Thread: Camshaft advice (again...)

Tweet

Originally Posted by techinspector1

Gus, I'm going to make a suggestion to you. If this were my car/motor and I was installing a 268 cam, I'd advance the cam by 6 to 8 degrees. The hotter cam (over the stock one) will retard the intake closing point, closing the intake valve later than the stock cam. This is going the wrong way with your very low static compression ratio. By advancing the cam on installation, you will close the intake earlier and capture more of the fuel/air mixture, giving a more favorable dynamic compression ratio.

This is never going to be a race motor as it sits and advancing the cam will give you more driveability in the low and midrange, where you need it for the street. You'll give up some on the top, but how often will the motor see time above 4,000 rpm's? Any cam you install will be a compromise in one area or another. The best you can do is try to get a little better performance in the range where the motor will be run most of the time.

If you're unsure of how to position the cam for advance, either ask here or PM me for a tutorial. I'll give you the straight scoop.

Use a degree bushing kit such as this and drill the pin hole in the cam sprocket to 13/32"....
http://store.summitracing.com/partde...0&autoview=sku

I.M.O.,if you have to advance a cam more than 4 degree's the cam is to large.

Get some Rhodes lifters,they bleed off duration and lift under 3000 rpm for better torque and dynamic compression.

Originally Posted by erik erikson

I.M.O.,if you have to advance a cam more than 4 degree's the cam is to large.

Exactly.....

Look at this Crane at 266 degrees ground on 110. Check out the recommended static compression ratio in the upper right hand corner, 8.5 to 10. That's a long ways from 7.83:1.
http://www.cranecams.com/?show=brows...tType=camshaft

Several members have suggested increasing the static compression ratio by thinner gaskets/head shave and I think that is valid advice. Shawnlee has come up with a great suggestion also, with the Rhodes lifters. I've used them and they work.

Pat thinks the cam will be ok straight up and has a lot more experience with big block Chevies than I do. I just know what the numbers tell me.