87gtNOS

Hey guys, I can probably easily find myself some heads from a couple friends with junkyards.

For my N/A stock cube C5, do I want 317, 035, 243 or 799 heads?

I assume all are aluminum.

For the LQ4/9 heads, what needs to be done to use them?

For the 243/799...I read that some have longer valves....does this mean pushrod length changes?

How much hp can be realized at the time of cam change on 241 castings vs. these listed above? If it's 20hp...is that worth it?

Thanks

kris6868

I would love to see the answer to this question as well..

I have a FI setup an a buddy gave me the 317 heads an told me to research them for a FI setup. The research i came up with is that the 317 works with LQ9 gaskets an work well on stock bottom end an a budget build. I have not installed them..

But i am very curious to what answers you get to your question...

87gtNOS

keep in mind...I am running just on the motor...whereas, I am pretty sure these are great heads for FORCED INDUCTION!!!!!

Sinister-one

you'll want some 243's or 799's.

chevylad

Somebody on this forum did a comparison of the 243 heads vs the stock ls1 (I don't remember which one). It only turned out an extra 5hp. It was the cam and intake that did most of the gains on a LS6 vs LS1.

LQ9 heads are the same design of the 243, but it is a 72cc combustion chamber so on an LS1 you will be losing almost a full point of compression. That's what a lot of guys running superchargers are doing, but on a NA engine it means losing horsepower.

vettenuts

I remember that post and simply have trouble believing the results. GM wouldn't have developed a new head for the Z06 for 5 hp. Also, there was a recent change in the 5.3 Silverado motor (well maybe a couple of years back) and the change to 243 heads made a considerable HP increase.

Of the heads listed, I would go with 243 from an LS6 for the lightweight valves. Second choice would be 243 with the standard valves.

BaadGoat2006

243's and don't look back.

87gtNOS

Alright, I have my guy checking on 243/799 castings...

On a budget....should I bolt these on (of course a check over of them) or have them milled and a valve clean up??

Secondly, what kind of HP does the typical 243 head and cam (with LS6 intake, ported TB, LT's) make to the wheels?

Do I need to buy Trick Flow heads to get 500 rwhp on stock cubes?!?

Thanks for entertaining me!

nobreaks254

"on a budget" and "500 rwhp on stock cubes" dont go together.

87gtNOS

Yeah...but do Trick Flow 215's and a cam around 600 lift get 500rwhp?

06x6spdGTO

Lot of variables in your head choices. 317's are pretty good for "higher" boost applications as they are similar in design to the 243 (c5Z06/LS2GTO) heads with a larger combustion chamber for a lower Static Compression Ratio (72cc untouched). 799 are almost identical to 243 heads in combustion chamber size but I believe the 799 has a smaller intake valve to avoid valve shrouding in the 5.3L trucks. If your looking for 500rwhp on buy some 243's and cam and add a small hit of N2O. As for just add Trickflow 215's and a Cam also add FULL boltons and up the compression in your trickflows to around 11.0:1 SCR.

Just for an example my C5Z made 446whp/406wtq SAE corrected on a Dynojet 248H. With stock sodium valved 243 heads milled down to 62cc Chambers, a 233/239 598 603 cam, Kooks 1 7/8 LTs, Catless 3in Xpipe, B&B catback, Slp 25% Underdrive pulley, and slightly ported LS6 intake. my Static compression is around 10.7:1. This was all done on 91 octane fuel.


Personal opinon is why try and push your car on a budget??? Get Junkyard heads, then a good valve job, add pricey aftermarket springs, get expensive pushrods, then install on your car expecting AWESOME numbers?? Do some searching on this forum as well as others for a decent used set, or buy some brand new ported LS6 243's and know you have a good product. It will save you time in doing the job twice. By all means I'm not saying to go blow 2.5K in a set of All Pro or AFR's but shop for whats better in the long run to meet your goal.

One more idea, if you can get some 243/799 heads dirt cheap, ask a vendor if they will change out 2 or more sets of cores for a discounted price on a finished ported product. I.e you send 3 sets of junkyard 243/799 heads in they knock off $300 to $500 of a finished product ported 243 heads.

nobreaks254

500 rwhp needs ported Fast intake, good heads, cam in the upper 230's duration min., big headers and exhaust, and most importantly it all has to work together. This is just my opinion, I have only built 3 LS motors for myself.

TriplBlk

From what I've seen 500rwhp on a stock cube LS1 is hard to accomplish on a budget. 450-475rwhp is more realistic IMO. 500rwhp is easier with stroker motors from what I've seen.

06x6spdGTO

My car has all of the above. Made 463/418wtq SAE Corrected. The ported Ls6 intake made 446/406. If you want 500whp better bump that compression up in the 11.0:1 + range and get some pretty damn good heads!
But I have only tuned and built a half dozen of LSx motors now!

Honestly if 500whp is your goal go with a set of Trickflow 215's or AFR 205's around 11.2:1 Scr (on stock pistons you'll need around 58 to 59cc chambers) Ported Fast 92, Kooks or American Racing headers, Underdrive Pulley, and a custom ground cam. That would probly put ya damn close to 500whp.

Or just throw a cam in it some budget headers and a 100+shot would get ya over the 500whp hill!

87gtNOS

So I have probably landed myself some 243's.
While we are in the junk yard, is there an Intake manifold and throttle body I should scoop?

LS3 and TB?????

Thanks

06x6spdGTO

An LS3 intake will NOT work on 243 casting heads. Look for an LS2 Throttle body and then buy yoursellf a FAST 92mm intake.

To make the LS2 TB work you will also need the wiring harness.

87gtNOS

What vehicles can the LS2 TB be found on?

Does the LS2 intake work on 243's?

87gtNOS

ttt...

Does the LS2 intake flow like an LS6? Afterall, the TB is bigger right?
Does the LS2 intake bolt to the LS1 motor with 243 heads?

nobreaks254

LS2 intake is not as good as the LS6.

LS2 intake fits any ls1 head including 243's.

87gtNOS

ok, but it has a 90mm tb? So it should be a better intake/tb combo than the stock ls1/ported stock tb combo on a budget?