I’d been wanting to put a 4 barrel carb on the Mustang’s mostly stock 289. By “mostly stock” I mean I’ve put in a different cam and done some minor head porting – nothing fancy, but they should flow a little better tan they did. It’s never going to be a race engine, for sure. So the prospect of dropping over $700 to put a 4V intake and carburetor on it was not terribly attractive to me, and I’d pretty much resolved to just put the old 2-barrel back on it.
A few days ago I saw the exact carburetor I was looking to buy listed on Facebook Marketplace, by a local seller. He said ti needed rebuilding, as it had leaked gas everywhere one day and he just replaced it with a different carb. Since there’s not a lot that a rebuild kit won’t fix, I offered him half what he was asking and he took it. So, $75 later I have the carb in hand.
Teardown revealed the likely cause of his problem – the power valve was packed solid with some sort of white flaky crud that I thought at first was aluminum corrosion. If it was, it didn’t come from the carb – there’s no trace of pitting or corrosion anywhere in it. The rebuild kit comes with a new power valve as well as the two fuel valves that were also candidates for being the cause of his problem. For a total of just a bit under $150 I’ll end up with a fresh 4-barrel for the car. I splurged on a new intake for it. There was an intake listed locally also, but it was a no-name – probably some Chinese copy of an Edelbrock manifold that I’d already decided against. I ordered a Weiand Street Warrior. I’m sure I’ll end up needing the odd bit or two for the throttle and kickdown linkages, btu I haven’t ordered anything yet. I’ll see what can be taken from the old 2100 2-barrel and reused.
I hadn’t torn down a carburetor for a car in many years, and I don’t recall ever having done a 4-barrel. Most – actually I think all – of the carb rebuilds I’e done were Ford Autolite 2100 2-barrels, which I had on an AMC and a Mustang. There have been no surprises here, and it’s cleaning up nicely while I wait for delivery of the parts order from Summit. With a little more cleaning I’ll be ready to put it back together with new guts.
This one is a Summit Racing manufactured version of a Holley 4010, which was largely based on an Autolite 4100 with some Holley-ish modifications. I like it because it’s got the 4100’s annular boosters and a few other features, but uses a lot of Holley parts – jets, floats, valves, and so on, so parts support is excellent. I think it will work well on the Mustang, despite maybe being a little oversized – 600 CFM rather than the 500 the engine actually needs. But it was readily available, inexpensive, and gives me a little headroom in case I decide later on to swap the heads and exhaust for something that flows better.