How'd you think this setup would pull? LQ4 in a 2500HD
 

243's, long tubes, 212/218 low lift, tune? I'd consider adding 4.88's or 5.13's later on as the tire size increases ...

I've got another car that I go fast in, really just looking for some more grunt for when it's pulling stuff around.

That would do well. 243s would be a nice bump in compression

214 views and 1 response? Lots of interest, it would appear.... ;)

Depends on how much of a compression bump the 243s give you, are you okay with switching to premium fuel? Then I would say that's a good combo. If you want to stay on regular unleaded, just throw in the cam and leave the 317s.

I already run 91 in it, so that wouldn't be a problem.

Would I need a looser converter or would the factory one work OK with that cam?

212/218 is a baby cam for a 6.0. No converter necessary, but it wouldn't hurt

A converter is always a great ugrade and especially with a cam. A 2800 or 3200 will be nice for pulling with that cam. The truck will also shit and get empty. Big trans cooler and let her eat.

As for 5.18s they would be a bit much unless you are on a larger tire then stock.

Thanks for the feedback. Going to pick up some 243's on Wednesday.

I'd only do 5.18's if I go up to 37's again.

Should pull really really well. As mentioned more compression would be good. If you want to keep your heads milling the stockers is a cheap simple option.

Well, shit.

These heads I agreed to buy were 706's, not 799's. It was a 3 hour drive, and the guy waited up until 9PM to sell them to me, so I picked them up anyway, but are these worth a damn? Preliminary research suggests that they will still increase compression a bunch, but have smaller intake and exhaust ports, which will choke the truck after 5000rpm or thereabouts?

Nope, no choke with that cam. I've got 706 heads on my 6.0 towing build. 2" intakes put in and bowls blended, and the chambers unshrouded for the larger valves. I'm running a Vinci 210/218. Stock 3.73 gears, stock converter, long tube headers. If the truck was newer or I was planning on keeping it longer I'd do 4.56 gears but as-is, it pulls very very well. The compression bump is the main factor below 3000 revs in my opinion, but mine pulls strong right to my 5800 rpm shift points. 243s are likely better, but I got my heads for $25 so that's what I used.

That's good news.

I figure worst case scenario where I totally hate it, I can put my 317's back on if things don't go smoothly. It's not like the heads are super hard to get at.

Will probably keep my eyes open for some 241/799's anyway, but I'll keep these on the shelf if something doesn't turn up soon.

Would you consider running them with the factory sized valves?

I didn't. And wouldn't.

Sounds about like my build.
Still in the works though.
Got the block out yesterday and hits the machine shop tomorrow.

I email Cir D and the response I got was basically using a stock converter but with 2A stall speed and some internal upgrades.
My truck is a 6500# Hummer H2 on 37's.
Once I get the motor done Ill be putting in gears.

Any progress? My 2500 wants 218 cam/ 243 head combo.

Howd it turn out?