Iirc, the factory specs for valve lash are .010 intake and .020 exhaust. The Erson cam I'm running suggests .022 all the way around on the spec sheet. Any ideas on why this would be and/or how critical it is to follow their suggestions?

Good Morning

Factory specs are for a factory cam. If you change to an aftermarket cam, follow their specs.

Yo could always set the aftermarket cam to factory specs and see how the motor performs........

Exactly. The lash should be compatable with the clearence ramps on the cam lobe. The cam grinder, knows best. Changing the valve lash (within reason), can be used as a tuning aid. Less lash, less bottom end (more chance of burning valves), more top end. More lash, more bottom end torque (more chance of "hammering" components), less top end power. Also the cam can be advanced or retarded, from manufacturers spec, to chance the power curve. Advanced, moves the curve down, retarded moves the curve up. Whenever installing a cam, it should always be degreed in.

_________________
Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Where does that leave us who never heard of degreeing in cams when we rebuilt our engines with new cams (not stock)?

Jerry

_________________
There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.

The cam may or may not be installed, in the optimum position. There are manufacturing tolerances that can "build up". Crank keyway, crank sprocket keyway, hole in cam sprocket, and the cam itself. If each item is off by 1 degree, in the same direction, that could produce an error of 5 degrees. Some timeing sets are made with the intent of changing the cam timing, for emisions, on later engines, but are sold to fit the earlier engine, also. I have seen cams degree in, up to 10 degrees off (on the dots). The engine will, still run, and maybe OK, but if you are spending money for a performance cam, wouldn't you want to get all the performance, you're paying for?

It is still possible to degree in the cam after the engine is built and in the car. It is harder, but doable.

_________________
Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Well, as you might understand, I'm not really too enthusiastic about the prospects of tearing everything back down to degree a cam right now. We've just finished a three-year build of Aaron's car, and it's pretty exciting to have it running fine for now... well, just a little hesitation, but we haven't made the final valve lash, timing, and carburetor adjustments.

I would like to spend some time to learn more about it and prepare to do it at some point in time. Same goes for recurving the distributor.

Jerry

_________________
There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.