Hi guys need some help on details for my build if you could. Im going for bottom end torque/towing and mileage. I've searched on the forums and found a lot of good info but nothing gets specific for my scenario.

I've got a 08 Ly5 5.3 with 243 heads, 1 3/4 longtubes, with high flow cats to single 3", air raid smooth intake with k&n drop in. Running stock converter with 3.73 gears. Not going wild on a cam, I've looked at BTR truck torque cam, specs if you Google it say 202/202 .507"/.507" 111-1 ( 112 ICL). It doesn't say exact specs on their website. And also sdpc truck torque cam 205/210 .550/.525 115. Definitely looking to mill the head .030 and maybe clean up the ports a little. Planning on changing to ls6 blue springs as well. Does anyone have any recommendations for a cam? And could I mill more and/or run a thinner head gasket since I'm not running a crazy duration cam?
Thanks

 

What compression ratio are you after??

 

with stock head gaskets milling .030 would put you around 10.5:1, you could run some Cometic .040" Head Gaskets and mill the heads around .036 to get to around 58.5cc and that would put you at 10.9:1...

 

Ditch the 243s and pick up 862s if you’re gonna be towing with it. You can still creep up to 220* AND tow. I’m running a 208/212 cam, 862s, long tubes, and a trailblazer converter in the 4L60E of my 08 avalanche. I towed a 4000lb travel trailer pretty regularly and it did just fine. Just don’t forget a decent trans cooler.

 

Thanks for the input guys, going for highest safe compression ratio for 91-93 octane. I'm having pcm of NC mail order tune, haven't gotten up tuners down completely yet. 10.9:1 seems like a safe number but I'm not sure about piston to valve clearance?

Why the 862 heads? The chambers are slightly smaller but milling 243 will put me below that. 862 have slightly smaller runners and intake valve. I could see how that would increase velocity with slightly smaller runners. Wouldn't a 220 duration cam lose bottom end grunt? I feel like the truck now struggles below 3k as it is for every day driving. That could be the tune I guess. Sorry I'm not bashing you just trying to figure out the reasoning. Thank you

 

PTV should be fine with those baby cams, even with milling .036 and running a 040" Headgasket, but it never hurts to check

 

The converter will take care of the "bottom end", like...below 2500 rpm.

 

Your lethargic feeling now could be due to crappy spark map or torque management.

 

You want more torque but use such a small cam. Thats not going to get you what you want no matter the head.
The cathedral will be the best as far as hitting a goal of good bottom end and torque but the cam is the issue.
I would recommend the stage 2 high lift from Texas Speed with the pac1218/1219 spring.
You can mill .020 off the 799s if you want. Just dont expect too much from small cid small bore and still lowish cr.

 

Building a hotrod tow rig limits your choices and you're spending a lot on parts and machine work with minimal gain.

If it's in the budget find a standalone tow vehicle (or hotrod).
Then you can ditch the hitch and set yourself free.