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should have listened and got a smaller cam

 
80elcamino3
I love my Chevy Chevette!
Posts: 1
Joined: 02/13
Posted: 02/23/13 11:04 PM

I have a 350 bored .60 over flat top pistons a 600 cfm edelbrock 4 barrel carb.  accel distributer with a super coil new accel plugs and wires. I think i have a set of heads that were 2.02 in i believe the cast number was 844??.  I have new roller rockers but i put a 480 in 480 out comp cam in tn my el camino i can get it to have some decent hp at high rpms but when you put your foot in it the car will sputter m assuming my problem is the cam.  My question is how to get a good running car if i could get new heads and get good low end hp out of it?  Im currently running 91 through it.  Just hoping i could find some method toget all the power out of it while using the existing cam.  If not im open to any reasona le suggestion.  Thanks  

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waynep71222
My first time was in a Chevy
Posts: 218
Joined: 04/12
Posted: 02/24/13 08:16 AM

i can get it to have some decent hp at high rpms but when you put your foot in it the car will sputter m assuming my problem is the cam

question.. is this sputter you are describing.. coming off idle...

if so.. how far off idle... as soon as you start moving the throttle or at around 1200 RPMs when the mains start to come in..


you might also want to verify that the valves are NOT too tightly adjusted.. hook up a vacuum gauge to the intake manifold vacuum.. it is steady???

let me describe the fuel system

at idle.. the engine should be running only on fuel that is pulled past the tips of the idle mixture screws in the front of the carb...

as you come off idle.. the idle transition slots come into operation ... these have a restriction up in the primary booster behind the idle air bleed that sometimes needs to be checked for debris even on new carbs.. and on carbs that are run without air cleaners and air cleaner mounting gaskets..

as you increase throttle and engine speed the air flow over the venturis is strong enough to start feeding fuel from the booster venturis on the main circuit

there is also the accelerator pump discharge circuit.. .

an accurate description of your stumble will get a much closer answer...

if you had an air fuel ratio display.. you could also see if its going rich off idle, going lean which is what i expect you might have..  or some other problem... even with the HEI coil breaking down the spark at some speeds... some off shore hei coils have caused this also.. but thats a 30 buck swap to eliminate that issue..  

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pepsi1
Big Block power for the win
Posts: 940
Joined: 03/11
Posted: 02/24/13 05:26 PM

In this case your cam chose may not be the problem.

1.Either the distributor is not working properly

2.The carburetor is not working properly or is too small

3.Or the rear gear in your ElCamino are too high 2:?? verses a 3:70

I would check your rear gear first. If it is a highway gear I would
go with a lower number gear ratio.

Bob  

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pepsi1
Big Block power for the win
Posts: 940
Joined: 03/11
Posted: 02/24/13 05:26 PM

In this case your cam chose may not be the problem.

1.Either the distributor is not working properly

2.The carburetor is not working properly or is too small

3.Or the rear gear in your ElCamino are too high 2:?? verses a 3:70

I would check your rear gear first. If it is a highway gear I would
go with a lower number gear ratio.

Bob  

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pepsi1
Big Block power for the win
Posts: 940
Joined: 03/11
Posted: 02/24/13 09:30 PM

80elcamino3

A good all around rear gear ratio with a 26"
tall tire with a 2004R tarnsmission is 3:42 to 3:73.

Rear gear ratio with a 28" tall tire would
be 3:73 to 3:90 with a 2004R transmission

Rear gear ratio with a 33" tall tire would
be 3:90 to 4:10 with a 2oo4R transmission

I hope this helps, the 700R4 has nearly the same
O/D gear ratio so the final gearing would not change much

Bob  

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