243 vs ls3
i no flow numbers arent everything but my tea 243 flow more with 3.90 bore than stock ls3 does with 4.065 so i was thinking put the 243 on a 4.065 bore and flow numbers should increase and by the 243 heads being a smaller runner the air speed should be quicker and more torque and better throttle response.what do yall think
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Joined: Aug 2009
Posts: 1,841
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From: Coast of San Mateo County Between Pacifica & HMB
Sbf
You answered your own questions, well ported 243s will perform
Much better on the street than stock LS3s with the following
Qualifiers: less than 400 CI, up to 3.73:1 Gears, small to
Medium size cams ~ 226-236 intake durations. Well ported cathedrals
Only need +~4-6 degree exhaust split to ~6500 RPM.
Stock LS3s need AT LEAST +8-12 degrees split to ~6500 RPM because the
Exhaust flows so poor (~60% vs ~70% for cathedrals)
you would probably start with 6-8 fewer degrees of intake duration with
Square ports in order to keep some throttle response.
My .02
You answered your own questions, well ported 243s will perform
Much better on the street than stock LS3s with the following
Qualifiers: less than 400 CI, up to 3.73:1 Gears, small to
Medium size cams ~ 226-236 intake durations. Well ported cathedrals
Only need +~4-6 degree exhaust split to ~6500 RPM.
Stock LS3s need AT LEAST +8-12 degrees split to ~6500 RPM because the
Exhaust flows so poor (~60% vs ~70% for cathedrals)
you would probably start with 6-8 fewer degrees of intake duration with
Square ports in order to keep some throttle response.
My .02
If you're looking at a quality set of ported 243's vs. unported LS3/L92 heads, I'd go ported 243's. The LS3 intake runners are much larger and don't carry the port velocity that the cathedral runners do, which you will notice on a stock stroke application. The stock, unported LS3 heads flow right at 300 cfm on our flow bench. You can see the flow data for the Precision Race Components stage 2.5 LS6 cylinder heads below:
http://www.texas-speed.com/p-1172-pr...-castings.aspx
The price listed is if you send your castings to us for porting. Let us know if we can help you out!
http://www.texas-speed.com/p-1172-pr...-castings.aspx
The price listed is if you send your castings to us for porting. Let us know if we can help you out!
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Largest Stocking Distributor of LS-x Engines / CHECK OUT OUR NEW WEBSITE!
COMP - FAST - PACESETTER - DIAMOND RACING - EAGLE SPECIALTY PRODUCTS - CALLIES - COMETIC GASKETS
RAM CLUTCHES - MOSER ENGINEERING - KOOK'S HEADERS - ARP - GM BOLTS AND GASKETS - MSD - NGK
POWERBOND - ASP - AND MORE!
i think he is in the ball park.its a few threads on here with a ls1 5.7 tea 243s eps 234/242 fast 102 hit 500rwhp the manual so i would say he is in there
thanks guys i was thinking the 243s would be better but sometimes its better to hear other opinions.i think im gonna just put my tea 243s on a ls3 377 with a super vic 4150 tb.it should run well in my 71 nova


