What are the differences? I know 243s came stock on the z06's and gto's. LS6 heads right? How do they give ls1's more power. Versus porting your stock 241 heads? Just a nebie trying to learn a thing or two.

 

You are correct as they are ls6 heads. They came on the zo6 and ls2 engines. The reason they give more power is because they have larger intake and exhaust ports that create better flow, increasing power. The valves are also a little larger but not much, but helps with flow. Im sure others can chime in here for anything else that may be different. A good port job on ls1 heads will cost you what 243 heads will and will flow about that same and give you very similar results in gains.

 

From the stickies up above that should be read. Differences in stock heads.
https://ls1tech.com/forums/1740922-post41.html

And a quick simple search turns up this. There are quite literally hundreds more of these threads.
https://ls1tech.com/forums/generatio...243-heads.html
https://ls1tech.com/forums/generatio...241-243-a.html
https://ls1tech.com/forums/generatio...-vs-243-a.html
https://ls1tech.com/forums/generatio...-vs-243-a.html

And a good page on all the tech specs on stock parts.
http://www.smokemup.com/tech/ls1.php


The short answer is that they will give you about 20-30 more rwhp than the 853/241 castings. This is accomplished by having larger port volumes and a smaller combustion chamber.

A decent port job will bring 241/853 castings into the neighborhood of stock 243s and some high end porting can allow them to be better. However getting the same port work on 243s will still have them surpassing the 241/853s.

 

241/853/243/317/373 heads all had the same sized valves. 2.00" intake and 1.55" exhaust in stock format. The only real difference is if you can get authentic z06 heads they had hollow intake valve stems and hollow sodium filled exhaust valve stems making them lighter.

 

Sweet guys thanks for the input!

 

I was told by a reputable speed shop here in Htown that ported 243's produce up to 20% better flow numbers than ported 241's. I'd love 243's but really thinking about saving a few bucks and porting my 241's and put money somewhere else, especially since I already have them on car and one less thing to shop/trade for.

 

i hope your got more info because yr so far off 241 head done rite will kill a stock 243 head lol try again !!!!!!

 

I put down 381 thru an A4 with an LS6 long block and supporting mods. The package pulls hard for a now dated stock setup!!

 

Mine has "sleeper" 241's.... (bottom # N/A - top # w/a little juice)

 

English much??