6.0 capabilities

[RHYNO6.0]

I have a 98 trans am and recently purchased a 6.0 lq4 with the 317 heads. I planned on making a 408 stroker. Money is tight and I wondered if anyone here has an idea of the limitations of the stock bottom end of the lq4? It came from an 02 truck with 50,000 miles. Also if anyone has any suggestions I'm open for ideas!

[deuce_454]

you should be good to 700 Hp atleast... especially if you stay within a reasonable rpm range, its the rpm that kills rods, and your not going to break a 6.0L crank any time soon.. the 02 rod bolts are prety stout pieces and the 317 heads move lots of air..

i think you will benefit more from sending your heads out the be CNC ported at TEA or some other reputable shop and installing a cam to match your instead of blowing money on the bottomend that really doesnt need it, and heads and cam will gain you more Hp than the 10% cui you'd gain with a stroker crank.. remember that the Hp is made in the airflow, not displacement, id be surprised if you gained any top end Hp with the stroker at all without doung heads and cam also

and to all the people screaming torque, just remember that Hp is a function of torque and RPM, so even if the low to midrange torque is boosted by the full 10% its still not going to bend the seatbacks or warp time


i think its safe to say that you could gain the same just with a cam and tune

[WSSix]

Agreed. If money is tight, do not stroke the engine. Go with heads and cam along with the supporting mods such as headers. The stock bottom end of all LSx engines is really good. Change the intake and cam and there's no reason your 6.0 can't spin to 6200 rpm unless something is wrong with it of course. Just do not get into the bigger is better mindset with the cam or the heads for that matter. A simple port job and mild cam will do wonders for the engine.

[RHYNO6.0]

Thanks for the help, I have another question. Some shops are telling me to buy new heads instead of waisting money on porting the 317s. Any suggestion, are they right? And if so whats your recommendation on good heads that aren't mega expensive?

To inspect the 6.0 bottom end won't they need to disassemble it?

Sorry for all the questions, all the help is greatly appreciated!!!

[deuce_454]

wow a shop that sells heads told you to buy new ones... i can hardly believe it:D :D

the 317 heads are identical to the ls6 243 heads except combustion chamber size, if you send them out to a reputable shop (not TSP or patriot) like total engine airflow they can be CNC ported to flow like or better than a new set of aftermarket heads, and support 500 rwhp with a decent cam, with NO other changes... besides many of the performance heads you buy are cnc ported OEM castings unless you want to shell out upwards of 3 grand for a pair of CNC ported AFR's...

6.0L Stage 3
Lift Intake Exhaust
0.1 70.6 50.4
0.2 143.1 118.2
0.3 210.9 186.7
0.4 261.1 230.7
0.5 302.9 260.1
0.55 319 269.4
0.6 334 277.1

http://www.totalengineairflow.com/products/gmhead/gmls6/

another option is to not remove the heads at all (it will cost you a set of gaskets and cylinder head bolts to do so), and only replace the cam, installing for example a texas speed and performance tsunami MS3/MS4 cam will gain you over 50Hp and have a great musclecar'ish idle.. it costs about 700 USD for the cam, springs and pushrods, you will have to change the springs with the heads installed but it is the cheapest route.. and it will net you a 450+ hp engine for very little money

texas speed also sells heads that are cheaper than the TEA's but the quality of the work just isnt the same...

as for inspecting the bottom end, its a waste of good money to do so, you will drop the oilpan to change the cam and if you want to spend some good money you change to ARP rod bolts, that allows you to inspect the rod bearings (and they are never worn) and visually inspect the bores (they are also never worn) only thing you have to remember is to change the oil pickup o-ring... it costs about 2 dollars and it can (will) make a wierd sound if you dont... some people also swears by a ported ls6 oil pumo at this stage...

http://www.texas-speed.com/shop/categoryM.asp?MID=5&catid=44

[indebt69]

Some Patriot heads, a nice cam, and new intake will do enough. I've seen several articles about 6.0's with over 500 hp with the above combination or close to it. That's the setup I'm going to run except have AFR's and probably a G5X4 cam from LG. Along with LS6 intake, I'm shooting for 450 to the wheels (through a t-56). I did it with my Vette and a lil 346ci, so should do it with the 6.0

[Josh@KYTP]

6.0L .03 over
Mahle -15cc dish pistons
CAT 6.125 rods
Stock crank
ARP studs
LQ9 317 heads
LS6 intake
76mm Turbo at 15LBS of boost. 770rwhp & 778rwtq. Good times.

[1badchevelle]

thanks duece this will also help me on my build.

[RHYNO6.0]

I think I just want to sell the 6.0 and put heads, cam and intake on the ls1 with longtubes. Maybe make around 420 rwhp and then work on getting traction and a good launch from there.

[Bronco]

I think I just want to sell the 6.0


How much? And where is it? I might be interested.

[deuce_454]

you will make way much power on the 6.0 with the same mods, remember it has a 4 inch bore and take L92 heads, also it will idle better with bigger cam and you can run the Ls3 intake, wich prety much outflows a ported FAST intake...

also the Ls1 is worth more, so you will get more money from the sale of the ls1, and make more horsepower for the same or less money on the 6.0...

a heads and cam 6.0 is knocking on 600 Hp easy... thats a full 100 more than a simmilarly built ls1