241 heads vs 243 heads
01-21-2009, 09:10 PM
#41
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The only way to know for sure is to take a few valves out and have a look for your self. Since the seats were replaced for the larger valves, you must have had a valve job done. Check the quality of work where the machine cutting meets the uncut casting. If they have already been blended or make a reasonably smooth transition, you will likely be fine. If not, you have room for improvement with some careful bowl work.
In all the posts I have seen here, the biggest improvements to stock castings comes from a quality valve job and porting the areas around the seat and the guides.
In all the posts I have seen here, the biggest improvements to stock castings comes from a quality valve job and porting the areas around the seat and the guides.
01-26-2009, 12:52 AM
#43
In ported form AND stock form the 243's are superior. They have a better shape and more meat in the right areas. No doubt you can improve the 241's with porting, and a well ported set of 241's will do better than a pair of poorly ported 243's. There are areas in 241's where a good porter would need to remove material to get the perfect shape he wanted, but he can't because he'd hit water.
10-27-2009, 06:15 PM
#44
im not goin to try and steal any ones glory here but i have to agree with hammertime with the numbers and the streetablity vs. raceability. even tho your 241 heads may flow 320 cfm on the intake, the only time any engine is going to use that full 320 cfm is if it is forced in there. but then yoour exhuast is 100 cfm less then the intake which means if youo do use all your 320 cfm then your going to be backed up on the exhaust side but thats besides the point. for a moderately sized cam you do want a good flowing intake and a good flowing head but not to the point where the head is only good at max rpms. you want a head that can flow decently at driving speeds and rpms, cuz honestly where are you going to use over 250 cfm wide open daily unless the car is a dedicated race car. thats why the l92 heads are a great flowing head but those heads are almost never going to meet their full potential. but not only do you want flow rating at low rpms, but it also comes down to volume vs. effeciency like hammertime said. if you have to much volume and too little effeciency then the flow will slow down to the point where the heads are a race only application even with an aggressive street cam. so want a head that can both provide enough air for the cam you have chosen but also provide enough flow that it can be driven at streetable speeds and rpms. so yes 241's and 853's stock are very restrictive for even the mild cam swap. but a good set of ported 241's or 853's are better then stock 243's and will be enough for the mild to moderate cam swap (220 to high 230 duration cams), but anything over that will deffinately want a set of ported 243's or a set of cnc'd heads. but once again it also depends on the flow ratings not only at maximum valve lift but at all through the lift cycle.
10-27-2009, 09:35 PM
#46
Oh yea, we're in a 9 month old thread
10-01-2010, 02:26 PM
#48
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My 2000 has 853 cast.. I can pick up a set of assembled 241's from a guy down the road for 125 (used, off a 2001 SS). Would it be worth it to get them ported, and improve the valve springs and then throw them on when I eventually decide on a cam?
I just wanna know how much more power I could potentially get out of the 241s vs. my 853s. And the big plus is I wouldn't have to have my car torn apart while the heads are getting ported/ i'm saving for the cam and valve train parts?
I just wanna know how much more power I could potentially get out of the 241s vs. my 853s. And the big plus is I wouldn't have to have my car torn apart while the heads are getting ported/ i'm saving for the cam and valve train parts?
10-01-2010, 02:33 PM
#49
My 2000 has 853 cast.. I can pick up a set of assembled 241's from a guy down the road for 125 (used, off a 2001 SS). Would it be worth it to get them ported, and improve the valve springs and then throw them on when I eventually decide on a cam?
I just wanna know how much more power I could potentially get out of the 241s vs. my 853s. And the big plus is I wouldn't have to have my car torn apart while the heads are getting ported/ i'm saving for the cam and valve train parts?
I just wanna know how much more power I could potentially get out of the 241s vs. my 853s. And the big plus is I wouldn't have to have my car torn apart while the heads are getting ported/ i'm saving for the cam and valve train parts?
save up more and get a set of TSP ported 243 castings. instead of buying and having the 241 heads worked on.
10-01-2010, 09:04 PM
#51
tsp stage 1 243's typically gain 45-50whp. 241's ported by Ai usually net 30-35whp... a budget set of ported 241's should net 20-25whp. The tsp heads are 11-1200.00 range. your lookin at spending 525 on 241's, but your only getting half the gains of the stage 1 243... Im with NemeSS, save your money for something better.
Last edited by kinglt-1; 10-01-2010 at 09:14 PM.
10-01-2010, 11:21 PM
#54
i would just buy 243 heads and leave them unported and get a valve job and possible mill them. There is plenty of power to be had with just that and could port later down the road or sell them and get better heads. 243s are alot easier to sell than 241s
10-01-2010, 11:54 PM
#56
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I bought a set of stock 02' Z06 243's with the valve springs for $400 locally off of CL and I plan on getting rid of the springs to match the cam I eventually choose with the right springs. IMO if you are looking to gain an extra couple tenths at the track then yes get them worked. But if it's gonna be a street car that's got a set of nads, there's other places you can spend money and make it count.
The 243's flow just as well as 317's so if you are gonna buy a set of heads for a street/strip car, then don't even bother buying a set of 243's if you are going to get them worked on. Buy a cheap set of 5.3 heads and get them milled and ported. You can throw a rock out your window and hit 5 of the damn things.
The 243's flow just as well as 317's so if you are gonna buy a set of heads for a street/strip car, then don't even bother buying a set of 243's if you are going to get them worked on. Buy a cheap set of 5.3 heads and get them milled and ported. You can throw a rock out your window and hit 5 of the damn things.
10-02-2010, 12:33 AM
#58
I have some non ported 799's on my car. I wasnt even looking for heads, but came across them locally on Craigslist. Picked them up for $200, had them checked out, and bolted them up with cam swap. No numbers yet, tune will come this spring. Hoping for at least 400 rwhp N/A. Any numbers from yours?
Looks like they might be taking a trip.