View Poll Results: Which one would be the best street/strip car?
Iron 370 with L92 heads and L76 car intake
14
12.84%
Iron 370 with ported 243s and FAST 90/90
9
8.26%
Aluminum 383 with ported 243s and FAST 90/90
86
78.90%
Voters: 109. You may not vote on this poll
370 vs 383
08-03-2007, 12:14 AM
#1
370 vs 383 My friends and I were discussing this earlier today. Which way would you go, and why?
Car: LS1 F-body, full weight, 9"
NA build
Please vote and discuss. Personally I don't think the 370 will make the extra power to benefit from the extra cubes. But I could very well be wrong.
Car: LS1 F-body, full weight, 9"
NA build
Please vote and discuss. Personally I don't think the 370 will make the extra power to benefit from the extra cubes. But I could very well be wrong.
08-03-2007, 12:47 AM
#3
But enough to make up for the weight?
And remember, the 370 is less cubes on a short stroke with an intake that won't make power up high where the short stroke, big bore would normally shine with a better intake.
I'm not trying to sway people either way. I'm just trying to point out the factors in that one.
And remember, the 370 is less cubes on a short stroke with an intake that won't make power up high where the short stroke, big bore would normally shine with a better intake.
I'm not trying to sway people either way. I'm just trying to point out the factors in that one.
08-03-2007, 01:23 AM
#4
I would go with 383ci and ported 243's. Reason being is that for a street/strip car, more ci is always a plus. That and the longer stroke will make power in a lower RPM and help preserve parts. The 243's have enough in em to feed 427ci and propel f-bodies into the low 9's when done properly. L92's seem more suited for larger motors, or higher RPM screamers. Now if you epoxied the L92's and reshaped the ports, thats another story...
08-03-2007, 02:29 AM
#7
Yeah i noticed that when i read your post. Didnt know they had this issue. When i was looking at L92/L76 combos they were still barely available (intake was actually not even available yet when i was shopping) and no one really knew what they could do. I ended up going with some stock 317 heads for my procharged application since they are a cheap proven option. Have yu heard anything about the L76 intake with forced induction?
Does anyone offer a carb style intake that will bolt to teh L92? If they do throw one of those on with an elbow and throttle body, then procede to rev it to stupid power with a lumpy cam.
Does anyone offer a carb style intake that will bolt to teh L92? If they do throw one of those on with an elbow and throttle body, then procede to rev it to stupid power with a lumpy cam.
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08-03-2007, 04:31 AM
#8
TECH Senior Member
I use a 370 with nitrous into the low 10s, kissing high 9's on bigger shots.
The reason I didn't go 383 was the cost of the crank. basicaly it would cost the same for a 383 or 408 (+/-), 370 was more economical.
It revs high and can stand big shot abuse. 92lbs extra over my previous stock cubes.
The reason I didn't go 383 was the cost of the crank. basicaly it would cost the same for a 383 or 408 (+/-), 370 was more economical.
It revs high and can stand big shot abuse. 92lbs extra over my previous stock cubes.
08-03-2007, 11:26 AM
#11
Originally Posted by N4cer
Cost aside. We were just discussing which one we'd use and why. I said street driven and wants the most street *****. 408 not an option. This was 383 vs 370.
but my vote is 370 with l92 or ls6 heads,
i would just go for a vic with elbow for intake and 90mm tb.
08-03-2007, 11:47 AM
#12
Originally Posted by N4cer
Whoa you forget: the L76 car intake is limited and dictates revs to be worthless above 6300. It falls off.
For example, you can rev to 7k and make peak power at 6700 pretty easily with a big enough cam in a 346. Stick the FAST 90 on a 427 and it'll struggle to peak past 6200. Now, the natural affinity for the FAST is to peak ~ 6300, but you can overcam it and get the peak up if the engine is small enough to be filled at the upper ranges.
The same thing applies to the L76. If you look at the cam only LS3s, they are making comparable power to a 408 with the same intake, just at a higher RPM. They are approx 370cid as well, the only difference is they have a bit more bore to work with to unshround the valves of the L92s.
Further, the 3.905" bore of the 383 is really going to hurt it. If you go with some big time flowing 3.9" bore heads, you still aren't going to hit the power that a head designed for a 4"+ bore can hit. The peak numbers may be similar, but the midrange numbers are going to suffer. With a plastic intake (L76 or FAST) you need to maximize mid-lift flow.
I can see a hydraulic cammed 383 doing 505-520 at max. I could see the 370 doing that too, but with less cam.
I have a 383, and if you build it right, it can make power. However, given the choices, I'd be willing to give the 370 a chance with the L76/L92 stuff. If you had TFS or AFR heads for the 383, I might swing that way.
08-03-2007, 11:58 AM
#13
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Originally Posted by JakeFusion™
The L76 limits it in big cube applications. But 370cid is much smaller and takes less air to fill at a given RPM. So if a 402/416 is limited to about 6300, you can cam effectively to overcome that. Just like with a FAST 90.
For example, you can rev to 7k and make peak power at 6700 pretty easily with a big enough cam in a 346. Stick the FAST 90 on a 427 and it'll struggle to peak past 6200. Now, the natural affinity for the FAST is to peak ~ 6300, but you can overcam it and get the peak up if the engine is small enough to be filled at the upper ranges.
The same thing applies to the L76. If you look at the cam only LS3s, they are making comparable power to a 408 with the same intake, just at a higher RPM. They are approx 370cid as well, the only difference is they have a bit more bore to work with to unshround the valves of the L92s.
Further, the 3.905" bore of the 383 is really going to hurt it. If you go with some big time flowing 3.9" bore heads, you still aren't going to hit the power that a head designed for a 4"+ bore can hit. The peak numbers may be similar, but the midrange numbers are going to suffer. With a plastic intake (L76 or FAST) you need to maximize mid-lift flow.
I can see a hydraulic cammed 383 doing 505-520 at max. I could see the 370 doing that too, but with less cam.
I have a 383, and if you build it right, it can make power. However, given the choices, I'd be willing to give the 370 a chance with the L76/L92 stuff. If you had TFS or AFR heads for the 383, I might swing that way.
For example, you can rev to 7k and make peak power at 6700 pretty easily with a big enough cam in a 346. Stick the FAST 90 on a 427 and it'll struggle to peak past 6200. Now, the natural affinity for the FAST is to peak ~ 6300, but you can overcam it and get the peak up if the engine is small enough to be filled at the upper ranges.
The same thing applies to the L76. If you look at the cam only LS3s, they are making comparable power to a 408 with the same intake, just at a higher RPM. They are approx 370cid as well, the only difference is they have a bit more bore to work with to unshround the valves of the L92s.
Further, the 3.905" bore of the 383 is really going to hurt it. If you go with some big time flowing 3.9" bore heads, you still aren't going to hit the power that a head designed for a 4"+ bore can hit. The peak numbers may be similar, but the midrange numbers are going to suffer. With a plastic intake (L76 or FAST) you need to maximize mid-lift flow.
I can see a hydraulic cammed 383 doing 505-520 at max. I could see the 370 doing that too, but with less cam.
I have a 383, and if you build it right, it can make power. However, given the choices, I'd be willing to give the 370 a chance with the L76/L92 stuff. If you had TFS or AFR heads for the 383, I might swing that way.
I see what you're saying about the 370/L92 setup BUT at the end of the day which one (383 small runner head vs 370/L92) would make more power under the curve, carry the peak well AND be much more streetable using a decent sized cam? I realize the L92 setup isnt going to need as big of a cam but the 383 REALLY *shouldnt* either.
Edit- I guess I should have laid out an example:
383 AFR 205, 234/242 112+2, ported FAST 90/90 1 3/4 headers, duals 11.5:1
370 L92/L76 (obviously a much larger runner head with MUCH larger valves than the AFR), 234/242 115+3, Ported L76/TB, 1 3/4 stepped to 1 7/8 headers and duals. 11.5:1
Last edited by lilbuddy1587; 08-03-2007 at 12:08 PM.
08-03-2007, 01:32 PM
#14
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I voted for the aluminum 383, im still debating whether im gonna go IRON 383 or get the 6.0L block and go bigger, i dont wanna go aluminum, dont care about how much lighter the block is. Iron 383 as in 5.3 block bored to 3.91 x 4.000 stroke with 6.125 rods.
08-03-2007, 02:20 PM
#16
My point is that 2 locals with ported stock heads, both had forged motors with the Trex. One - 347ci - made way better and more power than the 370ci. I know, one example. But it has me saying "Less cubes, more weight, shorter stroke:bore ratio so less low end grunt".
08-03-2007, 03:12 PM
#19
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If I hear another person say anything about weight im going to 
I have a bare alum block and a bare lq9 block in the garage right now, the iron block is probablly 40lbs heavier. The rotating assemblys way the same so that doesnt matter. If your wanting to go high horse power why wouldnt you run a tougher block. If weight is that big of an issue, then gut the interior, run lexan windows, then take the a/c, radio, and dash out of the car! If you are running an all out race car then maybe.
If your going to spend the $$ on a 4" stroke crank, why not spend an extra $300-$350 on the 6.0 block and make a 408? Pistons and rods are the same price either way. If not...just go 370. Only my $ .02, Ive built a couple of 408's so I know what they cost.
I have a bare alum block and a bare lq9 block in the garage right now, the iron block is probablly 40lbs heavier. The rotating assemblys way the same so that doesnt matter. If your wanting to go high horse power why wouldnt you run a tougher block. If weight is that big of an issue, then gut the interior, run lexan windows, then take the a/c, radio, and dash out of the car! If you are running an all out race car then maybe.
If your going to spend the $$ on a 4" stroke crank, why not spend an extra $300-$350 on the 6.0 block and make a 408? Pistons and rods are the same price either way. If not...just go 370. Only my $ .02, Ive built a couple of 408's so I know what they cost.
08-03-2007, 03:28 PM
#20
Yeah, you missed the point of simply which makes the power and is a better option without the cost factored in. And for a tougher block, I'm not aware of aluminum having any issues at high HP. Just people CLAIMING that it has issues. Got proof? I've not seen any.
We all agree on the 408, but that's not what the conversation is about.
We all agree on the 408, but that's not what the conversation is about.