Kubs

I mostly do EFI engine stuff, and the occasional rebuild of carbs so I am not very well versed in carb data. I am looking for some help on my current project.

Background: A few months ago I acquired a '71 4 speed coupe project car. It sat for 31 years before I got it, and after cleaning the fuel system, rebuilding the quadrajet, new plugs, adjust the points , etc I got it running. It ran very well! My goal with this car is some sort of resto-mod street cruiser. I have a 408ci small block shortblock that I am working to build up as I have the extra money. While I am working on that, I happened upon an old school 327ci that just kinda fell in my lap. I want to put it in and have something to play with while I build the 408.

This leads me to my first set of questions. I also got an old Holley carb to use with the 327 and some random assortment of jets, metering blocks, bowls, etc. I am pulling the #s matching engine on a stand and saving it, so I would like to leave the quadrajet alone and use the Holley I have. I found the list number on the Holley to be 3140-1. I have since found out that this carb is a 4160 style standard on 65-67 Chevelle 427 and Impala 396 engines. However, I am unable to determine which rebuild kit to get. Holley's website shows 4 kits for the 4160 style:

#37-119 a generic Renew kit for 4160
#37-1542 a generic Fast kit for 4160
#37-754 Renew kit for 750cfm 4160
#37-720 Renew kit for 600cfm 4160

How do I know which size carb I have? 750 or 600cfm? I did not see too many other numbers on it. Do I get one of the generic kits and hope all the correct gaskets are included?


Next question is, how do I rebuild this carb with my 327 in mind (jets, air bleeds, etc)? I know it will require a little bit of tuning once running, but what is a good starting point? The engine is an old school 327ci 11.5:1 compression, 30-30 cam, double hump heads with mild porting, and dual plane intake.

Any help would be greatly appreciated!

toobroketoretire

If it was for 396 and 427's it would be a 750 cfm and a generic Hygrade kit would include all of the gaskets needed for any 4160 style carburetor. The jet sizes are matched to the cfm of the carburetor and not the engine's cubic inches so leave them alone.

Sigforty

You should be able to determine the size by measuring the Venturi diameter and the diameter of the throttle blades.

MelWff

the 3140-1 Chevy part# 3868864 came with #67 jets primary. As far as the correct Renew kit, call Holley.

Kubs

Any idea what they should measure for a certain cfm?

Would #67 jets work for a more radical engine? I thought your supposed to optimize jets for the engine needs.

Sigforty

650 would have 1 5/16" primary and 1 3/8" venturi secondaries. The 750 would be 1 3/8" for all four. The throttle blades should be 1-11/16.

Kubs

Thanks. I will have to take it apart and measure.

Edit: I also have a List #3246 body and a List#3910 body. I also have some metering blocks and bowls that might match up. Would I be able to use the same throttle plate with different bodies? Whichever gives me the best combo?

Sigforty

Possibly. I am not sure about all the interchangeablity with Holley parts. There is a lot of stuff that can be swapped between holleys though.

Kubs

So I measured the 3140-1 carb and the primaries are 1-1/4, secondaries are 1-5/16, and the throttle plate is 1-9/16. Looks like I have the 600cfm version.

The 3910 measures 1-3/8 primaries, 1-7/16 secondaries and 1-11/16 at the bottom where it would bolt to the throttle plate so it appears to be a 780cfm. That being the case, it does not look like I can use, or would want to use, the smaller throttle plate with the 3910. I have 2 metering blocks with power valve holes and idle adjustment screws, and 1 block with no power valve provision. I have 2 secondary center hung float bowls, and some misc brackets. I will have to get the numbers off the metering blocks to see if I can use them or not.

I think the complete 600cfm carb would be too small for the engine I am putting it on, but I can use some parts from it to complete the 3910. All I would need to buy is a primary bowl and throttle plate I think. Everything else should come in a rebuild kit.

jnb5101

Depending upon your maximum RPM you intend the 327 to turn, the 600 CFM might be sufficient. Do the math and a 327 at 6000 RPM needs 568 CFM. GM put Qjets on these engines because the secondary will only open enough to supply the air that the engine demands. Bigger isn't always better.

Jebbysan

I strongly recommend this kit.....I keep them in stock in my garage.
Best kit out there.....

http://www.aedperformance.com/parts/...rt-4160-detail

Browse the site for other great small parts they offer.....you can really do I nice job with their stuff......it is all Holley bulk items.....but for like half the price. The bowl screws kits are a bargain too.

The Holley kits are great....but super pricey and you are left with a bunch of crap you will never use.

If you have access to an Ultrasonic cleaner....I recommend that as well.....I have a 9 litre unit and it is awesome for carbs and other things.....

I do a LOT of carb re-furbs for vintage bikes and cars. Just a suggestion.

Jebby

Kubs

The 327 is capable of about 7500rpm. This setup is very similar to the '69 Z/28 302ci that came with the 3910 780cfm carb from the factory, or the L76 327/365hp offered in '64-'66 Vettes. If I can get the pieces to put the 3910 body I have back together I would like to.

I do not have access to an ultrasonic cleaner, but have been successful in the past with carb cleaner, small brushes, and patients. Thanks for the tip on the rebuild kit though!

Kubs

So I have been doing research, and I dont really have any good pieces that fit together. To buy the remaining pieces (throttle body, metering block, jets, bowl, rebuild kit, electric choke, etc) I am looking at almost $400 for a cobbled together 780cfm vacuum secondary. I just purchased a brand new aluminum body Holley 750 Ultra double pumper with billet metering blocks and electric choke for under $500 on sale at Summit with some Summit bucks. Seems worth it to me to pay a little extra now for something I can just bolt on and adjust right out of the box.

As a side note, yes a 750cfm may be a bit big for the 327, but I am also building a 408 small block that will eventually find its way into the car and I plan to use the same carb on that.

toobroketoretire

Fortunately there are more carburetor experts in this forum than in any other place in the world so I'm sure you'll get more advice than you want.

Sigforty

Sounds like a good choice. The ultra models have a lot of tunability.