Cam experience please

[Mizark347]

On #1 cylinder about what time should the valve be opening on the intake stroke according to the balacer. Same for the exhaust stroke, about what point in time should the valve start to open or be fully opened? -according to most cams. Also should it be degreed differently for a 347?
Any info i could work with and would be very appreciated.

 

[Michael Yount]

The cam should be degreed in accordance with the info on the cam card. The engine it's in is irrelevant in that context. And you can't use the balancer and pointer as indicators of tdc for this purpose - they are too inaccurate. To degree one or actually measure the valve event timing, you have to establish actual tdc using a positive stop, and then use a dial indicator and a degree wheel for the rest of the measurements. Having said all that, most reasonably streetable cams in 5.0L based engines will have an .050" intake opening event somewhere between 10 degrees before tdc and 6 or 8 degrees after TDC. Most fall in between 5 before and 5 after.

One challenge you have is that you have a cam designed for 302 cubes in a 347 - so it's gonna behave quite differently in that displacement motor. Your cam card info doesn't do you much good. If that's what you're trying to get at, the only way I know how to go about optimizing your cam timing in that combo is either to 1) use an index set and experiment with different timings - and then dyno or track times to see what happens, or 2) pay someone like Ed or Buddy to model the set up, and let them run things 'virtually' to see how it responds to different cam timing.

 

[Mizark347]

I stalled it dot to dot and its way off....I knw im goin to have to degree it. I see 5.0 cams ran in high cube small blocks very often and just wondering if someone has experience with 302 cams in 347s and wondering what adjustments they made if any.

 

[Mizark347]

Degreeing a cam pretty much only checks it, right. Its pretty much a guess and check deal, correct?

 

[Michael Yount]

Not sure what you mean by your question. Degreeing a cam insures that the manufacture of the cam is correct, and that it is installed in a way that the valves are actually opening and closing when they're supposed to be. So, if the cam card says the intake valve is supposed to be open .050" at 5 degrees before top dead center, then degreeing the cam installs it in a way where that's exactly what's happening. Simply installing it "dot to dot" assumes that everything is completely accurate (cam, gears, etc.) which is rarely is. Most of the time things are within a degree or two, but sometimes, they are as much as 4 to 6 degrees off. Degreeing a cam assures that that kind of error isn't present.