Holley base gasket question

[Whaler]

Hi gang
I have the Holley 850 Model 4150, which I will show both a link and a pic

Holley Carb I have




Now heres my question...I have the Edelbrock RPM intake. The base/carb flange is simply a big square bore with the metal rib in the middle, running from front to back.



I have bought enzo's turkey pan and while farting around with the cutouts etc I went for another carb gasket....This is the first time I had really paid any attention to the bottom of the carb and all its intricate porting and runs between the primary and secondaries.

My question is I guess I can't use a simple open gasket the big square style...can I ?

I was wondering what exactly do I need to seal off the bottom of the carb properly for all the little porting routes to function properly...what's wilder is that the metal to back up the gasket properly just won't seem to be there in the edelbrock RPM flange.

I wish I could post a pic of the carb upside down for you guys to see what I am getting at.

Heres a pic of the gasket I believe i need...if so do I need two of the same with the turkey pan?? I have the 1 3/4" butterflies on prim. and sec.

Gasket info link



There are four duct/channels for flow between the 4 butterflies in the very center, like a cross, as well there ..other channels cut in the flange on the outer edge of the flange.

Anyone else using this combination?? I imagine the bottom of a 750 double pumper shouldn't be much different. What should I do?

Tim

[Jack21]

Haven't played with "Turkey Pans" per se', but have played with heat shields that go in between carb and intake. And most of us sitting here reading this know what the underside (and the inside) of a Holley looks like, perhaps more than we care to admit.

The main thing is to seal the intake and carb from vacuum leaks. A vacuum leak will upset the fuel/air ratio. With a 180 deg intake as shown, we want to seal the right and left sides from vacuum leaks as best as possible, although it's not absolutely critical that this be done. Use the thick gasket you've shown on the intake, use a 4 hole gasket between the sheet metal and the carb. Coat the mating surfaces with ordinary wheel bearing grease (even Vaselene will work).

[Whaler]

Hi Jack21
Thanks for the help. I have looked thru the gasket page and there are only 2 gaskets that have the 1 3/4 butterflies. There is another that is listed but it says it has studs as well...turns out to be quite different in that the centre rib section is gone completely and it is more of an open square bore, more like what I currently have and can't use.


Holley Gaskets

The turkey pan opening is simply an open square bore. I need to keep closer mating surfaces if I use a different gasket on the intake to pan as compared to the pan to carb i will introduce sealing gaps. I do need that center rib as well as some gasket material on the outer edges for the carb flange which has some porting routes. Why not use 2 of the same??

Getting the carb up off the bottom of the turkey pan (5/16")would be helpful as well as I had some clearance issues at each end where thge bottom pump levers of each float bowl and their pivots, actually contacted the bottom of the pan valley. I have slotted for those anyway.. the rise wouldn't hurt.

The four hole style gasket doesn't seem available for 1 3/4" butterflies from Holley at least.

Tim

[Whaler]

I found a gasket made by Felpro



Fel-Pro
FP-1909
(4150-850)

I assume this means a 4150 and hopefully for an 850

no details on butterfly size..maybe I will ask about this gasket a the partsplace and take my carb as well

It too would also give me my necessary center section

Tim

[Jack21]

Any speed shop will have gaskets that fit Holley square bore. Holley, Fel Pro, Mr. Gasket, etc. They can be trimmed with exacto knife. If push comes to shove, get a roll of gasket material and make them. Can make spacers out of sheet aluminum stock also. Or get heat shield kit, use as a spacer, and cut off what you don't need. Just remember to use longer carb studs, and grease the mating surfaces so you get a good vacuum seal.

[Whaler]

of the inner surfaces I am worried get missed by the simple open bore square flange gasket

[wicked fast]

Whaler,
Happy to see you using RED loctite on the base screws. I lost a small block chevy years ago to a carb screw. Got past the valves and bounced around unitl it cracked the cylinder wall.
I too am using the exact set up.
I am going to use a 4-hole gasket between carb and turkey pan,
open square gasket between turkey pan and the intake.