Holley 4160 (1850-3) carburetor on 351C-4V '71 Mach 1

Hi,

I have nearly finished the restoration of my '71 Mach 1 (351C 4V / 4 speed toploader). Last thing I did was to install the engine, and it runs great. Unfortunately I can't drive the car yet because the windshield still needs to be installed :-(((

Now on to the problem: The original Autolite 4300 carburetor is bejond use, and I doubt it is worth rebuilding. I have currently mounted a Holley 600 cfm (1850-3) on the stock intake. Although it runs without any problems, the Holley square bore pattern doesn't fit the intake spread bore pattern and probably causes performance loss.

- Is there an adapter plate I can mount between the intake and carburetor?

- Would the air cleaner still fit under my ram air hood?

- Should I better buy a 4300 or have mine rebuilt?

Thank you, Manfred

I don't think you need a spacer I doubt you are losing much performance.I had my holley right on the intake without any problems.what I did do later on was machine the intake.

72Fastback provides a great solution.

Dependent upon what you eventually want, you might also consider having one of the professional carburetor rebuilders take a look at your 4300 or at least contact them to see if you want to use that approach.

I say this based on your having inferred that you are "restoring" the car. One company who I have heard is pretty good is:

http://ponycarburetors.com/

I have not personally used their services.

Congratulations on your restoration efforts!

BT

I also used jb weld to fill the exhaust hole that way you won't need the gasket with the stainless steel insert.

Hi,

thanks for the replies and the idea to modify the intake. I already installed the Holley directly on the original intake, but the pictures of the modification are great.

It is tempting to have the original carburetor restored, but >$600,- is a lot of money.

Thanks, Manfred

Hi,

I have nearly finished the restoration of my '71 Mach 1 (351C 4V / 4 speed toploader). Last thing I did was to install the engine, and it runs great. Unfortunately I can't drive the car yet because the windshield still needs to be installed :-(((

Now on to the problem: The original Autolite 4300 carburetor is bejond use, and I doubt it is worth rebuilding. I have currently mounted a Holley 600 cfm (1850-3) on the stock intake. Although it runs without any problems, the Holley square bore pattern doesn't fit the intake spread bore pattern and probably causes performance loss.

- Is there an adapter plate I can mount between the intake and carburetor?

- Would the air cleaner still fit under my ram air hood?

- Should I better buy a 4300 or have mine rebuilt?

Thank you, Manfred

Click to expand...

I'm going through about the same thing.I have a original 73,715 cfm with no kickdown. I,ve been looking at edelbrock.com reconditioned 750 cfm. They have 600 cfm. I also heard Pony carbs was good. I think I will use a spacer. MB

I don't think you need a spacer I doubt you are losing much performance.I had my holley right on the intake without any problems.what I did do later on was machine the intake.

Click to expand...

Did you notice a performance difference with the manifold machined to that configuration?

Mike

I have a trans-dapt carb adapter (2199) off my spead-bore manifold. Spread-bore to square-bore. It worked great but I changed to the air gap manifold and no longer need it. Let me know if you're interested in it. $25.00 + shipping.

The primary throttle bore presents no problem, for it is the same on the intake, the Holley 4160 (600CFM), and the Autolite 4300A (600CFM): 1-9/16".

The main concern is the difference on the secondaries, for the secondary throttle bore of the intake is 1-11/16" (to match the 4300A), while the Holley has the same 1-9/16" throttle bores - a 3/16" difference. It's such a mild spreadbore that most people mistake them for squarebores without bothering to look close enough.

To my knowledge, no adapter exists. If the 3/16" difference matters that much to you, you are pretty much stuck swapping the intake to one with 1-9/16" bores throughout.

That said, I chose to mount my 4160 directly onto my '71s existing manifold. I'm not too concerned about the fit - the whole carb has about half a millimeter of play on the shafts, and the factory boring of the manifold is pretty crude to begin with.

You might wish to look at my thread on the same subject: http://www.7173mustangs.com/thread-carb-swap-options-with-4300a-equipped-m-code-71-351c?page=2

I have a trans-dapt carb adapter (2199) off my spead-bore manifold. Spread-bore to square-bore. It worked great but I changed to the air gap manifold and no longer need it. Let me know if you're interested in it. $25.00 + shipping.

Click to expand...

That adapter won't work for him - that adapter is for 4300D spreadbore intakes with 2" secondaries. Those were used on the '72/73 4BBL intakes only (and later Ford intakes paired with the 4300D or 4350).

-Kurt

Dough!! Thanks for the clarification Kurt.