Cam timing...

[shgrrttn]

Im building a more or less stock 71' 351c-4v with cc heads. I may run a hotter cam in it and maybe some hooker comps but thats about it. Right now, I am wondering about the cam timing. Im leaning towards advancing it 4 degrees to bring the powerband down a bit in the rpm range as I dont plan on running at high revs very often. Does anyone have any advice or experience doing this on a cleveland? If so, what are the positives and negatives I can expect if I play around with this.

 

[TommyK]

Im building a more or less stock 71' 351c-4v with cc heads. I may run a hotter cam in it and maybe some hooker comps but thats about it. Right now, I am wondering about the cam timing. Im leaning towards advancing it 4 degrees to bring the powerband down a bit in the rpm range as I dont plan on running at high revs very often. Does anyone have any advice or experience doing this on a cleveland? If so, what are the positives and negatives I can expect if I play around with this.

Advancing or retarding a cam is a tuning tool used when the cam specified doesn't perform as expected, or when 60 foot times vs MPH are an issue. Degree the cam you choose per the manufacturers specs and chances are if it is correct for your combo you won't have to worry about advancing or retarding the cam timing.

 

[shgrrttn]

Cool, I was planning on doing that.

Im building a more or less stock 71' 351c-4v with cc heads. I may run a hotter cam in it and maybe some hooker comps but thats about it. Right now, I am wondering about the cam timing. Im leaning towards advancing it 4 degrees to bring the powerband down a bit in the rpm range as I dont plan on running at high revs very often. Does anyone have any advice or experience doing this on a cleveland? If so, what are the positives and negatives I can expect if I play around with this.

Advancing or retarding a cam is a tuning tool used when the cam specified doesn't perform as expected, or when 60 foot times vs MPH are an issue. Degree the cam you choose per the manufacturers specs and chances are if it is correct for your combo you won't have to worry about advancing or retarding the cam timing.

 

[Jeff73Mach1]

I'm running a 4V CC headed 73 motor, lower compression than a 71, but otherwise pretty similar. I have a Comp cams 282 solid lifter cam.

It runs well, but the powerband as you can guess starts to hit hard around 4000 RPMs. That is what these heads are made for. they will not perform as well at low RPM's simply because the large ports aren't designed for that. you can band aid it and try and make it something it is not, or you can embrace its strengths and work them to the max. If you don't plan to run at high revs often, pull the heads and stick some 2V heads on the engine.

 

[c9zx]

Im building a more or less stock 71' 351c-4v with cc heads. I may run a hotter cam in it and maybe some hooker comps but thats about it. Right now, I am wondering about the cam timing. Im leaning towards advancing it 4 degrees to bring the powerband down a bit in the rpm range as I dont plan on running at high revs very often. Does anyone have any advice or experience doing this on a cleveland? If so, what are the positives and negatives I can expect if I play around with this.

Advancing or retarding a cam is a tuning tool used when the cam specified doesn't perform as expected, or when 60 foot times vs MPH are an issue. Degree the cam you choose per the manufacturers specs and chances are if it is correct for your combo you won't have to worry about advancing or retarding the cam timing.

+1 on TommyK's post. Without degreeing the cam you really don't know where you are starting. With all the possible "stack-up" errors (crank keyway, cam pin, timing set) cams can be way off. If you can't degree the cam and you are willing to do the work, you can take "a shot in the dark". Assuming everything else is working properly, if the bottom end is really soft and you are willing to give up some power at the top end, advance the cam 4 degrees and see what you get. I would check timing, advance curve, ignition system, and carb before messing with the cam. Chuck

 

[droptop73]

X2 on degreeing the cam. The cam I inherited with my engine was installed "straight up". When we rebiult the shortblock with a new timing chain we discovered the cam was 11* advanced at the zero mark. we ended up retarding the cam 7* to get it in at the 4* advance I wanted. No wonder it had detonation problems.