Stock 5.3 cam has -37.5 at .050

Yes I typed that write

191/190 duration and 114lsa

 

And there we have it. Stock cams are off idle torque monsters with great emissions and driveability but zero fun up top.

 

Making it more simple instead of injecting more numbers etc etc just get the TSP Stg2 High Lift or stg3 high lift and call it a day. The truck intake has long runners for a reason and because of that it wont want much above 6k with good torque cams or even med sized cams for trucks. Running a wide lsa to prevent overlap on a larger duration is chasing you tail. Cut either of those on a 112 and they be plenty of fun in a 6.0. The lower cr of lq4 will reach a point of diminishing returns soon after that Stg3 down low. The stock trans shift rpm is 5200 to 5600 anyway so get a cam that is usable.
Either one of those 2 would be fun all around.
If you want more mid range and a more aggressive idle then our High Lift Hot cam. Has -1* of overlap but makes good torque still. Would peak somewhere around 6100 in a truck setup. Drives easy and idles pretty good.

 

OK- one more dumb question; what do ya mean by -2 +2? Now I feel like I'm on another mission, and that's good...........

 

Thanks, RPM- not looking into wide LSA's. Gonna look to keep in the 112 111 LSA area. I've looked at the TSP cams, not into the high lifts units but also compared the Stage 1 and 2 and just can't justify the bigger cam for 6 horses at the top and another 1.5 lbs ft of torque. I'm looking for that Iron Headed LT1 SOTP kinda torque. Don't see myself going over 5 grand.............

 

Thanks, RPM- not looking into wide LSA's. Gonna look to keep in the 112 111 LSA area. I've looked at the TSP cams, not into the high lifts units but also compared the Stage 1 and 2 and just can't justify the bigger cam for 6 horses at the top and another 1.5 lbs ft of torque. I'm looking for that Iron Headed LT1 SOTP kinda torque. DOn't see myself going over 5 grand.............

 

The high lift cams gain quite a bit vs the low lift. Stg2 cams for example
426/411 for low lift 6100 and 4800 rpms. 437/418 on the high lift 6200 and 4800 rpms. Thats on a gen4 5.3 with higher compression and nnbs intake. You can expect that cam to peak in a 6.0 with gen3 truck intake around 6k.

You cannot compare JUST peak though. Youve got to look at the gains over the entire graph as well as how well the graph carries vs the others. It may make more gains than what peak is and quite often thats what happens. That is only at 1 specific rpm. Total gains vs total gains is what to look at.

I may be able to get an overlay of the 2 graphs vs each other next week.

An iron head lt1 vs an alum headed lt1 is a turd, but both are outmatched by the tpi with its long runners as far as instant tq. 2 completely different intake designs. And it shows.
Bring your cr up and itll help. So would a 4.030 or 4.040 bore as well.

 

Easy way to do it, (intake+exhaust)/2 - LSA*2 = overlap

So lets say you have a 220/224 on a 112

(220+224)/2 - 112*2 = -2 overlap
(191+190)/2 - 114*2 = -37.5 overlap (stock 5.3 cam)
(230+250)/2 -117*2 = 6 overlap (my cam)

 

Really appreciate this, guys. I know I'm prolly makin' a bigger thing outta this than has to be- I have Vizards book on the way. Might even get me to change around my valve events too...............

 

You're definitely overthinking a single aspect of it. All the specs work in unison... don't focus solely on overlap.

Overlap is a part, albeit a large part, of how a cam behaves. You need to define your goals before you even look at cam specs. You need to ask yourself what other modifications you're going to allow yourself to do.

Answer things like this:
Do you care about how it sounds?
What do you use the truck or car for?
Any inclination how high you are comfortable revving on shifts?
What other mods? (things like a converter and headers play a large role in cam selection. Obviously if there was a power adder or ported heads in the equation it will change even more)
How many miles do you drive this thing?

The answers to those questions will help someone zero in on exactly where they want to place the valve events - When the intake valve opens and closes, and when the exhaust valve opens and closes.

Valve overlap will have meaningful effect on your engines ability to properly fill the cylinders (directly effecting the torque output) at certain RPM's, but it comes at a cost, and as I said before its only part of the equation.