Buying 243 used heads
Buying 243 used heads I need to know what to look when buying used 243 heads, I'm a rookie when it comes down to looking at heads. Any good info. would be awesome.
First make sure that "243" is actually casted in the head on top.. I would try and find some from an early Z06 Corvette. They had hollow intake valves and sodium filled exhaust valves. After purchasing some I would take them to a machine shop for a refresh and milling to ensure a good seal.
also not all the 243 vette heads have the hollow valves, just the Z06 came with them. so if the heads aren't off a Z06 they have the heavier valves
No its absolutley worth it. getting a set from an 02-04 z06 just gives you better valves that are a little lighter and better suited for high rpm use. The heads themselves flow better than any stock ls1 head and are usually good for an extra 20-25hp over a stock ls1 head so for the money its a pretty good mod as long as you have your old heads off anyway
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I think the whole ZO6 243 only thing is over rated. Hollow valves are lighter; but plenty of power has been made from LS2's and other solid stem valves. That depends a lot on the end use and rpm. Keep in mind that the pressure test is not a bad idea; but will not show all defects. A crack or flaw in the non coolant containing areas will not show up. Flatness check is also something to consider. If the heads need milled they need milled; but if they don't, don't do it. I am going to be putting a couple of sets up in the next week that might interest you if the ones you are looking at don't meet your needs. One set is bone stock LS2 and the other is TSP CNC ported. Sorry for the shameless plug.
Last edited by Mr.L88; Nov 27, 2011 at 04:23 PM. Reason: forgot item
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The 243/799 are used in everything from 4.8 trucks to ls2 6.0 c6 and gto. Only the 5.7 ls1 z06 got to use the hollow sodium filled valves.
I personally would have the heads checked and milled before install on my own motor and even more so if it's for a customer.
I personally would have the heads checked and milled before install on my own motor and even more so if it's for a customer.
I think the whole ZO6 243 only thing is over rated. Hollow valves are lighter; but plenty of power has been made from LS2's and other solid stem valves. That depends a lot on the end use and rpm. Keep in mind that the pressure test is not a bad idea; but will not show all defects. A crack or flaw in the non coolant containing areas will not show up. Flatness check is also something to consider. If the heads need milled they need milled; but if they don't, don't do it. I am going to be putting a couple of sets up in the next week that might interest you if the ones you are looking at don't meet your needs. One set is bone stock LS2 and the other is TSP CNC ported. Sorry for the shameless plug.
My point was for the guy not to skip out on a good deal just because the heads have solid stem valves. Hollow stem would be nice to have; but I would rather have a set of low hour LS2 heads with solid stems than a set of high hour LS6 with hollow. IF both were the same condition and shape I would choose hollow.
If there are valves breaking then there is not enough PTV or the valvetrain geometry is incorrect. A valve head doesn't just snap off because its tired. Plenty of solid valve have broke too.
when the ls6 were still under gm warranty I personally seen two at the local gm dealer that snapped on bone stock cars that gm was paying to fix I have also seen one ls7 do it so far if u do a search u will find that lost of people have had it happen on stock cars to each there own but I would not use them on my own engine that is why I bought ls2 heads and not ls6
