Pretty much, still a nice upgrade though. I put LS6 heads on mine at a whole lot less money than aftermarket heads would have cost. I got a set off an '04 Corvette Z06 with just 40K miles from someone who spent big on aftermarket parts for his car. We just did a comp cams spring upgrade and cleaned them up. There are later model LS heads with the same castings (243's) that flow just as well and can be had for a few hundred bucks but the true LS6 heads also have the lightweight valves. My car made about 400hp/390tq at the wheels with these heads and just a cam and headers/exhaust system. The rest is pretty a much stock LS1 except for an LS7 lifter upgrade a set of hardened pushrods and a Katech C5-R timing chain. Being an '01 SS it came with the LS6 intake as OEM. Now that my curiosity is peaked I will have to see what I have for a block, it's the original engine with 87K miles.

 

i like the idea for those who are doing what you are doing the Y2K ,like myself i already got a cam kit saved to my wish list for an ls6 upgrade ,got the intake,nice thing is with that is one can do just the cam an get some hp ,but with the combo of heads cam springs ,the kit i am looking at has the push rods too an timeing chain too,but i may break them ,there are some selling the kit wich the cost has gone up alot one can spend 3 to 4k ,so i think it best to get everything thing but the cam kit seperate,the heads costing the most i would say ,i want to do it for around 2k at most thought ideas the cam kit is $800.00 so then some used heads mabey in good rockers too

i see a set or rebuilt ls6 heads for $750.00 is that a good price

 

It depends some on if they are genuine LS6 with the lightweight valves or just the 343 castings. The 343's flow the same and can be had used for around $300. $750 is a little on the high side but real deal LS6 heads are getting hard to find and if they are indeed fresh and ready to go on it's not bad, I gave $800 for mine and probably paid too much but they're in great shape and I was in a hurry and they were available. A real good deal would be $500-$600 I think. That said unless you plan on a real hi-rev motor you are going to pound on the plain 243's would probably do you just as well. I see them for sale all the time over at LS1 tech in the $300 range. Of course $750 is still a lot less than a set of Trickflows or something else aftermarket ,they may not perform quite as well but they will still give good bang for the buck on a budget build up.

 

?? how do i tell the real deal yes i may do that an look into the real deal though,an get the aluminum rocker rollers too ,i guess building up these top ends is so big couse the bottoms are so strong on them they say 600hp an 700hp for the stock crank so the 400hp +range should be good for easy thanks Y2K

 

Good question, the only reason I knew mine were was because they were fresh off an '04 Z06 Corvette LS6.
The light weight hollow sodium filled valves are a bit longer but not enough to even tell with the naked eye and of course you'd need the solid valves to compare to and have them apart. The best way still requires disassembly, they must be weighed.


GM numbers:243 heads

Stock LS2/1 etc. solid valves --intake 99 grams exhaust 86 grams
Stock LS6 lightweight valves --intake 76 grams exhaust 63 grams


Here's some good reading... https://ls1tech.com/forums/generatio...id-valves.html

 

The tuner that did my work told me not to waste my money on roller rockers for a 400rwhp build. They won't give enough hp to make a difference and to really need them you'd need a motor with a bottom end built for really high rpms well past what a stock LS1 can spin.
As for the light weight valves, it's said they are good for about 5hp tops so you need to ask yourself if you want to spend the extra money over a set of standard 243's or not.
I had already pulled the trigger on mine when I found out all this but I do like the idea of lighter valves with the quite aggressive cam I have.

 

thank you Y2K i think i heard the 243s was ls6 ,but yes your right if i want to stay in the budget then standard rokers an the 243 remanned heads seems to be right for me an timeing chain type kit with springs an cam would fit too. spring seems to be getting hear finaly enjoy

 

On the timing chain, double rollers I have read will not fit under the stock timing cover so be careful when you shop. I used a high quality single chain, the Katech C5-R (Corvette racers use these a lot) and a new set of GM performance sprockets. Super strong and less drag so more hp than a double chain and no fitment issues.