A 750 double pumper for a small block Ford is a lot. If it was a circle
track racer with lots of breathing capacity then I would still say it is at
the upper end of what one needs. I would go to a 600 cfm carb....with
vacuum assist secondaries. What are the cam specs? Where are you running
the timing at....Did you advance or retard the cam timing? (lower small
gear of timing set)... Is your Unilite a mechanical advance unit or vaccum
assisted advance...and where is it set? Poor idling can also be related to
having a vaccum leak.
Chris in Trinidad
"Dr. T. Y. McDowell" wrote:
> Tigers,
> I've had an ongoing problem with my new 302 engine fouling spark plugs.
> In my last engine issue e-mail bomb, it was the consensus of the group
> that my cam timing was off. Well, it was - one tooth.
> Now, it's perfect. My very knowledgeable friend rebuilt a Holley 750
> double pumper (this is the 3rd carb I've had on the car). At first when
> we refired the engine yesterday we could not get it to idle unless the
> RPM was @1,000 (even after the temperature came up. Bu we figured that
> because the motor is a custom built (shaved deck, balanced and
> blueprinted, Keith Black pistons, Trick Flow heads, aluminum radiator,
> Crane Cam , Mallory Unilite, MSD coil, Holley high performance fuel
> pump/regulator, etc, where it would idle was where to set it.
>
> Because I kept fouling the plugs, Trick Flow recommended that I move up
> two heat ranges in spark plugs, which I did.
> The temperature with a 160 thermostat was at less than 140 going down
> the road. We thought that the car was sluggish because it was running
> cold, which was exactly how it felt. I installed a 195 thermostat.
>
> After a very short period of running time the car is acting like the
> plugs are fouled again (backfiring under throttle through the carb and
> exhaust, but idling lovely). I took it out yesterday and ran out of
> road. It seems like it wants to clear itself up but doesn't.
>
> This morning I pulled the plugs on # 1 and 2 - they're fine.
>
> I'm at my wits end. Any help/suggestions will be more than
> appreciated. The good news is that I finally know that the car, when
> straightened out, will be awesome.
>
> Please help me get this problem ironed out before the real snow starts
> to fly. I need to drive this car! Thanks in advance.
>
> Tym McDowell
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