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supercharger

1K views 10 replies 6 participants last post by  T-bucket23 
#1 ·
Good Morning, I have chev. 350 that i had friend put 671 weiand and dart heads on engine. We are having problem with engine not having full power from 1-10 mph, after you get to about 10 mph engine seems to be running good. We have timing set little high,39 because it did not want to idle if we lower it . engine has 2 edelbrock 600's, small cam spec. unknown, dart heads 72cc. It is very cold natured when first starting it but settles in with good idle after about 1-2 minutes. I pulled 3 plugs and see a little gas on plugs but not much, and they are black but not burnt. Now my question, do you think i'm getting to much fuel for my engine or is my friends cheap timming light bad,etc
 
#2 ·
What's your initial timing, certainly not 39*? What RPM is the timing all in? Are the plugs black after a hard run and shut off or at idle?

Out of curiosity, what's been done to the motor, decked, heads cut? What's your static c.r.?

You obviously have some tuning problems, idle mixture, timing are out of whack. Do the carbs have chokes, it so are they opening when warm? I';m not familiar with Edelbrocks, but have the carbs been boost referenced? A little raw fuel on the plugs is a little too much, adjust your idle mix for starters.

Temperamental cold operation is part of the blower game, let the motor warm up before hitting the streets.
 
#3 ·
I figured someone would respond and make me/us look stupid. I called guy who set engine up and he did not know the initial timing, he claims to have set advance at 39 and said he could not back off it anymore because it did not want to idle. As for plugs, we just put them in 2 days ago and they do not look terrible, black yes and very little gas(wet) on them. As for engine, when i bought car it had small 177 weiand blower with single carb. and ran good. I do know it's bored 60 over and has mild cam. Sorry thats about all we know about engine. Thanks for your reply
 
#7 ·
We have edelbrock 600 (2) on engine. They were pretty close out of the box. I just drove it and it has very poor power till u get past 10 mph then it seems ready to go. I'm wondering if this could b a timing issue or to much fuel for this motor
 
#9 ·
1200 CFM is a lot of Carburetor for a 350 and for that reason alone it is very important to have them set up correctly. If your new plugs are black and you see any fuel on them (which you do) you are literally drowning the motor.

As said make sure you have Blow Through Carbs, start from scratch and set up the timing and then adjust the carbs. As also mentioned a correct vac source is essential

Note: A vacuum hose must be connected from the power valve to a vacuum source on the lower manifold. Failure to connect this port to a manifold vacuum will allow the power valve to remain open at idle, causing an excessively rich fuel mixture.

Holley Supercharger Carburetors | Holley

I had (2) Blow Through 750's on my Blown 502 with a 871 and I drove it for well over 3 years in winter spring summer and fall. Mine was a rapped ape straight off idle all the way up the 8500 RPM but then again it was a fully built solid roller motor with about 1000 HP, LOL...

My Carb Set Up

 
#11 ·
That is a lot of CFM for a stock 350. Not knowing the cam spec is a huge stumbling block to proper tuning.
I would try blocking off the rear carb temporarily to see if it runs better.
I dont know a lot about Edlebrock carbs but not many carbs will be close out of the box for a supercharger application.
I will be honest, the 177 is probably a better choice for the street, doesnt look as cool but it is much better suited to street driving.
 
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