Stock 283 245 hp to 270 hp, what cam?
07-18-2006, 06:18 PM
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Melting Slicks
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Stock 283 245 hp to 270 hp, what cam?
I am putting the stock 2x4's on my 1957 this weekend. If I get a mind to, I may slip a cam in at the same time. I do not want to use the Duntov 097 cam, only because it loses max torque compared to stock and the powerband is too high up!
-----But it must be solid lifters, (for the sound of the lifters). I am thinking of a milder cam than the Duntov. Something about 208/214 on 112 lobe seperation, with about .425 lift or so. I want to still use the stock valve springs.
-----I would like the cam to be drivable from 1200 to 5500 rpm. Any burbley or lopey idle at 950 rpms is fine. Engine is bone stock 283 245 hp with factory dual fours. 3400 pound car, 4.11 rear, Tremec 5-speed with 2.88 1st gear. Street use only.
-----I have a nice mild cam in my 2001 Vette, specs in signature below, I really like that cam, want something similar for the 57. Anyone?
-----But it must be solid lifters, (for the sound of the lifters). I am thinking of a milder cam than the Duntov. Something about 208/214 on 112 lobe seperation, with about .425 lift or so. I want to still use the stock valve springs.
-----I would like the cam to be drivable from 1200 to 5500 rpm. Any burbley or lopey idle at 950 rpms is fine. Engine is bone stock 283 245 hp with factory dual fours. 3400 pound car, 4.11 rear, Tremec 5-speed with 2.88 1st gear. Street use only.
-----I have a nice mild cam in my 2001 Vette, specs in signature below, I really like that cam, want something similar for the 57. Anyone?
Last edited by CJS; 07-19-2006 at 08:25 AM.
07-18-2006, 06:59 PM
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Originally Posted by CJS
I am putting the stock 2x4's on my 1957 this weekend. If I get a mind to, I may slip a cam in at the same time. I do not want to use the Duntov 097 cam!
-----But it must be solid lifters, (for the sound of the lifters). I am thinking of a milder cam than the Duntov. Something about 208/214 on 112 lobe seperation, with about .425 lift or so. I want to still use the stock valve springs.
-----I would like the cam to be drivable from 1200 to 5500 rpm. Any burbley or lopey idle at 950 rpms is fine. Engine is bone stock 283 245 hp with factory dual fours. 3400 pound car, 4.11 rear, Tremec 5-speed with 2.88 1st gear. Street use only.
-----I have a nice mild cam in my 2001 Vette, specs in signature below, I really like that cam, want something similar for the 57. Anyone?
-----But it must be solid lifters, (for the sound of the lifters). I am thinking of a milder cam than the Duntov. Something about 208/214 on 112 lobe seperation, with about .425 lift or so. I want to still use the stock valve springs.
-----I would like the cam to be drivable from 1200 to 5500 rpm. Any burbley or lopey idle at 950 rpms is fine. Engine is bone stock 283 245 hp with factory dual fours. 3400 pound car, 4.11 rear, Tremec 5-speed with 2.88 1st gear. Street use only.
-----I have a nice mild cam in my 2001 Vette, specs in signature below, I really like that cam, want something similar for the 57. Anyone?
I don't believe a spec comparison between a roller cam and flat tappet cam is valid, # for #. But I am certainly no cam expert or even too knowledgable of the subject. I can tell you the 097 cam will work really well with the gears you have and your 283, even at low speed. But then, you said you didn't want one of them.
07-18-2006, 07:20 PM
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Why don't you want a 097? It has every single characteristic that you mention you want. The 097 is a VERY mild cam that has alot of low and mid range punch. Mine is in a 1960 with a bone stock 270HP, 4spd., and 4:11's. Throttle response at 2000RPM is incredible. Try one, you'll like it.
07-18-2006, 08:19 PM
#4
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Originally Posted by GO GIRL
...... The 097 is a VERY mild cam that has alot of low and mid range punch. Mine is in a 1960 with a bone stock 270HP, 4spd., and 4:11's. Throttle response at 2000RPM is incredible. Try one, you'll like it.
07-18-2006, 09:42 PM
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Well maybe the 097 Duntov is the way to go! I don't have anything against it for sure. Just figured there are better cams invented by now. I do 90% of my driving in the 1200 to 2000 rpm range and want a really good pull in that rpm range. Even at the expense of 5000 rpm and up power.
I realize that my LS1's cams numbers do not correlate to 283 cam numbers! I am just saying that it is a level of cam I like. It will pull out smoothly from 600 rpm at 45 mph in 6th gear going uphill. (helped by FI and computers of course too)!
I realize that my LS1's cams numbers do not correlate to 283 cam numbers! I am just saying that it is a level of cam I like. It will pull out smoothly from 600 rpm at 45 mph in 6th gear going uphill. (helped by FI and computers of course too)!
07-18-2006, 10:47 PM
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Originally Posted by CJS
I do 90% of my driving in the 1200 to 2000 rpm range and want a really good pull in that rpm range. Even at the expense of 5000 rpm and up power.
When properly adjusted, mechanical lifters should be virtually indistinguishable from hydraulics.
Lean out the idle mixture if you want a rough idle and loosen up the hydraulics if you want noisy lifters, but that's
too. Duke
Last edited by SWCDuke; 07-18-2006 at 10:52 PM.
07-19-2006, 06:46 AM
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Duke, Why would I want to change from stock powerpack cam? Well I am figuring that I could pick up maybe 10 ftlbs torgue maybe even as low as 2000rpm and maybe 20 hp at 5500rpm.
-----The stock powerpack cam is approx. 196/204 (by memory, correct this if it is wrong) with about .400 lift. The Duntov 097 is about 220/220 108/112 with the same .400 lift, (and thank you for providing these numbers awhile back).
-----Seems to me there is a happy medium in between these two cams, with more power and torque than stock. With more lift, say about .425/.435, and more aggressive ramps on a more modern design lobe and more duration there just has to be some improvement in power and torgue. Without going all the way to the Duntov, which I believe would shift the power band higher than I would like for my style of driving. Correct me if I am wrong, but I believe the Duntov 097 was designed for road racing and circle track, not as an all around street cam.
-----So if an automotive engineer, such as yourself, was designing a 283 for mild street performance right now today, seems like there is something better than these 50 year old designs?
-----As far as solid lifters, I seem to remember a distinct different sound to them compared to hyd. lifters, even when properly adjusted. It is just a pleasent little mechanical clicking, ticking, I happen to like that sound.
-----I am not saying I want a rough idle. I am saying I could live with one if that is how the cam was.
-----It comes down to this, either the stock powerpack cam and the duntov 097 are the pinnacle of cam designs for the 283; or they are not. If so fine, that is it, they are the best choices, if not then there are better cams for a given purpose. That is what I am looking to find out.
Lunati's 097 Duntov repro cam specs: http://www.holley.com/20109.asp
Lunati's street cam that looks good specs: http://www.holley.com/80350LK.asp
Isky cam for a Y-block but could be ground for a 283 specs:
http://www.iskycams.com/timingchart...._number=301444
-----The stock powerpack cam is approx. 196/204 (by memory, correct this if it is wrong) with about .400 lift. The Duntov 097 is about 220/220 108/112 with the same .400 lift, (and thank you for providing these numbers awhile back).
-----Seems to me there is a happy medium in between these two cams, with more power and torque than stock. With more lift, say about .425/.435, and more aggressive ramps on a more modern design lobe and more duration there just has to be some improvement in power and torgue. Without going all the way to the Duntov, which I believe would shift the power band higher than I would like for my style of driving. Correct me if I am wrong, but I believe the Duntov 097 was designed for road racing and circle track, not as an all around street cam.
-----So if an automotive engineer, such as yourself, was designing a 283 for mild street performance right now today, seems like there is something better than these 50 year old designs?
-----As far as solid lifters, I seem to remember a distinct different sound to them compared to hyd. lifters, even when properly adjusted. It is just a pleasent little mechanical clicking, ticking, I happen to like that sound.
-----I am not saying I want a rough idle. I am saying I could live with one if that is how the cam was.
-----It comes down to this, either the stock powerpack cam and the duntov 097 are the pinnacle of cam designs for the 283; or they are not. If so fine, that is it, they are the best choices, if not then there are better cams for a given purpose. That is what I am looking to find out.
Lunati's 097 Duntov repro cam specs: http://www.holley.com/20109.asp
Lunati's street cam that looks good specs: http://www.holley.com/80350LK.asp
Isky cam for a Y-block but could be ground for a 283 specs:
http://www.iskycams.com/timingchart...._number=301444
Last edited by CJS; 07-19-2006 at 09:48 AM.
07-19-2006, 12:33 PM
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The 283/245 has the "base engine cam", which if original is 196/196. ("Powerpack cam" refers to a '56 only mechanical lifter cam) The current 14088839 replacememt base engine cam is 194/202, and this is the take-out from crate engines than Sallee Chevrolet is selling for ten bucks.
NO OTHER CAM will make the stump pulling low end torque of this design from off-idle to 2000 revs. The 14088839 is a "modern design" with less aggressive dynamics than your OE cam. More aggressive dynamics doesn't really improve torque bandwidth or peak power that much, but sure beats up the valvetrain. That's why subsquent designs of the "base engine cam" have softer dynamics.
As I've said a zillion times before, you select the cam to make your low end torque goal, and work the heads to achieve top end power.
In the case of your small port/small valve heads, pocket porting/port matching and a multiangle valve job with improve top end power up to ten percent and extend the useable rev range by about 500 revs over what it is now without losing signficant low end torque, and you can install a 1.84" inlet valve.
Based on your stated torque bandwidth preference, this is how you should proceed.
The Duntov cam was considered a "racing cam" back in its day as SCCA production car rules required essentially "showroom stock" configuration. It was a very good "racing cam" for a 283 with the small port/valve heads, but not so good on a 327 with big port heads, which is why Chevrolet created the 30-30 cam, but it went overboard in order to give SCCA racers more power. It is a lousy street cam. The LT-1 cam was the final answer - broad torque bandwidth and a broad top end power sweet spot as evidenced by the recent thread with the dyno results, but I am hesitant to recommend the LT-1 cam for a 283 with the OE small port/small valve heads.
I still recommend the Duntov cam for 283s than had it originally, or for those who want to upgrade a 245 to a 270, but this shifts the torque curve a thousand revs up the scale and there will be a definite loss of low end torque in trade for the additional power and extra thousand useable revs at the top end.
Duke
NO OTHER CAM will make the stump pulling low end torque of this design from off-idle to 2000 revs. The 14088839 is a "modern design" with less aggressive dynamics than your OE cam. More aggressive dynamics doesn't really improve torque bandwidth or peak power that much, but sure beats up the valvetrain. That's why subsquent designs of the "base engine cam" have softer dynamics.
As I've said a zillion times before, you select the cam to make your low end torque goal, and work the heads to achieve top end power.
In the case of your small port/small valve heads, pocket porting/port matching and a multiangle valve job with improve top end power up to ten percent and extend the useable rev range by about 500 revs over what it is now without losing signficant low end torque, and you can install a 1.84" inlet valve.
Based on your stated torque bandwidth preference, this is how you should proceed.
The Duntov cam was considered a "racing cam" back in its day as SCCA production car rules required essentially "showroom stock" configuration. It was a very good "racing cam" for a 283 with the small port/valve heads, but not so good on a 327 with big port heads, which is why Chevrolet created the 30-30 cam, but it went overboard in order to give SCCA racers more power. It is a lousy street cam. The LT-1 cam was the final answer - broad torque bandwidth and a broad top end power sweet spot as evidenced by the recent thread with the dyno results, but I am hesitant to recommend the LT-1 cam for a 283 with the OE small port/small valve heads.
I still recommend the Duntov cam for 283s than had it originally, or for those who want to upgrade a 245 to a 270, but this shifts the torque curve a thousand revs up the scale and there will be a definite loss of low end torque in trade for the additional power and extra thousand useable revs at the top end.
Duke
07-19-2006, 01:42 PM
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Duke, Ok! Thanks for that analysis. So it sounds like I should keep the stock 220hp cam thats in it and go for some heads or head work. I suppost the easiest thing to do is just put on a set of out of the box brand new aluminum performance heads. Thanks, Chris 
01-17-2013, 08:35 PM
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Hey guys, great info. Thank you. I don't own a Corvette but I do own a 1960 Apache pick up truck with a 283 ci engine. Which I believe is the same engine that came in the corvette. But it was assembled differently. I'm not sure how much horsepower mine has but I would like to rebuild it to replicate the power and reliability of The Corvette of that time. I'm not looking to build the version with 315 hp. More along the lines of the 270 hp. I believe it was still able to use regular gas and was able to not completely guzzle the fuel. Can you please tell me how to convert my engine? Also please correct me if anything I've mentioned was wrong?
Thank you,
Michael
Thank you,
Michael
