I'm rebuilding the engine in my 79. compression is 9.6:1 ,stock heads mild ported with 2.02/1.60 valves, auto with 3:55 gear , stock manifolds with 2.5 duels The two cams I'm looking at are Both Comp Cams XE256h and XE262h , my question is how is the drivabilityof these,and how are they for vacum ?any suggestions?
If they are flat tappet watch out. The XE series of comp cams has been having many failures due to the extremely aggressive ramp rate of the lobes, even with people that use oils with enough ZDDP.
As far as the actual specs of the cam, you will be fine as far as idle, driveability, and vaccum go.
But if you want performance I would highly suggest some headers, you are leaving a good 15-20HP on the door with those stock manifolds.
Either would be fine. I lean toward the 262. There are many forum members who have the 268 or 274 cam in their vehicles. They are not too radical of a cam therefore it will not pull too much vacuum with good driveability.
I have the XE262H cam in my car. Very good vacuum with no drivability issues, although my engine is a 383. I use Valvoline racing oil (the one not recommended for street use). Four years with no problems.
There are many forum members who have the 268 or 274 cam in their vehicles. They are not too radical of a cam therefore it will not pull too much vacuum with good driveability.
With my 73 L82 I'm running a XE268 with 4spd, performer intake, headers and 2.5" pipes with Magnaflows. Nice Drivability, car idles at 800rpm & good performance Only vacuum I have to worry about is for my headlights (they pop right up!)