Can a 370 outperform a 383?
12-10-2008, 10:57 PM
#102
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IMHO i have seen many more 370's rip the **** out of 383's. depending on the heads a l92 head would not fit the 383 but would fit the 370. also the engines would perform at different rpm. the 370 would make more top end power compared to the 383. the 383 would make more lower end tq. ask your builder at hke. the 370 has less rotating mass, because yes it does have a bigger piston, but thats aluminum. so it has less steel rotating on the crank which makes it lighter.
Those 370's just ripped the living **** out of them huh.A good 383 combo will make over 500 rwhp NA...not bad top end HP do you think?I am not going to start a debate here,but a well set up 370 & 383 will be a good race.
12-10-2008, 11:15 PM
#104
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And if your going to do that why build a 383?? If your going to be buying rods, pistons and crank and want more CIs than a 370 build a 408 it won't cost any more. Its just not practical to build a large bore 383.
12-10-2008, 11:28 PM
#105
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Yep, thanks for starting the thread. It has been both entertaining and informative. I think it has spun out of your control.
How about this for a cold prayer in hell to bring this thread back to focus.
How much flywheel horsepower will this combo pump out? I can back calculate and guesstimate on rear wheel horsepower and ET once I know the flywheel horsepower.
-Blueprinted 370 short block, all the work done by yours truly.
-TFS 220 heads. Stock TFS 220 heads come with 2.055"/1.570" vales but I'd like to look into LS3 vales if I can
-Stock LS2/LQ9 head gasket
-Close to 11:1 with flat top pistons, not sure which pistons yet, or if they'll need major valve reliefs, but ones that can handle nitrous from 150-200hp jetting
-Comp Cams XER273HR (273/279 @ .006, 224/230 @ 0.050, 0.581"/.0.588", 114 LSA 112 ICL)
-Stock rockers
-LS7 lifters
-Fast 90/90
All rolled into a 4L65E and 3195lb chassis. Think it'll hit 11's N/A?
12-10-2008, 11:43 PM
#106
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12-10-2008, 11:50 PM
#107
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I didn't realize that there were so many poorly set up 383's in Billings Mt. Those 370's just ripped the living **** out of them huh.A good 383 combo will make over 500 rwhp NA...not bad top end HP do you think?
I am not going to start a debate here,but a well set up 370 & 383 will be a good race.
Those 370's just ripped the living **** out of them huh.A good 383 combo will make over 500 rwhp NA...not bad top end HP do you think?I am not going to start a debate here,but a well set up 370 & 383 will be a good race.
12-11-2008, 12:11 AM
#108
FormerVendor
Hahahaha this thread is only half true. In general the bigger bore has more "potential" power but that absolutely does not mean it will have more power in reality. You can easily build a 383 that will beat a 370 for sure. We did one that made 665 at the wheels or so that went 147 in the 1/4 and low 9s and no one did that with a 370. Of course we could too if we wanted and there are better heads for the bigger bore stuff. I've done many many 500+hp 383s but the small bore heads that do it are more rare. I would do the bigger bore iron block AND the 4 inch crank but the 370 also works great too.
Also I know few people on these boards have really ported heads but some of your real live OEM LSx heads do actually flow MORE on the smaller bores. When you unshroud them on a larger bores they sometimes go turbulent much sooner and make less power. Someone familiar with the LS6 head can make them flow more on a bigger bore of course but they don't automatically always flow more on the bigger bore in reality just by popping them on. Thats probably why our LS6 heads at SAM went over 150+ mph so long ago when others were running barely in the high 13Xs.
The EMC contest with sometimes over a 100K prize has been dominated by smaller bore undersquare engines when it was an open contest so again bigger bores don't necessarily just equal more power especially at under 7000 rpm at all unless you consider all the hard core NHRA and IHRA engine builders that won are really just a bunch of fools.
I think the engines would be close to the same and more dependent on the actual parts used on the 370 vs. the 383 but the 383 if done right on a fast90 type deal that turns under 7k can easily beat the 370 or vice versa so it really just depends.
Also I know few people on these boards have really ported heads but some of your real live OEM LSx heads do actually flow MORE on the smaller bores. When you unshroud them on a larger bores they sometimes go turbulent much sooner and make less power. Someone familiar with the LS6 head can make them flow more on a bigger bore of course but they don't automatically always flow more on the bigger bore in reality just by popping them on. Thats probably why our LS6 heads at SAM went over 150+ mph so long ago when others were running barely in the high 13Xs.
The EMC contest with sometimes over a 100K prize has been dominated by smaller bore undersquare engines when it was an open contest so again bigger bores don't necessarily just equal more power especially at under 7000 rpm at all unless you consider all the hard core NHRA and IHRA engine builders that won are really just a bunch of fools.
I think the engines would be close to the same and more dependent on the actual parts used on the 370 vs. the 383 but the 383 if done right on a fast90 type deal that turns under 7k can easily beat the 370 or vice versa so it really just depends.
12-11-2008, 12:15 AM
#109
FormerVendor
Just good pistons and rings and heads and cam and etc. just like usual! You can make a good strong 500+ rwhp deal easily with good heads.
I can build the 370 short block myself, probably for a little less than Texas Speed, plus I really like doing my own machine work. The only bennefit of the Texas Speed 370 would be the 6.125" rods compared to stock 6.098" LQ4 rods that I would be stuck using since I'd re-use the LQ4 rotating assembly except with new pistons.
I'm more interested in hearing what parts would optimize a 370 long block, given an end goal in mind as I have provided in my previous post.
I'm more interested in hearing what parts would optimize a 370 long block, given an end goal in mind as I have provided in my previous post.
12-11-2008, 01:32 AM
#111
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Ya I kinda laughed at what he posted too. Just had to get the last word in, and now this will start another pissing match.
That image is funny, but some people who are parents to disabled kids might not think so. Please don't post that kind of stuff again. Thanks - ADMIN
That image is funny, but some people who are parents to disabled kids might not think so. Please don't post that kind of stuff again. Thanks - ADMIN
Last edited by Damian; 12-11-2008 at 03:39 PM.
12-11-2008, 05:38 AM
#112
Hahahaha this thread is only half true. In general the bigger bore has more "potential" power but that absolutely does not mean it will have more power in reality. You can easily build a 383 that will beat a 370 for sure. We did one that made 665 at the wheels or so that went 147 in the 1/4 and low 9s and no one did that with a 370. Of course we could too if we wanted and there are better heads for the bigger bore stuff. I've done many many 500+hp 383s but the small bore heads that do it are more rare. I would do the bigger bore iron block AND the 4 inch crank but the 370 also works great too.
Also I know few people on these boards have really ported heads but some of your real live OEM LSx heads do actually flow MORE on the smaller bores. When you unshroud them on a larger bores they sometimes go turbulent much sooner and make less power. Someone familiar with the LS6 head can make them flow more on a bigger bore of course but they don't automatically always flow more on the bigger bore in reality just by popping them on. Thats probably why our LS6 heads at SAM went over 150+ mph so long ago when others were running barely in the high 13Xs.
The EMC contest with sometimes over a 100K prize has been dominated by smaller bore undersquare engines when it was an open contest so again bigger bores don't necessarily just equal more power especially at under 7000 rpm at all unless you consider all the hard core NHRA and IHRA engine builders that won are really just a bunch of fools.
I think the engines would be close to the same and more dependent on the actual parts used on the 370 vs. the 383 but the 383 if done right on a fast90 type deal that turns under 7k can easily beat the 370 or vice versa so it really just depends.
Also I know few people on these boards have really ported heads but some of your real live OEM LSx heads do actually flow MORE on the smaller bores. When you unshroud them on a larger bores they sometimes go turbulent much sooner and make less power. Someone familiar with the LS6 head can make them flow more on a bigger bore of course but they don't automatically always flow more on the bigger bore in reality just by popping them on. Thats probably why our LS6 heads at SAM went over 150+ mph so long ago when others were running barely in the high 13Xs.
The EMC contest with sometimes over a 100K prize has been dominated by smaller bore undersquare engines when it was an open contest so again bigger bores don't necessarily just equal more power especially at under 7000 rpm at all unless you consider all the hard core NHRA and IHRA engine builders that won are really just a bunch of fools.
I think the engines would be close to the same and more dependent on the actual parts used on the 370 vs. the 383 but the 383 if done right on a fast90 type deal that turns under 7k can easily beat the 370 or vice versa so it really just depends.
12-11-2008, 09:44 AM
#113
Well I must say this is a very informative thread...and a very entertaining one too! LMAO at TXZ28LS1 on the previous page asking about all the numbers and such with that much time on the board and that many posts and his mods in sig:
2002 Z/28- advanced auto parts lid, autozone longtube headers/ory, napa auto "X" cam, oreilly ported & polished heads, tornado fuel saver TB, target true duals, costco 9" cowlhood, tinted with black tape, level 6 tranny built by sam's club, AAFES drag welds, AAFES drag radials, walmart rollback roller rockers,..
That sh*t had me rolling once I noticed it!
/hijack
2002 Z/28- advanced auto parts lid, autozone longtube headers/ory, napa auto "X" cam, oreilly ported & polished heads, tornado fuel saver TB, target true duals, costco 9" cowlhood, tinted with black tape, level 6 tranny built by sam's club, AAFES drag welds, AAFES drag radials, walmart rollback roller rockers,..
That sh*t had me rolling once I noticed it!
/hijack
dude, these are real mods...
12-11-2008, 11:15 AM
#114
What it all boils down to is bore versus stroke.
I'll take bigger bore over longer stroke any day. Why do you think the NHRA prostock guys build bigger bore shorter stroke 500 inch motors? Because bigger bore motors make more power.
What would be a better test would be 2 engines closer in size, one with the bigger bore, and one with the longer stroke. BOTH with heads that are optimized to each respective engine.
I think everyone knows which one would win that one.
I'll take bigger bore over longer stroke any day. Why do you think the NHRA prostock guys build bigger bore shorter stroke 500 inch motors? Because bigger bore motors make more power.
What would be a better test would be 2 engines closer in size, one with the bigger bore, and one with the longer stroke. BOTH with heads that are optimized to each respective engine.
I think everyone knows which one would win that one.
Last edited by edcmat-l1; 12-11-2008 at 11:38 AM.
12-11-2008, 12:04 PM
#115
This thread is informative, yet comical. It just goes to show that just because someone has "Sponsor" under their name, they might not know **** about engine building. Not mentioning any name here 
I owned the first all-bore 382ci LS1 ever built, and it would kick the crap out of the all-stroke 383ci engines of the same era. Bigger bore is always better than bigger stroke, due to head flow potential as stated.
I owned the first all-bore 382ci LS1 ever built, and it would kick the crap out of the all-stroke 383ci engines of the same era. Bigger bore is always better than bigger stroke, due to head flow potential as stated.
12-11-2008, 03:12 PM
#116
6600 rpm clutch dump of death Administrator
Originally Posted by racer7088
The engine doesn't know whether it has more bore or stroke. The heads and the intake ports are what makes power. They only "see" pressure drop. There is no difference between the two according to the heads except that the motor with more bore can "breathe" better due to either larger valves and ports or the same but less shrouded identical ports so the "bore" motor will ultimately make more power. As some of you other guys noted however the bore AND stroke motor will make even more than the other.
Originally Posted by racer7088
You are getting good advice from everyone. Go as big as you can for the money. Bore will alow more room for breathing and make more power overall and more stroke you can run the more power you can make on that bore and the lower in rpm as well which is great for a reliable street engine.
Originally Posted by SStrokerAce
Usually the most cubes you can get for the money is my recomendation. Most times that means getting the largest bore stock block that will hold the power (we are lucky in Chevyland that our stock blocks for the most part do) and putting the longest stroke crank in there that doesn't need special parts to fit, like small journal rods and small base circle cams.
If you are class restricted to a cube size then use the larger bore motor and spin the motor up to make more HP. Even if you have a RPM limit you get advantages out of this setup. Smaller bore setups have the advantage only when detonation plays into the situation, because they help the burn and prevent detonation.
The bore/stroke combo doesn't make more power/TQ in certain areas of the tq curve, that's just plain not true. The bore, stroke combination has a discplacement that is used to create a low pressure in the cylinder so that air/fuel mixture moves there from the high pressure port. The bore, stroke combo doesn't change where in the RPM range this happens.
Bret
If you are class restricted to a cube size then use the larger bore motor and spin the motor up to make more HP. Even if you have a RPM limit you get advantages out of this setup. Smaller bore setups have the advantage only when detonation plays into the situation, because they help the burn and prevent detonation.
The bore/stroke combo doesn't make more power/TQ in certain areas of the tq curve, that's just plain not true. The bore, stroke combination has a discplacement that is used to create a low pressure in the cylinder so that air/fuel mixture moves there from the high pressure port. The bore, stroke combo doesn't change where in the RPM range this happens.
Bret
So, the question comes down to what you have and what you have to spend. I'll definitely take the "biggest" motor I can get. But, it depends on what heads I have on hand, or if they are new purchases. If it was a "greenfield" scenario I think I would put my money into bore.
12-11-2008, 03:21 PM
#117
What it all boils down to is bore versus stroke.
I'll take bigger bore over longer stroke any day. Why do you think the NHRA prostock guys build bigger bore shorter stroke 500 inch motors? Because bigger bore motors make more power.
What would be a better test would be 2 engines closer in size, one with the bigger bore, and one with the longer stroke. BOTH with heads that are optimized to each respective engine.
I think everyone knows which one would win that one.
I'll take bigger bore over longer stroke any day. Why do you think the NHRA prostock guys build bigger bore shorter stroke 500 inch motors? Because bigger bore motors make more power.
What would be a better test would be 2 engines closer in size, one with the bigger bore, and one with the longer stroke. BOTH with heads that are optimized to each respective engine.
I think everyone knows which one would win that one.
