Carburetor parts interchangability questions, 4180, 4180C, 4160

[bigjason_5]

Ok, I have an original Holley carb for the Crimson Cat. It is from 1983, and I believe it is a 4180. If I am wrong with anything here, please correct me. All I know is what I think I remember or what I've been able to find with a couple quick searches. My '85 Capri has a 4180C, right? First of all, what are the differences? Is one better than the other? Is it just a couple of internal parts? And if so, are they interchangable?

Ok, next, I have an extra carb, which is pretty much a parts carb. I could get it back together, but the screws broke off for the throttle plates, so it would need some work. Now, I "think" this carb is a 4160. It does not have a secondary metering block, it has a metering plate. It has only one fuel inlet, but it is not at the same angle as the factory one, it just comes out the side of the front bowl at the top (driver side). I think that is pretty irrelevant, but just thought I'd mention it.

My question is, I have read and tried to understand the upgrades to the 4180C in the thread put together about that, but I guess I don't fully understand carbs, because the procedure is foggy to me. I'm wondering if the metering plate, or any other parts of this carb are interchangable with the 4180. If so, would it be to any advantage to use them? I need to rebuild the 4180, so I'm taking it apart either way. I just want to get the best parts back in it. How can I tell what size jets it has? The jets mount at a different angle on the two carbs. Does that matter? Can or should I swap them?

I guess what I'm looking for is, if any of you carb savvy guys are out there, what would you look for and do? By the way, this carb would most likely be going on the Crimson Cat, which is unmodified except for some missing emissions components, which will be going back on when I get them. Thanks.

[85stanggt]

First, all 5.0's from 83-85 got 4180C's.

Your Crimson Cat should have a 4180C with a casting date from 1983. It should have a different choke setup than the 1985 E5ZE carbs had. There are some other differences, but the choke setup for the "exhaust manifold equipped cars" is the main difference.

The fact that you say the parts carb has the jets at a different angle makes me think that it is a 4160. Do they point straight out? If yes, then it's probably a 4160 like you said, but without a picture or list # that's just a guess.

The metering plates can be used between the carbs, but they just require different gaskets from what I gather (not positive on this one).

In terms of parts usage, I'd use as much as possible from your stock carb. Stuff like bowl screws can be interchanged, but the metering block, metering plate, baseplate, and bowls are unique to 4180's. I believe even the choke is different.

[Zap's 85 GT]

Holley changed around the 4160's in the early-mid 90's and its sometimes difficult to know exactly what you've got. Usually there were changes in the primary metering block design. Some used the accelerator pump transfer tube like the 4180 and the earlier ones did not.

Swapping metering blocks wont work. The 4180(angled main jets) has the idle mixture screws in the base plate. The 4160(straight main jets) has them in the metering block. So it wont work no matter what you do.

Metering plates. I couldn't say. I'd just keep the original 4180 parts together for now. Get it running good, then play with the parts swapping later.

The only mod I ever did to my original GT's 4180 was to enlarge the IFR hole from the original .028" to .030". The restrictors are hidden behind the main jets in the metering block. You'll need a tiny drill bit set which they sell on eBay for pretty cheap. It made a world of difference in tip-in(transition) and cruise. These carbs were tuned pretty lean from the factory and that mod helped really bring it back alive. Even with the mod I still managed 24mpg's with 3.73's and passed an Albuquerque emissions test with a B-303 cam so its not going to cause you any grief. I'm still using that carb on my 82 F-250's 302 and it runs great on the truck too.

Do a good clean and rebuild on the 4180 and the IFR mod and I think you'll be quite pleased.

[85stanggt]

Drilling the IFR's really made that big of a difference? I just put bigger jets in and it helped alot, but maybe I should drill out the IFR and put the old jets back in? Have you ever drilled out the IFR's in the secondary metering plate?