Bear in mind that the altitude here is a mile high, in addition to the things you mentioned.

It came with a 70x52 meetering rods, & the book says 100 main jets.  (haven't had to pull the top to see the jets) It also came with the orange springs for the power pistons.

I ended up using 73x47 rods with the same orange springs. 

Like I said before, the throttle response is what I was most impressed with.  The torque is much improved over anything I had ever been able to come up with before.  By that I mean it is an off idle torque that carries through into the power circuit. 

Fyi, I have a 301, with ported c1te heads with 1.78 intakes, e-4 isky cam, 1.6 roller rockers.

I have same carb and also running rich.  Know there will be some difference due to cam, heads, etc but what combination springs and rods  did you wind up using?

TC - Austin, TX

You gotta have the right tools and know how to use 'em.

TC - Austin, Texas

Ok, so I finally broke down & bought a 600cfm Edelbrock. 

Out of the box ran ok, rich, but ok. 

Some rod changes, & trial & error on a few springs, & it has so much better response than I ever could get with the 4100's I used I am actually surprised! The only bad thing is now a brake line has decided to burst, so so much for my 240.00 carb!!

when converting be sure to epoxy over the small vaccumm hole where the choke housing normally draws from.

Some great info can be found on this site & the host seems to be well versed in autolites & all applications including y's.

http://www.network54.com/Forum/88781/

I used a universal conversion kit on my 2100, which I believe has the same auto choke as the 4100.  They are inexpensive and available at most all auto stores.  Installation is easy.

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.

56 Club Sedan 312 bored 40 over, balanced. Stock ECZ-C heads, 57 dist. , Clay Smith 270 Cam. Ford 57 E Code manifold with two 500 CFM Edelbrocks. Runs Strong. No tuning out of the box carbs.



Jim

  Jim Rowe Elkhorn, NE

Two factory teapots on my 56 T Bird

One short

One stout

I'm a little teapot-short and stout

Ok, so even though the throttle response was crisp on the rochester 4-G, I was dissapointed once on the road.  Low end was still incredible, however I think the port for the fuel to the secondary float is either clogged, or the secondary float is stuck in the up possition.  when I opened up the secondary the thing didn't get any additional fuel.  Sounded real bad.   What can I say, I rebuilt this thing like 10 years ago, It's been sitting wrapped in plastic since then. 

On the flip side, I am currently making a solid attempt to bore the secondary throttle bores on my 1.08 to allow for the larger butterflies from the 1.12.  The venturi is already a shade larger from my earlier re-working a few years ago.  My hope is to have my own version of a spreadbore 4100 that will be somewhere around 550 or so cfm, the bulk of that on the secondary side. We'll se if I can bore a round hole since I don't exactly have a machine shop here!

I could end up dissapointed & calling up BG for a 525 road demon jr!

New Punk,

Your right I did say that. I am running a Holley 4150 (600CFM) and it runs great. It might be oversized since it is sitting on a stock motor. I'm not sure what jets are in it, but they must be small for it does not run rich. As for the B&M Mega scoop, I was quite surprised as to how restrictive the filter element was. It looks like a K&N filter. Even after washing it, it didn't seem to make much difference. I got better performance with a regular 10" open element Fram, paper filter? I have now finished building my ram air box to mate with my scoop, and will be rebuilding my spare carb this winter and playing with the jetting.

Rob

I love the smell of burning rubber in the morning!

570 Holley Street Avenger - Runs pretty well, but I've had a hard time getting a good fuel mix across all RPM.

Before I change carbs, I'm going to pull my Holley Megascoop air cleaner and try something else.  I was told by Rob on here that they don't work very well and I should replace it with a velocity stack.  I've also read that this carb might be a little big???

- John

John: Lake Forest, IL



'57 Fairlane 500 - Looking better every day.