsize smaller, increasing your Dynamic compression ratio from 8.08 to 8.37
But the good news is that this smaller Advertised spec cam, together with the longer Power-stroke, means that you could advance that cam to in at 61*, which would get you a CCP of 178psi, and a V/P of 145, with a Dcr of 8.54, and the Powerstroke ends up at 108* still better than the the 105 of the larger cam.
However;
IMO
this is a band-aid for not having enough Scr; 10.5 is NOT ENOUGH for either of these to optimize the cam install.
> the smaller ca wants 11/1, and
> the larger wants 11.4/1
In both cases installed at ~split-overlap,
the Pressure is predicted to be ~183psi, and
the Dcr is predicted to be 8.75.
But, whereas the bigger cam is predicted to make a V/P of 140, the smaller is predicted to make 145, obviously a 10% stronger bottom end.
Now, V/P is very important to a clutch car, on the street. The more you are able to run, the stronger the low-rpm will be. And with just 3.23s, your engine will not get to the torque until say 3300rpm which is 30mph, in First gear. So, you need all you can get.
Then, to get from a true 10.5, to 11/1, with a swept of 696cc, will require the total compression chamber volume be decreased from 73.3cc, to 69.6cc, which is just 3.66cc; but to run 11/1, you really need your Quench to be in the window of about, .028 to .045 and it is not advisable to run in the window of .050 to .080. So in your particular case with open chamber heads, this may not be possible.
IMO
between these two cams, I would run the "smaller" one, straight up to maybe 2 or 3 degrees retarded, at a higher pressure, with a tight quench. I think it may make very similar power than the bigger one, without the torque loss at lower rpm. I would run it with hydros and .5 turn preload.