Originally posted by White Sands
Also the idle is around 800 in park but hard to nail down due to the cam. It jumps around a little. Is it normal for an engine with a bigger cam to fluctuate the idle speed and have the timing mark at idle move a little. I remember when it was stock the timing mark looked like it wasn't moving. Now it isn't as steady.

Fluctuation with any non-computer engine is pretty normal.
Bigger the cam and carburetion, the higher the fluctuation levels are - in my experience.
Although the dual quad big cam setup in my Buick engine mentioned above was pretty steady at 600 rpm.
I'm guessing due to the 118 and 112 degree lobe separation in the two big cams I ran it it. Both cams were about the same lift and advertised duration. Duration being 284 & 292 degrees intake and exhaust.

The 118 degree cam idled a little smoother than the 112 degree cam did, but both idled at 600 rpm.
Racing cams as you probably know have 104-108 degree lobe separation angle. The wider separation figures of 110 and up calm down the cam at idle to a great degree.
As does running a particular cam in a large CID engine.
A cam profile that idles well in my 462" Buick may be a lumpy son of a gun in a 265" SBC.


Part of what you're seeing at idle as pertains to fluctuation could also be attributed to a slightly loose chain. One within ok parameters. They all stretch a little bit at first. Even the very high quality chains.


I wouldn't tear down a good running engine just to find out what's inside.

If you're curious about how big the cam is, set up a dial indicator to read lift on either the lifter side or the valve side.
Be sure to take into account the rocker arm ratio if necessary.

If that's not convenient, pulling a cam in most cars isn't too difficult.
Remove the cam, bolt a degree wheel on it, set it in V-blocks and set up a dial indicator.
That'll tell you exactly what you want to know.
Again, don't forget to take rocker arm ratio into account.

Your ID'ing the cam may be made easy once it's removed by finding the cam grinders marks on the back end of the cam.
You can translate from there.

If the marks are unreadable - somewhat common - you'll have to revert to the V-block/degree wheel mentioned above.