241 Heads and 243 Heads
241's came on late '00 -'02 F-bodies, late '00 to 2004 C5's
243's came on '01-'04 C5 Z06's, and all GTO's as I recall [LS1 and LS2]
the 243 head is better flowing than the 241 and with the right porter, right cam, and right tuning can make a **** ton of power.
I have CARTEK 4X 243's making 507RW with supporting mods, through 4.56 gears in a 12-bolt. track times in Sig.
The 243 head is still a good head. Even un-ported it shows big improvements over the 241/853 heads that came stock on F-Bodies.
243's came on '01-'04 C5 Z06's, and all GTO's as I recall [LS1 and LS2]
the 243 head is better flowing than the 241 and with the right porter, right cam, and right tuning can make a **** ton of power.
I have CARTEK 4X 243's making 507RW with supporting mods, through 4.56 gears in a 12-bolt. track times in Sig.
The 243 head is still a good head. Even un-ported it shows big improvements over the 241/853 heads that came stock on F-Bodies.
yeah, I forgot alot of things while working on it, so I'd have to go back and re-do somethings or double check them. But well worth the time. I've been stock piling parts for months. Bought 2 cams before I started the build, I had a custom cam but I wasnt happy with the size so I upped it. Yeah I had a LS6 intake I sold it then got layed off from work so I had to put my stock ls1 back on. But Im waiting to get my last check and maybe pickup a fast this weekend. I might be able to help ya get an LS6 intake.
LS6 oilpump, hardend Pushrods, I would go with patriot Extreme valve springs, LS7 or CTS-V lifters, I got an underdrive pulley but thats optional. If u did get the MS4, its very important NOT to mill the heads.
Its most common if a head gets over heated you can mill them, basically resurfacing them where they bolt to the block. Yeah it raises your compression, but with the MS4 you have to watch your piston to valve clearances. The last thing you want is ur piston saying hello to your valves.
If u did get the 243's Id leave em stock with the MS4. You will love the sound and responce, not to mention torque.
If u did get the 243's Id leave em stock with the MS4. You will love the sound and responce, not to mention torque.
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Verdad Gallardo You should be just fine with the stock heads, and using Patriot Extreme valve springs. I have Dual gold springs, but the ms3 is a lot smaller lift than the ms4. The extreme springs are good to 660lbs I beleive maybe 670, cant remember, dual gold springs are rated to support 650 lbs of lift.
241's came on late '00 -'02 F-bodies, late '00 to 2004 C5's
243's came on '01-'04 C5 Z06's, and all GTO's as I recall [LS1 and LS2]
the 243 head is better flowing than the 241 and with the right porter, right cam, and right tuning can make a **** ton of power.
I have CARTEK 4X 243's making 507RW with supporting mods, through 4.56 gears in a 12-bolt. track times in Sig.
The 243 head is still a good head. Even un-ported it shows big improvements over the 241/853 heads that came stock on F-Bodies.
243's came on '01-'04 C5 Z06's, and all GTO's as I recall [LS1 and LS2]
the 243 head is better flowing than the 241 and with the right porter, right cam, and right tuning can make a **** ton of power.
I have CARTEK 4X 243's making 507RW with supporting mods, through 4.56 gears in a 12-bolt. track times in Sig.
The 243 head is still a good head. Even un-ported it shows big improvements over the 241/853 heads that came stock on F-Bodies.
Just do ur research and call around. I called Jon at Tx speed and Thunder Racing so many times comparing and getting idea's. I guess most of the problem is Im very picky. Hell I'm already planning and researching my 408 build. Now its just coming up with the money, and I still cant decide if Im gonna go with the 408 or 427. 
Thread Starter
TECH Enthusiast
Joined: Jun 2009
Posts: 501
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From: Birmingham, Alabama
Just do ur research and call around. I called Jon at Tx speed and Thunder Racing so many times comparing and getting idea's. I guess most of the problem is Im very picky. Hell I'm already planning and researching my 408 build. Now its just coming up with the money, and I still cant decide if Im gonna go with the 408 or 427.
Im looking for a super quick street car lol
The club Im in, we go once amonth for a battle of the car clubs event. I havent been this month. Im hoping to go soon though, although I gotta get a tune first. Being an auto, I would check into a like a build 4l80e, its alittle stonger and 4l60. Get a great stall, i like yank and Vig. Build up your 10 bolt they can handle alot if u build em right. Stick with the 346, and just build the hell outta ur top end. I dont like Nitrous, but most of my friends wont run without it. Ohh yeah and gears. Auto I'd run 4.56's, thats me though.
I cant recall how much ive spent on my car since i bought it. But the HCI I have around 1800, 800 in suspension, 500 in rear end. Id like to get injectors too. but thats later.