Corvetteoz

Hi all,

I's buying a new cam for my 350 soon and need some advice on the below results.

Looking at the dyno sheets of the Comp cams its interesting that the smaller cam of the 2 with exactly the same set up produced more power and torque.

Camshaft XE262H-10
HP-348HP @ 5300rpm with 415 ft lbs @ 3700rpm of torque

http://www.compcams.com/v002/Pages/387/XE262H-10.aspx

Camshaft XE268H-10
HP-342HP @ 5000rpm with 413 ft lbs @ 3800rpm of torque

http://www.compcams.com/v002/Pages/388/XE268H-10.aspx

My engine will not have as much work done to it as in the dyno results above. This has Dart alloy heads and I'm sticking with my original cast no.3998993 heads.

Could anyone explain why the smaller cam is performing better?

Gold Dragon

I am sure there are members on this site that have more experience with cams than I have but I will take a shot. I think the clue is that both set ups are identical and using a vacuum secondary carb. The bigger the cam the less vacuum you have at the manifold. If the examples used a mechanical secondary carb I think the bigger cam would make more power and the outcome would have been different. At any rate hardly noticeable at the rear tires.

Corvetteoz

I'll be using the original Quadrajet carby. I'm not sure whether it has vac or mech sec's but I'm leaning towards mechanical if I remember correctly.

I would be interested in more opinions on this matter but your explanation Gold Dragon does make sense.