5.3 ls out of a 03 tahoe z71 with 706 heads for boost

[69trk]

will these heads be ok with a turbo? I found a complete 5.3 with computer, harness and everything for $450 and it has the 706 heads on it.... I plan on putting a 75mm turbo on this motor, but didn't know much about these heads.....

[BR3W CITY]

its the older truck head.
706 heads
Intake Valve Diameter: 1.89 inches
Exhaust Valve Diameter: 1.55 inches
Stock Head Flow Numbers
Chamber 61.15 cc----0.100--0.200--0.300-- 0.400--0.500---0.550---0.600
Intake 200 cc----------63 ---128----179-----210----218----221-----226
Exhaust 70 cc----------54 -- 93 ----121----145-----163----168----174

Not exactly the king of the hill when comparing flow numbers to other castings.
I have heard of people porting them, but for the cost and availability of other heads its probably not worth it.
IMO you can throw a turbo on anything you want. It might not like it quite as much as a 4" bore motor would, since the compression is higher, but with a good tune i see no reason why it wouldnt' work.
iirc there was a member here with a stockish 5.3 and a s400, i think it was a light blue truck but I can't remember his name.

[6.0 1955]

Be sure and open up the top ring to around .025-.028 to allow for expansion. The 706 heads cc is around 59-60. A set of 241's or even better yet the 243's will lower compression more with larger combustion chamber and will flow better as well. But if low boost is all you want to run bolt the 5.3 in hook it up and have fun. Good luck with the build.
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[69trk]

looking at 6 to 700rwhp.. will the 243heads work with the truck intake? or will i have to change intakes? thanks

[6.0 1955]

243's will work with truck intake.
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[BR3W CITY]

not sure how far you are willing to go into the engine, 6-700 is pushing stock internals, although some guys on theturboforums have pushed some wicked stock engine setups.

I see it this way; since it doesn't have the 4" bore, going will any of the "big" heads is pointless. They will flow more, but since you are creating your own atmosphere (and the issue with shrouding the valve) it won't be THAT great. Plus the larger combustion chambers will lower c/r and require to you run more boost to make the hp.

stock 5.3 with high vol oil pump and rod bolts, boost cam/springs/pushrods, + turbo kit and good exhaust and tuning should see 500's, more with meth.

IMO for 6-700 you may need to go a little farther. There are guys with the boost turned up who may argue, but I don't like to run my engine "maxed" out.

[69trk]

thanks for all your help.... I think i might do some rods and a few other things, just trying to get all the advise i can, being i'm dumb when it comes to turbos lol......

Originally Posted by BR3W CITY

not sure how far you are willing to go into the engine, 6-700 is pushing stock internals, although some guys on theturboforums have pushed some wicked stock engine setups.

I see it this way; since it doesn't have the 4" bore, going will any of the "big" heads is pointless. They will flow more, but since you are creating your own atmosphere (and the issue with shrouding the valve) it won't be THAT great. Plus the larger combustion chambers will lower c/r and require to you run more boost to make the hp.

stock 5.3 with high vol oil pump and rod bolts, boost cam/springs/pushrods, + turbo kit and good exhaust and tuning should see 500's, more with meth.

IMO for 6-700 you may need to go a little farther. There are guys with the boost turned up who may argue, but I don't like to run my engine "maxed" out.

[Narxoleptic Customs]

There are a ton of these threads on ls1 tech. 600 rwhp is alot! Before u start buying parts, it sounds to me that u need to do alot of research.

Also, r u ready to spend $800 on a converter, $2000 on a auto tranny, and another $700 on rear axle? The key to making that kind of power reliability u need a very very good tuner, so plan on $700-1000 just for that. Another $500 for dyno time too.

Here is my list that I am putting together.
Ls6 intake - $300
Cam - $350
Springs - $120
Tb - $200
Hptuners - $500
5.3 complete - $600
Turbo - $600
Piping - hot -$150
- cold -$175
Intercooler - $250
Bov - $100
Wastegate - $150
Dyno time - $500
Tuner - $500
Ls9 gaskets - $175
Injectors - 80+ lb - $400
3 bar map sensor - $325
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[69trk]

here's what i have already...

5.3 with harness- 450.00

hydraboost brakes system 831.28

ls radiator with fans 789.00

shifter with bootcover 231.95

procharger bov 200.00

procharger intercooler 1100hp 400.00

turbo 400 with brake new 1050.00

rearend with moser 33spline axles 841.81
full spool

3.5" aluminum driveshaft 1350ujoints 348.00

aluminum fuel cell with 10an hose
and 8an return aeromotive a1000 1300.00
pump



i'm ordering the turbo tomorrow... it's a borgwarner s400sx75 1.10ar t4 housing 83mm wheel 922.50

still having engine work done to the motor i bought, not sure on cost yet, will know tomorrow

still need wastegate, not sure what i'm going to do with computer and harness yet... torq converter, underhood repaint and turbo plumbing, plus alot of little things like motor mounts, spacer for trans to mount to motor, fuel pressure regulator etc.etc... i'm figuring this is going to cost around
12k or so....

[BR3W CITY]

ur heads in the right place, and it sounds like you know what kind of cost your going to face.
tial makes some badass wastegates and bypasses, pricey stuff but VERY good.

[low69chevy]

I say you should be good with that for now I'm building pretty much the same setup as you I got my 5.3 I'm planning on running a precision billet turbo/ built 4l60 w pi multi disk in my 69.

There's a guy down here running a stock bottom end 4.8 with turbo went 10.9@120 letting off cause he didn't have a cage.

My other friend is running a 5.3 billet precision67mm in his 95 silverado w/about 12psi and feels pretty strong sure feels like a 11sec pass when he guns it.
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[Shon]

I would find a set of 317s (cheap) and turbo it!!
76-78mm will make 600-700 to the wheels.
and as for the rings, I really would not tear down the engine to mess with the rings unless you are going to do more work than just the rings, plenty have went straight from junk yard to frame and turbo to track and went FAST.

As for cam, if you off the shelf the Z06 cam is most popular and can be found used. otherwise get someone to spec it out for you and have fun!!!