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Old 09-11-2012, 06:32 AM
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300 HP/ 383...naw!

Gents; After 2 years of gathering dust I finally completed freshening up my 383 Chevy engine that's in my 1980 4 speed Camaro. I had the home ported 993 heads gone thru with new seals by a local machine shop. I installed zero gap (cheap "claimer" style) rings and a XE268 cam. The engine makes 195 to 200 lbs. of cylinder cylinder which is more than it did before (170-175). I am running cheap cast flat top pistons (again "claimer" parts) and 1 5/8" headers. I am at a loss as to the higher cylinder pressure other than the XE cam's ability to trap more cylinder pressure because of it's fast acting lobes...Harold Brookshire apparently, really does know what he's doing. The best I've seen for my combo on the net is maybe 320 horsepower and 390 lbs of torque. Anyway, that auto runs like a scalded dog and will break loose and go sideways if I'm not careful shifting gears...heck my wife makes me sleep on the sofa if I open it up with her in it....300 to 320 horsepower would not do that! Am I getting old and becoming overly easily impressed or do I have more horsepower than the desktop dyno's describe??

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Old 09-11-2012, 07:10 AM
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Only way I know to know for sure is to get the car on a dyno..that will tell the tale..Desktop dyno has it's use but it is real world that counts..

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Old 09-11-2012, 07:31 AM
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300 HP/ 383...naw!

It is time to take it to the track. This way you can figure the horsepower.
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Old 09-11-2012, 08:03 AM
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X2 take it to the track wiegh it and you should be able to calculate hp also remember not all 300hp are created equal depending where you make the power changes how it feels when u smash on the go pedal
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Old 09-11-2012, 08:12 AM
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I ran the combination on my Desktop dyno since I've been running various combinations of 350/383 Chevy prior to my build (check my gallery).
I got 344 HP @6000 and 326 Torque @5000
I think the cylinder pressure is about right for 10.0 to 1 (or higher)compression
I think the problem is the heads flow too poorly to take advantage of the larger displacement and bigger cam. I Plugged in my AFR 195 street heads and it jumped to 375 HP @ 6000 and 342 ft lb @5000
Just for fun I ran one of the cams I'm considering, a Howard Hydraulic roller #111145-10 and my AFRs and got 496 HP @ 6000 and 498 Ft lb @ 4500. Cool also was the 402 Ft lb of torque at 2000 RPM. I'll bet that would REALLY chap your wife
I've been studying "dynamic compression" and it's pretty interesting and applies to some of your questions. Google it.
After learning to input data properly, I have found that Desktop Dyno and Desktop drag to be dead on with all my cars for the last 15 years from Stock Mustangs to my big block Chevy T-Bucket to my 9.20 @ 149 Mustang drag car. Use the drag strip to verify your Desk Top Dyno results. If you are careful to input accurate data you will be pleased if you don't have to sleep on the couch too much.


Quote:
Originally Posted by dallam11 View Post
Gents; After 2 years of gathering dust I finally completed freshening up my 383 Chevy engine that's in my 1980 4 speed Camaro. I had the home ported 993 heads gone thru with new seals by a local machine shop. I installed zero gap (cheap "claimer" style) rings and a XE268 cam. The engine makes 195 to 200 lbs. of cylinder cylinder which is more than it did before (170-175). I am running cheap cast flat top pistons (again "claimer" parts) and 1 5/8" headers. I am at a loss as to the higher cylinder pressure other than the XE cam's ability to trap more cylinder pressure because of it's fast acting lobes...Harold Brookshire apparently, really does know what he's doing. The best I've seen for my combo on the net is maybe 320 horsepower and 390 lbs of torque. Anyway, that auto runs like a scalded dog and will break loose and go sideways if I'm not careful shifting gears...heck my wife makes me sleep on the sofa if I open it up with her in it....300 to 320 horsepower would not do that! Am I getting old and becoming overly easily impressed or do I have more horsepower than the desktop dyno's describe??

Last edited by Choctaw Bob; 09-11-2012 at 08:31 AM.
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Old 09-11-2012, 08:49 AM
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Very interesting and informative reply Choctaw Bob! I also listened to the other gents and called a "dyno shop" in the town next to mine concerning having my ride dynoed. When I told the shop gent (Jim) about my engine he laughed and said all of the guys with a car like mine think they have a Melrose Rocket but leave the shop with their tail between their legs! Well, according to Mr. Chactaw I have about 345 horsepower which is most the most I've seen so far and I have to believe it but frankly I think the motor has around 375HP. I remember when I first rebuilt the engine (1994) I followed David Vizard's book very closely. In his book he did not like 993 heads but he stated they could be made to run with some port work which I did. Next week or so I will belly up to the bar with 80 bucks in hand and go see Jim at the dyno shop. Of course I will state my figures on this site and we will see how close Mr. Choctaw is!
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Old 09-11-2012, 09:03 AM
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Great, I'll be looking forward to hearing about it.

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Originally Posted by dallam11 View Post
Very interesting and informative reply Choctaw Bob! I also listened to the other gents and called a "dyno shop" in the town next to mine concerning having my ride dynoed. When I told the shop gent (Jim) about my engine he laughed and said all of the guys with a car like mine think they have a Melrose Rocket but leave the shop with their tail between their legs! Well, according to Mr. Chactaw I have about 345 horsepower which is most the most I've seen so far and I have to believe it but frankly I think the motor has around 375HP. I remember when I first rebuilt the engine (1994) I followed David Vizard's book very closely. In his book he did not like 993 heads but he stated they could be made to run with some port work which I did. Next week or so I will belly up to the bar with 80 bucks in hand and go see Jim at the dyno shop. Of course I will state my figures on this site and we will see how close Mr. Choctaw is!
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Old 09-11-2012, 09:15 AM
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My neighboor did a nova with a 383. He had it limited to 5500rpm , but still was not impressed. It has the summit street strip heads, 3000 tci stall, etc. It had a 350 similar build before and it was not all that different.

Now In July, my buddy out of town, had me rebuild a $800 144 roots bm blower. We used a 114lsa blower cam on his 350 camaro. After installation it was so impressive, imediately I knew that was the way. So I cashed in a mature CD bought the new Edelbrock E force for vortec engines and did my c10 305. It was a new design eaton impeller with sneeze valve and better streetability. A 5.0L makes about 600hp with thier kit and a 8 psi pulley. Even a old BM style roots makes plenty and they are comonly under 1000 to buy it now. If you put that on a stock roller cam 350 from a truck and 800 cfm It would beat those 383 numbers and cost under $15-1600 total runner.

Mileage , power, cool factor, blowers have it all. Just consider it next time you think about stroking it, and get someone to blow it.

Last edited by spinn; 09-11-2012 at 09:21 AM.
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Old 09-11-2012, 09:17 AM
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Mr. Chactaw....If you are close to U R stated HP figures you get a prize...my wife ....if you are not close to your figures you still get my wife!!
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Old 09-11-2012, 11:37 AM
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300 HP/ 383...naw!

Going to Comp Cams website and using CamQuest and dyno results a 383 cid with 993's ported with 1.94 and 1.5 valves put out 346 hp @4500 rpms and 436 lbs torque @ 2500 rpms. If you have 2.02 and 1.6 valves the results are 370hp @ 5000 rpms and 440 lbs torque @ 3500 rpms. This is with the XE268H cam.
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Old 09-11-2012, 11:58 AM
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Send me a photo of her. I'm already married to 1 Kentucky woman. You probably should keep her if you teach her who is boss


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Mr. Chactaw....If you are close to U R stated HP figures you get a prize...my wife ....if you are not close to your figures you still get my wife!!
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Old 09-11-2012, 12:02 PM
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I think we are all in the same neighbourhood. The differences are in precise inputs.



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Originally Posted by cdminter59 View Post
Going to Comp Cams website and using CamQuest and dyno results a 383 cid with 993's ported with 1.94 and 1.5 valves put out 346 hp @4500 rpms and 436 lbs torque @ 2500 rpms. If you have 2.02 and 1.6 valves the results are 370hp @ 5000 rpms and 440 lbs torque @ 3500 rpms. This is with the XE268H cam.
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Old 09-11-2012, 12:04 PM
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Your wife..................

Hi dallam11,if your wife is a good cook,ill take her off your hands,mine is a terrible cook !!!!!!!!!!!!!
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Old 09-11-2012, 12:05 PM
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Thats why I'm building mine with all forged bottom end. I plan on a turbo charger next year.

Quote:
Originally Posted by spinn View Post
My neighboor did a nova with a 383. He had it limited to 5500rpm , but still was not impressed. It has the summit street strip heads, 3000 tci stall, etc. It had a 350 similar build before and it was not all that different.

Now In July, my buddy out of town, had me rebuild a $800 144 roots bm blower. We used a 114lsa blower cam on his 350 camaro. After installation it was so impressive, imediately I knew that was the way. So I cashed in a mature CD bought the new Edelbrock E force for vortec engines and did my c10 305. It was a new design eaton impeller with sneeze valve and better streetability. A 5.0L makes about 600hp with thier kit and a 8 psi pulley. Even a old BM style roots makes plenty and they are comonly under 1000 to buy it now. If you put that on a stock roller cam 350 from a truck and 800 cfm It would beat those 383 numbers and cost under $15-1600 total runner.

Mileage , power, cool factor, blowers have it all. Just consider it next time you think about stroking it, and get someone to blow it.
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Old 09-11-2012, 12:19 PM
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If you are talking chasis dyno then I bet 300hp and closer to 400tq on a dyno jet chasis dyno.On a mustang chasis dyno your figures will be higher
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