327/350 Cam, Staight up or advanced?

[Scott G.]

I am in the process of replacing the aftermarket cam in my 327/350 with the stock GM cam. What is the prevailing thinking on degreeing this cam. Should I install it straight up or advance it? If advanced by how much?

Thanks,

Scott Goings

[Roy B.]

Re: 327/350 Cam, Staight up or advanced?

I might be missing some thing here , but your cam gear and crank gear have a dot on each that MUST be facing each other.
These set the cam and crank timing. What do you mean straight UP.

[Roy B.]

Re: 327/350 Cam, Staight up or advanced?

I might be missing some thing here , but your cam gear and crank gear have a dot on each that MUST be facing each other.
These set the cam and crank timing. What do you mean straight UP.

[Scott G.]

Re: 327/350 Cam, Staight up or advanced?

Straight up = the cam to crank relationship is factory specification (dot facing dot)

Advancing the camshaft means the camshaft is advanced a few degrees vs. the factory specification. The gear set may accommodate this or it can be accomplished by using an offset key on the sprocket.

[Scott G.]

Re: 327/350 Cam, Staight up or advanced?

Straight up = the cam to crank relationship is factory specification (dot facing dot)

Advancing the camshaft means the camshaft is advanced a few degrees vs. the factory specification. The gear set may accommodate this or it can be accomplished by using an offset key on the sprocket.

[Duke W.]

Re: 327/350 Cam, Staight up or advanced?

Consider that the duration at .050" lifter rise is 224 degrees and the centerlines are 114 ATC/114 BTC. The L-79 cam is 221 degrees with centerlines of 110/118, so the L-46/82 cam has marginally more duration and is retarded four degrees relative to the L-79 cam.

If you advance the cam you will have a bit more low end torque at a slight sacrifice in top end power. For the way most of us drive these cars the additional low end torque will be more useful.

If you pocket port/port match the heads and do a three angle valve job and advance the cam you will end up with more low end torque due to the advanced cam, and will have more top end power due to the head mods, which will more than make up for the four degree earlier inlet valve closing.

Duke

[Duke W.]

Re: 327/350 Cam, Staight up or advanced?

Consider that the duration at .050" lifter rise is 224 degrees and the centerlines are 114 ATC/114 BTC. The L-79 cam is 221 degrees with centerlines of 110/118, so the L-46/82 cam has marginally more duration and is retarded four degrees relative to the L-79 cam.

If you advance the cam you will have a bit more low end torque at a slight sacrifice in top end power. For the way most of us drive these cars the additional low end torque will be more useful.

If you pocket port/port match the heads and do a three angle valve job and advance the cam you will end up with more low end torque due to the advanced cam, and will have more top end power due to the head mods, which will more than make up for the four degree earlier inlet valve closing.

Duke

[Bryan L.]

Re: 327/350 Cam, Staight up or advanced?

I agree with Duke. I learned early on to advance the cam on a 302 Z/28 motor to give it a little extra low end. Low end torque is king on the street.

BL

[Bryan L.]

Re: 327/350 Cam, Staight up or advanced?

I agree with Duke. I learned early on to advance the cam on a 302 Z/28 motor to give it a little extra low end. Low end torque is king on the street.

BL

[Scott Marzahl]

Re: 327/350 Cam, Staight up or advanced?

My gear set had 2 degree advance available so that is what I used along with cleaning up the valve pockets and a good valve job. I can't wait to drive it.

[Scott Marzahl]

Re: 327/350 Cam, Staight up or advanced?

My gear set had 2 degree advance available so that is what I used along with cleaning up the valve pockets and a good valve job. I can't wait to drive it.