Project Muscrate:
The end is near!
Or is it the beginning?
| (above) The loaded block with lifters, and ARP head studs installed. One thing to remember with a 302 block is that the lifters MUST be installed before the heads due to the short deck height. |
PART 1
i everyone and welcome back! I know I’ve said it before but where has the time gone? I have a LOT of ground to cover this month so let’s get to it! Last issue I covered most of the bottom end assembly and said that I would cover degreeing of the cam this issue. Well, I changed my mind. I decided that the practice has been covered many times before, including by myself, and there is simply too much else to cover that is more pertinent.
I did, however, go through the process and ended up installing the cam at 106 degrees, which basically along with the Comp Cams billet 9 keyway timing chain with a Torrington roller bearing (part # 7138) ended up at what some people refer to as “straight up” or “0” advance. The cam card for my custom spec. Comp Cam called for it to be installed at 102 degrees which would be 4 degrees advanced. I almost never advance a roller cam in a racing application because I don’t want to move the “sweet spot” of the power band down in the rpm’s which is essentially what advancing a cam does.
Now for the specs. I had the cam made with the 351W/302 HO firing order of 13726548. The cam is a custom ground solid roller that I designed by going through the Comp “Master Lobe” catalog and by using a program called Cam Quest 6 made by Comp Cams and then I inserted all of the pertinent information about the engine into a computer modeling
program called Dynomation Advanced Engine Simulation with Pro Tools.
This is not your father’s computer dyno, this is a serious piece of engineering. I will cover this software in a later article along with a drag racing simulator called Drag Sim after what’s left of this season is over. Then we will be able to compare actual “on track” performances with what the software predicts I should have run. Should be interesting.
As for the cam specs, I used an Intake lobe from the “RC” series (#4185) and an exhaust lobe from the “Hi-Torque .420” series (#1660). These are some pretty aggressive lobe profiles, a “real man cam” if you will. The lobe lift is .435” In. and .420” Ex. When used with the Comp stainless steel roller rocker arms with a 1.7 ratio (#1134-16) this should give a gross valve lift of .740” In. and .714” Ex. The duration at .050” lobe lift is 268° In. and 275°Ex. with a lobe separation of 106°. The duration at .020” lobe lift is 298° In. and 307° Ex. The grind number for the cam is FW 4185F/1660F R6 if it ever needs to be duplicated.
