Blocking off secondaries on four barrel

[stevo]

Situation: Going to be running a tunnel ram on the street on a small-cube engine and have a pair of the Holley 450 (9776) tunnel ram carbs. These carbs are mechanical secondaries but are single-pumper carbs, there is no metering plate or accelerator pump for the secondaries, but they are mechanical secondaries. From what I have read these carbs cause a bad tip-in lean situation. Would there be a reason I couldn't remove the linkage to the secondaries and hard-wire the secondaries closed? I am thinking there is no secondary idle circuit on them so there wouldn't be an issue. The tunnel ram will be used mainly for looks.

Stevo

[Fordblue625]

The tunnel ram will be used mainly for looks.

Stevo

Be sure to top it off with a hilborn scoop for that extra touch of class.

[stevo]

Be sure to top it off with a hilborn scoop for that extra touch of class.

It is going on a rat-rod themed project...

So, have any input on the question?

Stevo

[Fordblue625]

It is going on a rat-rod themed project...

So, have any input on the question?

Stevo

I don't see any issue with blocking them off if it's for looks and it won't see any real track/road time. If it sees road time, might be a better idea to swap in on of the quickfuel replacement plates which would allow for you to jet the secondaries to try to mitigate some of the tip in bog.

[Damnittsteve]

or you could trade it to any guy with a 2bbl

[stevo]

I thought about going with a pair of the Holley 350 cfm two barrels, but since the dirt-track racers scoop them up they are expensive used for a carb, and are around $300 each new. And the carbs are placed inline on this ram, so the 450's only clear with about 1/4" between the fuel bowls so adding carbs with secondary plates and accelerator pumps won't fit.
I think I'll try it as all it takes is removing the secondary linkage and adding a linkage that keeps the secondary closed, and just keep an eye out for the proper 2-barrels.

EDIT: It took a second, but I realized what you mean about the plates, I was thinking secondary metering blocks, those plates may work along with adding a 500cc accelerator pump on each one and playing with the pump shot nozzles/ramps.

Stevo

[shumpertdavid]

Should be no ill side effects from taking the secondaries out of the picture. If the butterflies don't open then fuel won't be pulled through the venturies, and you'll be left with a glorified 2 bbl carb. Or look into a pair of holley 390's with vacuum secondaries, or possibly convert the 450's over to vacuum secondaries.

[Fordblue625]

EDIT: It took a second, but I realized what you mean about the plates, I was thinking secondary metering blocks, those plates may work along with adding a 500cc accelerator pump on each one and playing with the pump shot nozzles/ramps.

Stevo

You got it. The plates won't affect the inline fit. This and the addition of the accelerator pump is probably the only way you'll end up being satisfied with those in a long term application.

[jyro]

just remove the linkage bar, you won't need to wire them closed

there is a metering plate under the bowl to the main body area. that's how you change jets, change the metering plate.http://www.carid.com/holley/item-215...FYKPPAodWBEABQ