Vacuum pipework?

[kayjayd]

I'm running a chevy with Edelbrock airgap intake and Holley 750 vac sec carb. What plumbing do I need to operate the vac secondaries and the servo for the brakes? Is there anything else I need to consider?

Pictures, which ports, and thread sizes for the fittings etc. would be great

Thanks in advance

[kayjayd]

Anyone?

[ti]

Originally Posted by kayjayd

I'm running a chevy with Edelbrock airgap intake and Holley 750 vac sec carb. What plumbing do I need to operate the vac secondaries and the servo for the brakes? Is there anything else I need to consider?

Pictures, which ports, and thread sizes for the fittings etc. would be great

Thanks in advance

My set-up is different to yours - ie ford and holly but should be the same principle. You will not need any plumbing for the vac secondaries as they are activated by the vac created by the engine, also the plumbing for the servo should go to the power brake fitting on the carb - look at your info sheet that came with the carb to make sure which one it is.

[kayjayd]

Thanks Ti.

Further to the above after reading various articles it seems I need to connect the large vac port on the back of the Holley to my PCV (which is where it is now) and connect my brake servo line to the port in the inlet manifold (Edelbrock airgap).

Does anyone know what thread size this is? I've searched and I think it may be 3/8 NPT.

Next thing is where do I get a fitting to go in there as it's going to have to be pretty low profile to fit under the fuel bowl. I've tried Real Steel and "Computer says NO".

[Martyn-ak427]

Hi Kev,

I am running an Edelbrock RPM Airgap with my Holley 750cfm & if I recall the female tapping in my manifold is 3/8 NPT.

I used a 3/8 NPT male to -06 JIC male adaptor then used a -06 JIC female to 90 degree barbed hose-end fitting. I ordered these fittings from Speedflow, (08702 250097) however their not particularly cheap as the are anodised ally but they do look good & it just clears my fuel rail on my carb.

If you decide to go down this route please double check your setup as it may differ from mine & I would hate to give you duff info.

Regards,
Martyn

[kayjayd]

Originally Posted by Martyn-ak427

Hi Kev,

I am running an Edelbrock RPM Airgap with my Holley 750cfm & if I recall the female tapping in my manifold is 3/8 NPT.

I used a 3/8 NPT male to -06 JIC male adaptor then used a -06 JIC female to 90 degree barbed hose-end fitting. I ordered these fittings from Speedflow, (08702 250097) however their not particularly cheap as the are anodised ally but they do look good & it just clears my fuel rail on my carb.

If you decide to go down this route please double check your setup as it may differ from mine & I would hate to give you duff info.

Regards,
Martyn

That's sounds about spot on Martyn - thanks. I'll make a few more calls now

[ldtopham]

Originally Posted by kayjayd

That's sounds about spot on Martyn - thanks. I'll make a few more calls now

Kev, for supply of unions try Think Automotive (google). They list pretty much everything and I have always found them to be competative on price.

[kayjayd]

Originally Posted by ldtopham

Kev, for supply of unions try Think Automotive (google). They list pretty much everything and I have always found them to be competative on price.

Thanks Lee - sorted.