Holley 4010 top cover thread size

[Gaz64]

Gentlemen,

I have a Holley 4010 750 DP in reasonable condition of which I'd like to try on one of my cars.

It has some "soft threads" that hold the top lid on.

I'd like to helicoil them, my research tells me the thread is 8-32 UNC.

Can somebody verify this before I buy a helicoil kit?

Thank you in advance.

[Gaz64]

Lots of views, but no answer yet.

Does anybody know?

Can anybody help me, or steer me in the right direction?

[FWB]

measure the screw that came out and put a thread gauge on it. most holley books don't break down thread sizes. a 8-32 has a theoretical major diameter of .159 inches
the minor hole size would be approx .136 inches......

[tnewland]

Originally Posted by Gaz64

Gentlemen,

I have a Holley 4010 750 DP in reasonable condition of which I'd like to try on one of my cars.

It has some "soft threads" that hold the top lid on.

I'd like to helicoil them, my research tells me the thread is 8-32 UNC.

Can somebody verify this before I buy a helicoil kit?

Thank you in advance.

I just came in from the garage after having checked my Holley 4010 (600 CFM, vacuum secondary). The stock Holley Torx head screws used to secure the top cover are tricky. It's hard to measure the thread diameter because the shaft is "lobed". Turn the shaft in your fingers to feel what I mean. Bottom line: I didn't want any "modern" style fasteners in my Shelby so I switched them out for 10-32 NF conventional headed machine screws to secure the top cover. The new screws fit perfectly. If your carb is anything like mine, and I think it is, you want the 10-32 NF Helicoil kit. Cheers, Tom

[Gaz64]

Originally Posted by tnewland

I just came in from the garage after having checked my Holley 4010 (600 CFM, vacuum secondary). The stock Holley Torx head screws used to secure the top cover are tricky. It's hard to measure the thread diameter because the shaft is "lobed". Turn the shaft in your fingers to feel what I mean. Bottom line: I didn't want any "modern" style fasteners in my Shelby so I switched them out for 10-32 NF conventional headed machine screws to secure the top cover. The new screws fit perfectly. If your carb is anything like mine, and I think it is, you want the 10-32 NF Helicoil kit. Cheers, Tom

Tom,

Thanks very much, I know what you mean, I'll go for a 10-32 helicoil kit.