john910

i have a jetting question, sbc with a holley 750 79 jets primary and 80 secondarys, plugs are black? it has a comp cam. 292 501 lift, 202 intake just a mild motor, autolite #26 plugs . any help i am a dummy!!!!

BEAST477

What size sbc and what kind of rpm's are you turning it? Be honest is this a street or race engine?

john910

sbc 355 drag race 7000 max

BEAST477

Are you running power valves? Could be one is blown. Is it possible your primaries are open too far exposing the transfer slots?

john910

no power valve are out

BEAST477

Have you set your idle mixture screws on your metering blocks? If not check them. Start at 1 1/4 to 1 1/2 turns out. Is it loading up at idle or does im seem rich at all rpm's?

john910

all 4 are set at 1 1/2

TS1955

Check your float level too.

TS1955

john910

yes floats are ok. all 4 corners are 1 1/2 turns. . just don't know were to start with jets. they were new and after warming up engine i pulled the #1 plug and it was real black. funny thing is when i went in house. my white socks were black. went right thru my work pants and turned them black. i have zoomie headers. don't know if i should wait and make a pass then check them at the end of track. thanks for the help, john

TopspeedLowet

Take the Zoomies off the heads and use a conventional manifold or header and you will get some engine vaccum signal back that the zoomies are killing at idle. Beast was correct about the power valve issue, accept that you do not have enough vaccum signal at idle to keep fuel atomised at low engine speeds like a blown valve would act like.
If you love them zoomies more than performance, then you are right where you should be with that set up. Gasoline carb set ups with zoomies net no idle power or tuneability in most all cases. When you get your blower you will be all set with them zoomies.
Bruce