What heads for LS MOTOR????

Nolkemper622 · Jan 22, 2016

Alright boys I'm putting a 5.3 in my 1999 Wrangler and was curious what heads you guys are running for the factory castings? I came from the drag racing scene where the factory 243s port and polished were the way to go if you didn't want to spend $2500 on a set of CNC heads, I already bought another set of ls6 243 heads, but looking at all the bouncers I'm seeing a lot of them guys running 317s??? What's the scoop boys lemme know thanks

pholmann · Jan 22, 2016

243, 799, or 317. The 243 is off an ls2/6. The 799 heads are from an l33 all aluminum 5.3. The 317 heads can be found on all truck 6.0 motors 2000-07. The 317 heads have a little more combustion chamber than the other two though so compression would be probably the same as what you have now. The 243 and the 799 heads are identical except the 243 heads come stock with the yellow valve springs that are good up to a .550 lift. Hope this helps.

Ps...don't bother porting. It doesn't do ****!! And don't go over a .550 lift cam with stock heads. They actually back up on flow numbers past .550. If you need any help, advice, or parts just give me a shout. I'll help anyway I can.

Nolkemper622 · Jan 22, 2016

pholmann said:
243, 799, or 317. The 243 is off an ls2/6. The 799 heads are from an l33 all aluminum 5.3. The 317 heads can be found on all truck 6.0 motors 2000-07. The 317 heads have a little more combustion chamber than the other two though so compression would be probably the same as what you have now. The 243 and the 799 heads are identical except the 243 heads come stock with the yellow valve springs that are good up to a .550 lift. Hope this helps.

Yes exactly, these 243s came off a 6.0 gto with low miles, just curious why most guys are running the 317s then the 243s if the 243s put out more power and flow higher numbers why not 243s, has to be some reasoning behind the buggies running 317s

pholmann · Jan 22, 2016

They flow the exact same amount. The 317 comes factory on the truck motors and are very upgradable

Jduck · Jan 22, 2016

Nolkemper622 said:
Yes exactly, these 243s came off a 6.0 gto with low miles, just curious why most guys are running the 317s then the 243s if the 243s put out more power and flow higher numbers why not 243s, has to be some reasoning behind the buggies running 317s

Because that's what comes on most of the engines and people don't want to spend the money on other heads when these work just fine.

Technician · Jan 22, 2016

Put that bitch on giggle gas and let er eat!!

Bumpers · Jan 23, 2016

Re:

243s are the best cathedral stock castings out there
. As mentioned the 317 and 243/799 heads are the same only difference being larger combustion chamber on the 317

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Nolkemper622 · Jan 23, 2016

Thanks guys gonna be tearing down the motor soon and port and polish these heads and let them flow some higher numbers and put a specd cam in there from Martin Smallwood along with supporting mods and let her eat!!!

pholmann · Jan 23, 2016

Save your time and don't worry with porting and polishing. A good multi angle valve job will be your biggest gain. The numbers pre porting and post porting are disheartening. It's a lot of work for less than 15 cfm gains. Trust me. We've been there. This isn't a home port job either. By a professional head porter that has done it everyday for 30 years on super late model engines. The numbers were shockingly unimpressive.

87_bigbadzuk · Jan 25, 2016

So if you say stay with the stock heads what else do you recommend doing to get a lil more woopow out of the 5.3. I'm currently installing a 5.3 and haven't go the cpu tuned yet because I'm not sure if I want to run it stock or mod it. Its a 04 yukon 5.3. I've read cam swap intake swap headers and so on but what's the best bang for the buck so I'm not throwing 1k away for 5hp

Bumpers · Jan 25, 2016

87_bigbadzuk said:
So if you say stay with the stock heads what else do you recommend doing to get a lil more woopow out of the 5.3. I'm currently installing a 5.3 and haven't go the cpu tuned yet because I'm not sure if I want to run it stock or mod it. Its a 04 yukon 5.3. I've read cam swap intake swap headers and so on but what's the best bang for the buck so I'm not throwing 1k away for 5hp

you cant go wrong with a cam long tube headers of some sorts and a converter to match the powerband