usnfenix

iTrader: (11)

hey everyone, picked up a 2000 firehawk for my third f-body. car came to me stock with 90k miles with only mods being lid, long tubes and slp catback. ive already done bellows ( only because i got it for free) and SSRA, along with LCA relocation brackets and LCAs. ive got a friend who has a set of 243's laying around, would it be worth it to me to put the 243's on with the rockers and springs they came with and get rid of my 853 heads? ls6 intake is planned at some point but for now would i see a decent power gain going to 243's? i would be taking it to efi alchemy for a professional dynotune afterwards. it sounds as it is like their may be a lifter ticking or something, but could be piston slap. only hear it on cold engine and im ok with replacing some valvetrain parts for peace of mind.

WS6ICK2k

Yea for sure stock unported 243s make more power than the 853s. They have smaller combustion chambers for a bump in compression. The only thing you may need to change/check by measuring would be the push rod length because it could change valve train geometry slightly. It would also be a good time to check the valvetrain componets that could be making the noise. I suggest posting a idle clip on here and let some of the experts comment on here. The LS6 243s unported are slightly smoother due to differences in the casting process I believe they come out of a sand mold which leads to smoother ports, less imperfections. Ported 243-->853/241 stockers = 55-65RWHP
I would estimate unported 243s for get you maybe 20-25 + RWHP. There is a few builds on here with a decent cam and stock untouched 243s laying down around 400-420 RWHP depending on cam + supporting mods.