Help me pick the right cam

[GregWeld]

Wait -- I'm confused -- you HAVE both cams on hand?? Or you have one of the two you listed and are considering using a cam that you'd need to buy?


#1 -- I'd take a cylinder pressure check and see how much pressure you're currently making....


#2 -- I'd jab the new cam and put the heads on and do another cylinder pressure check to see if the new combo is making more pressure.


You don't need the intake on for doing this - nor do you need headers etc.


The cam that comes with the SB383/435 motor --- GM shows you a HP/TQ chart for that motor - so you know where that cam is making power just by looking at the chart.


Here's why I suggest - if you have both cams - to do the cylinder pressure test --- because bigger cams bleed off cylinder pressure - but they make more HP on the dyno because they spin at higher RPM'S.... (therefore it MIGHT create lower cylinder pressure numbers).....

If I was going for some better bottom end power -- I'd want the cam that makes the higher cylinder pressure --- but has an RPM rating "close" to where the bigger cam is. The HP number on a dyno might not be as high because you'd spin it at a lower RPM -- but the TORQUE number might be higher/flatter - and fatter in the band that you want the motor to pull like a freight train.

Hope that makes sense.