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350 Top End upgrades question

 
chevy_guy
I love my Chevy Chevette!
Posts: 9
Joined: 09/12
Posted: 09/13/12 08:53 PM

I got a 350 4 bolt and 700r tranny out of my 79 Custom deluxe. The engine has been tore down and checked for issues. I have had the block and heads cleaned and magnafluxed and now we are ready for some top end upgrades.I would like to gain as much HP/Torque as possible without replacing the heads. This leaves the cam (possible a kit with pushrods and lifters), intake and carb. Now I have read that the max lift on stock heads was .500, and when choosing a cam is there anything else I need to look out for as to not damage anything in the engine. As for the intake, I am looking at a dual plane design I like the Air-gap design that Edelbrock offers on it performer Air-gap or its performer rpm air-gap, both of these are nice. Are there any issues with these that I should know of ie...hood clearance. When choosing a carb I am thinking about the holley street avenger 670. IS this enough cfm for  the setup im looking for? All suggestions welcome.  

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pepsi1
I mow my lawn and find Chevys
Posts: 1718
Joined: 09/11
Posted: 09/13/12 09:57 PM

Not knowing what your heads are...Heres some cams. The lower the duration numbers the more torque the engine will make at a lower RPM. Now the same goes for the Lift except for you to make any horse power and/or torque you need to use a cam over .220* duration lift can go to .465 with a 1.5 rocker arm. For example look at Cam number N-L79N thats a horse power cam. compaired to Comp/Cam P/N12-305-(49).

1,The Carb is okay.

2.Your cam is up to you I have some here. You can always go to Jegs or Summit and compair their cams for their specs...Their prices will always be cheaper.

Comp/Cams P/N12-305-(49) Grind Number 246PE
.203/.212 Dur.@ .050  .429/.435 Lift good to use with factory accessories.

Comp/Cam N+300HP Factory replacement for 300HP/327
.211/.218 Dur.@.050  .426/.420 Lift Nostalgia Cam. Good to use with factory accessories.

Lunati/Cam P/N10120702LK
.219/.227 Dur.@.050  .468/.489 Lift Good to use with factory accessories

Comp/Cam P/N N-L79N
.229/.236 Dur. @.050 .468/.462 Lift Nostalgia Cam.

Lunati/Cams P/N 10120100LK
.204/214 Dur. @.050  .420/.443 Lift good torque cam and towing cam. Use with all factory accessories

Lunati/Cams P/N 10120101LK
.214/.224 Dur. @.050  .443/.465 Lift good torque cam a little more cam then 100LK.

You'll want a dual plane intake manifold. Good from idle to atleast 5500RPM.

Stay with Jegs or Summit when ordering parts.You can get a complete engine rebuild kit from any of those guys inexpensive....Your going to need to know how much the crank was turned, engine bored how much so pistons will fit and rings. Grin  Cool

Bob  

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Pontiacman2
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Posts: 8956
Joined: 09/08
Posted: 09/14/12 05:32 AM

What heads are on this engine ,casting numbers will help.
also are you running dish top pistons or flat top pistons.  
Pontiacman2
Pontiacman2

Professional Hi-performance engine builder

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chevy_guy
I love my Chevy Chevette!
Posts: 9
Joined: 09/12
Posted: 09/14/12 07:28 AM

The casting on the block was 10066036-Standard Goodwrench crate motor, 2-piece rear seal, "Hecho en Mexico"; 249 HP @ 5,000 RPM/304 Ft/Lbs @ 3,500 RPM; 8.5:1 compression ratio.

The casting on the heads is 33417369, 1.94" Intake valve, 1.50" Exhaust Valve, 76cc Combustion Chamber, 7 Bolt style Exhaust Flange Standard

Cam Specs:Hydralic Flat tappet Camshaft- #14088839
Intake Lift-.383" Exhaust Lift-.401"
Intake Duration @ .050"- 194 Exhaust Duration @.050"- 202
Lobe Seperation-112

8.3435 cc flat top cast pistons  

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pepsi1
I mow my lawn and find Chevys
Posts: 1718
Joined: 09/11
Posted: 09/14/12 11:27 AM

Chevy_guy:

I don't even show those heads. So they are from a newer crate engine. So as far as any Horse Power gains you need to stuff the biggest Cam you can. So your at a catch 22. .500 lift and .226 duration would be the biggest cam you can use with all your factory accessoies. Not much else you can for power. Even if you tried to port those heads you may hit water. There is no other way to make horse power...

Just a little info: If you can get to a swap meet you may be able to get an earlier set of castings. Even if you installed a 64cc cylinder head on that 8:5:1 piston you will be at the limit range of 93 octane gas...You can always install a thicker head gasket if it where to come to that....

Bob  

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chevy_guy
I love my Chevy Chevette!
Posts: 9
Joined: 09/12
Posted: 09/14/12 03:04 PM

Okay say if I were to bolt on a pair of those 2.02/1.60 camel hump heads with the .550 lift springs, would this allow me to make more power?  

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Pontiacman2
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Posts: 8956
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Posted: 09/14/12 03:23 PM

Yes with a decent cam choice and those double hump heads you can make a good bit more power then you have now but may need to use premium pump gas.  
Pontiacman2
Pontiacman2

Professional Hi-performance engine builder

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skyeking
I mow my lawn and find Chevys
Posts: 2738
Joined: 08/09
Posted: 09/14/12 04:04 PM

Hi there,
  I have used a 194//204 cam with 1.6 rockers
  [did not want to do the hard miles of changing
  a cam in the Jaguar.]
   No noticable loss in torque and power range up
  by 450 rpm on dyno. Only needed Holley 600 cfm
  for power and economy..All std with jets being
  66 up front and 69 for vac secondaries...Ram
  horn exhausts into 2.5" twin pipes..X over not
  an advantaage with cam.. All the best ...
   Hi LEMONADE dodger...Skyeking...  
skyeking

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skyeking
I mow my lawn and find Chevys
Posts: 2738
Joined: 08/09
Posted: 09/14/12 04:04 PM

Hi there,
  I have used a 194//204 cam with 1.6 rockers
  [did not want to do the hard miles of changing
  a cam in the Jaguar.]
   No noticable loss in torque and power range up
  by 450 rpm on dyno. Only needed Holley 600 cfm
  for power and economy..All std with jets being
  66 up front and 69 for vac secondaries...Ram
  horn exhausts into 2.5" twin pipes..X over not
  an advantaage with cam.. All the best ...
   Hi LEMONADE dodger...Skyeking...  
skyeking

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geargrabber
V-6 Camaros rule!
Posts: 74
Joined: 07/12
Posted: 09/14/12 05:49 PM

I put together a combination similar to what you describe, but I used .100" dome pistons to bump the compression, and a 214/224 duration .442/.465 lift cam, performer rpm intake, and....quadrajet (I`ll never try to use one again). Good combination as it was but the kid I sold it to put a new edelbrock carb and better duals with x pipe...I never got to check it first hand but heard many stories about how well it ran..in a `87 full size blazer, 3.73 gear, and 33" tires.  

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pepsi1
I mow my lawn and find Chevys
Posts: 1718
Joined: 09/11
Posted: 09/14/12 09:00 PM

You got it Skyeking and Geargrabber.

Everyone thinks you need to install a cam that idles at 1400 RPM. I've used that cam and got the same results. It's the combination of the parts. Not one part all by itself...

Bob  

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