LS3 with 243 Heands and Nitrous
02-17-2019, 07:51 PM
#1
LS3 with 243 Heads and Nitrous Building a LS3 with 243 heads. 243’s have 660’s dual valve springs and a valve job. Running a Texas Speed Torquer V4 Cam 231/234 629/615 112 LSA. Pistons are -2cc CP Forged Pistons. Texas Speed Super H Beam Rods. The crank is stock other than being balanced and polished. Nitrous is a plate kit from NX going to spray 200-250. Intake is a LS1 with a stock 78mm throttle body. The motor should be around 11.1 compression. Anyone have HP and Torque numbers from something similar. Thanks Michael
Last edited by Novakane1963; 02-17-2019 at 08:46 PM.
02-17-2019, 09:05 PM
#2
LS3 with 243 Heands and Nitrous Building a LS3 with 243 heads. 243’s have 660’s dual valve springs and a valve job. Running a Texas Speed Torquer V4 Cam 231/234 629/615 112 LSA. Pistons are -2cc CP Forged Pistons. Texas Speed Super H Beam Rods. The crank is stock other than being balanced and polished. Nitrous is a plate kit from NX going to spray 200-250. Intake is a LS1 with a stock 78mm throttle body. The motor should be around 11.1 compression. Anyone have HP and Torque numbers from something similar. Thanks Michael
02-18-2019, 10:40 AM
#7
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02-19-2019, 09:21 AM
#8
Hey 🍆 head! I didn’t ask for your opinion of why I did what I did I simply asked about HP not how you would build it!
02-19-2019, 05:46 PM
#9
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Building a LS3 with 243 heads. 243’s have 660’s dual valve springs and a valve job. Running a Texas Speed Torquer V4 Cam 231/234 629/615 112 LSA. Pistons are -2cc CP Forged Pistons. Texas Speed Super H Beam Rods. The crank is stock other than being balanced and polished. Nitrous is a plate kit from NX going to spray 200-250. Intake is a LS1 with a stock 78mm throttle body. The motor should be around 11.1 compression. Anyone have HP and Torque numbers from something similar. Thanks Michael
02-19-2019, 07:30 PM
#10
[QUOTE=01CamaroSSTx;20050753]Running 243's designed for a 4" bore on a 4.065 bore will work but you are restricting the engines ability to take in a big breath of air and fuel. You can make more power and torque with cylinder heads designed for that larger bore. If it where me I'd hunt for a set of LS3's and run an adapter plate to keep your cathedral stuff and run an adapter plat to switch over to a larger 4 bolt throttle body that is much larger than 78mm and that will let you use the cathedral intake. That would really help it out a bunch but to answer your question hypothetically as I'm not expert maybe 400 fwhp.[/QUOTE
Thanks for the information and I’m in the process of looking for some LS3 heads.
Thanks for the information and I’m in the process of looking for some LS3 heads.
02-19-2019, 08:47 PM
#11
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02-21-2019, 01:47 PM
#13
This build would be much better with ported 243's by AI, TEA, FED, etc if you wanted to keep stock casting and run a TBSS style 4 bolt intake to let it breathe.. That's what I've considered for my 96 c1500 build but I might just opt for ls3 top end. John Bewley told me on FB that a 6.2 with stock 243's (don't remember which intake) would make 430/430. And even that is choking the 6.2.
02-21-2019, 03:43 PM
#14
Building a LS3 with 243 heads. 243’s have 660’s dual valve springs and a valve job. Running a Texas Speed Torquer V4 Cam 231/234 629/615 112 LSA. Pistons are -2cc CP Forged Pistons. Texas Speed Super H Beam Rods. The crank is stock other than being balanced and polished. Nitrous is a plate kit from NX going to spray 200-250. Intake is a LS1 with a stock 78mm throttle body. The motor should be around 11.1 compression. Anyone have HP and Torque numbers from something similar. Thanks Michael
Think about it, Its very close to a cammed LS2 6.0 and they are typically in the 430 NA range.
02-21-2019, 04:29 PM
#15
I don't think it's worth it unless you can afford a set of cathedrals that can let it breathe. If not you essentially overpaid for what a 6.0 could do. Leaving too much on the table with the stock cathedrals. I think most "stage 2" CNC programs would work well, but for the price of new valves and everything it might work better to hop onto a set of 220's. Or just stick with the ls3's and get a cam matched for your goals
02-21-2019, 05:20 PM
#16
I don't think it's worth it unless you can afford a set of cathedrals that can let it breathe. If not you essentially overpaid for what a 6.0 could do. Leaving too much on the table with the stock cathedrals. I think most "stage 2" CNC programs would work well, but for the price of new valves and everything it might work better to hop onto a set of 220's. Or just stick with the ls3's and get a cam matched for your goals
02-21-2019, 05:58 PM
#18
TECH Senior Member
02-21-2019, 06:00 PM
#19
02-21-2019, 06:07 PM
#20
TECH Senior Member
Usually even a bit more. Cam Motion on their mild cams uses a 10-degree split. Their Titan series higher performance cams use an 8-degree split on the 2 mildest cams, the next hotter one uses 10 degrees, and the hottest (232/244) is 12 degrees. So there ya go.