Hi i just had a few questions about heated intake manifolds. i am planning on upgrading my slant 6 mildly with primarily bolt ons and some head work. i was wondering if the offenhauser 4bbl intake is set up to run with the stock exhaust manifold heating it. i am new to heated vs unheated manifolds but i know that for a daily driver heated is definatly more reliable on cold winter days.
thanks for the help -casey

and i think i know the answer to this but is it possible to have a heated manifold and headers? i doubt it but i was just wondering

The Offenhauser intake is equipped to run with the heat setup on the stock exhaust manifold or Dutra Duals. Headers + heated intake is no. And heated intake is not just for cold winter days, it's for pretty much all days -- see this thread (and the links from it).

(if you're talking about mild upgrades, a 2bbl is probably the better deal for you rather than a 4bbl)

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Too many people who were born on third base actually believe they've hit a triple.

thanks for the help. i would really like to run dual exhaust so the dutra duals seem perfect. and do you think a holley 390cfm is too big. i thought i could just jet it down. also where could i find some dutra duels

Unless you runs a cam capable of a lot higher rpm than stock, the engine will not pump enough air to fully utilize a 390's secondary's if at all.

See Holley carburetor sizing page, and a You Tube with a little TMI.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

I'm running a 350 cfm Holley 2bbl and even that's bordering on overkill. I would concur, a 390 cfm 4bbl wouldn't be happy on the street.

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If it was easy, everybody would be doing it.

When I warmed over my '67 Valiant I used an Offy intake, Holley 390 and a stock exhaust manifold. It worked pretty well with the stock cam, but the head had been treated to bigger valves, porting and a .080" mill. I got about 20 MPG in mostly highway driving, but didn't try to improve that. The only driveability issue was a little flat spot in the transition from the idle circuit to the mains. And that suggests that the mains were about as lean as it would tolerate. The car ran 17 flat or slightly slower at a few tracks with the manual 3-speed and 3.21 gears.

BTW, you can't "jet down" and get the air speed through the carburetor to increase. If you use high gain booster venturis you can increase the signal relative to the airflow and get an otherwise too large carburetor to work acceptably. If this doesn't make sense to you don't try it.

And the primaries of a Holley 390 are smaller than the 350 2bbl.

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Joshua

That's what I discovered after doing some reading. I used the Holley 350 cfm because I already had a manifold modified to run a Motorcraft 1.08 2 bbl carb. It really didn't take as much fiddling as I expected it would take to dial it in, just an accelerator pump cam change and a smaller discharge nozzle. The stock jets were a bit rich but out of sheer laziness I left them alone. I have stock valves but ported intakes and exhaust, Dual dutra manifolds, and a hotter ignition. Otherwise, stock.

Still, if someone is just learning about carburetors, I'd steer clear of swapping a 4bbl onto a slant.

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If it was easy, everybody would be doing it.

It is possible to have a heated intake with headers. I have a Clifford 4 bbl manifold with a heated provision cast in. Just uses coolant instead of exhaust heat.

Brian

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Flyin' Brian

74 Duster, 225, rear-mounted blow through turbo at 12psi boost, street/strip car
"Sixy Beast"

Not all do though.

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If it was easy, everybody would be doing it.

but some do. The original poster asked if he could have headers with a heated intake. All of the responses so far to his question were not mentioning that it IS possible...

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Flyin' Brian

74 Duster, 225, rear-mounted blow through turbo at 12psi boost, street/strip car
"Sixy Beast"

I am having the same question. I was thinking about welding in a bung on the header pretty close to the block and fabricating a piece of pipe that would go from the bung to under the carb to direct some exhausted gasses up that direction.

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1982 dodge w150 4 speed

Older Clifford manifolds had a pad on the bottom similar to a stock intake, but mine wasn't machined. An exhaust heat kit was offered, but you had to weld bungs into the exhaust headers to get heat. I expect I'll do something similar with my Aussiespeed intake, but I'll have to weld something to the under side of the plenum.

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Joshua

Depending on your carburetor, you can run a water heated pad. I have one for a Ford dump truck with a 292 engine that takes water from the heater hose line to heat the carb. It's not installed yet so I don't know about fuel boiling, but since it's a factory Ford piece I'll wager it's not going to be an issue. I had a set of headers that has such a heat stove as described above to heat the bottom of the manifold under the carburetor. It worked very well.

Whichever seems easiest and most effective is what I'd use. But by all means use some sort of heat if you drive in the cold.

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If it was easy, everybody would be doing it.