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estimated 350 hp

 
Nick Grantham
I love my Chevy Chevette!
Posts: 5
Joined: 11/13
Posted: 11/04/13 10:25 AM

Im brand new to this site and just wanted to see if anyone could give me  a rough estimate  of the kind  of numbers i might be abel to expect from my new build. The engine is a 350 roller motor with a one piece rear main seal. It has a forged gm crankshaft,  forged trw dome  pistons (not sure of the dome size), a 570 lift ultradyne roller cam, roller lifters, chromoly push rods,  high volume oil pump, edelbrock performer rpm heads with 70 cc combustion chambers 1.5 roller rockers and 2.02 valves, edelbrock performer rpm air gap intake, a holley  hp 750 double pumper with mechanical secondaries, a mallory billet distributor, an sfi approved fluidampr, a holley electic fuel pump and its hooked to a th350 trans with a 3,000 hughes stall converter. I was told it will have 10to1 compression.  Again im just looking for a estimate of what kind  of power i might be able to expect. Any opinions are greatly appreciated. Thank you!  

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skyeking
I mow my lawn and find Chevys
Posts: 2738
Joined: 08/09
Posted: 11/04/13 08:53 PM

Hi there,
With tuned exhausts and 230/240*  +inlet heights like yours
I would want 400 at the crank before dynoing it for more.
 Beef up that TH350 for assurance of reliabilty..Good luck.  
skyeking

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68scott385
I mow my lawn and find Chevys
Posts: 1994
Joined: 10/09
Posted: 11/05/13 12:35 AM

That's an impressive parts list. Unfortunately the real data needed to accuratelt figure power was left out. Frown

The more you guess at compression ratio and cam duration & lift numbers, the bigger the guess window of potential power output.

Here's an online compression calculator to help figure your combination. Something that seems small like one half of a point of compression can make a big difference depending on the size of the cam, port flow of the heads, and the operating range of the overall combination.

https://www.uempistons.com/index.php?main_page=calculators&type=comp&zenid=651c81114cc1d4ea7dec1151ee427d2d  
68scott385 68scott385 68scott385

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Nick Grantham
I love my Chevy Chevette!
Posts: 5
Joined: 11/13
Posted: 11/05/13 07:42 PM

Sorry i didnt realize i left out so much  info im new to all of this. The cam specs  are 253  intake  duration and 260 exhaust duration at .050, .3823 lobe lift on both the intake and exhaust, 110° lobe separation,  and .573 gross valve lift on both the intake and exhaust side. The heads are edelbrock performer rpm units with 70cc combustion chambers, 185cc intake runners and 65cc exhaust runners. I dont think the heads have been worked at all and the cam specs are off the sheet the guy gave me. I bought the complete long block from a local engine shop for $1,600.00 after they went through and freshened it all up. The guy i bought it from said it was a  10to1  compression motor. I hope this info helps!  

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Dave632
I mow my lawn and find Chevys
Posts: 2253
Joined: 07/08
Posted: 11/06/13 03:39 PM

My guess would be in the 350-400 range.  
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Nick Grantham
I love my Chevy Chevette!
Posts: 5
Joined: 11/13
Posted: 11/06/13 04:48 PM

I was kinda hoping for a higher number but i guess i wont know for sure until i get it on a dyno. Would switching to a better set of heads be worth the money or should i just work the edelbrock's that i have? I've heard mixed reviews about the edelbrock heads  

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68scott385
I mow my lawn and find Chevys
Posts: 1994
Joined: 10/09
Posted: 11/07/13 12:54 AM

A 10:1 .030 350 with Edelbrock's RPM heads & cam (234/244 @ .050 w/ .488 & .510 lift) will make ~450hp if you know how to tune it, with a bigger cam it'll produce more hp but be peakier, meaning its sweet spot will be a narrow rpm range. I wonder if the Eddy heads are enough for the cam being used. You need to double & triple check for valve spring coil bind too as my tech info says Eddy RPM heads' max lift is .575", coil bind will cause major damage real quick to any motor, new or old. Without the high stall converter and gears it'll be a dog.  
68scott385 68scott385 68scott385

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Nick Grantham
I love my Chevy Chevette!
Posts: 5
Joined: 11/13
Posted: 11/07/13 08:59 AM

Thanks for all the info! This motor was supposedly built by a shop for a customer and ran for 10,000 miles before he decided to go big block so he gave this motor back and some cash for his new one. It has all the same parts and hasjust been gone through so im guessing there shouldnt be any binding  

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tuffnuff
Moderator
Posts: 7841
Joined: 12/09
Posted: 11/07/13 10:39 AM

Nick, your combo should make 1 horse per cube, maybe at or near 400+.,. a good tune should get you there.,. keep tweaking and best of luck.

Smile  
When The Flag Drops.,.

tuffnuff

The Bull ***t Stops.,.
tuffnuff

P. Engineer, Engine Builder

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Nick Grantham
I love my Chevy Chevette!
Posts: 5
Joined: 11/13
Posted: 11/07/13 12:00 PM

Thanks for the info everyone! I do have one more question. Im gonna run a hp holley 750 double pumper with mechanical secondaries but  picked up a proform main body. I was contemplating swapping everything from my holley on to the proform  main body since I've heard it will make more power. Are the power gains worth the time to do this?  

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skyeking
I mow my lawn and find Chevys
Posts: 2738
Joined: 08/09
Posted: 11/07/13 08:24 PM

Hi there,
 One hurdle at a time.
 If you cannot do it with a Holley 750dp
 on your rig then do not throw more money
 in the fire.  There are a dozen ways to
 work the Holley..
  If you can dig this forum then buy a real
 good book on Holleys and ALL about them.
  KEEP it and do Never loan it. It will more than
  pay for itself and help you stay partially sane.
 { We are all a bit nuts anyway.]   Skyeking..  
skyeking

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dond1965
I have an SS396 tatoo
Posts: 294
Joined: 12/13
Posted: 12/02/13 10:48 PM

sir if you consider changing the valve spring package,maybe add a rev kit too,then you can swap to some crower 1.7 roller rockers. this will add lots of valve lift. but you will have to check the piston to valve clearence! that should net you a good power increase to numbers you might be happier with....good luck,enjoy  

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