Ideas for DIY Air Intake Plenum for Early 70's Ford 302 V8?

My early 70’s Ford truck’s intake plenum disintegrated several years ago. It is a sort of 2 inch x 4 inch (in cross section) rectangular shaped rubberized tube which goes between the front grill area to the air-cleaner intake. Used to route fresh air into the engine. I constructed a “temporary” replacement out of duct tape. But I’d like a more permanent sol’n. I’ve asked at my auto parts store, and looked on web site like Rock Auto, haven’t found an aftermarket replacement. Any ideas how I could make one myself?

The duct tape version is too flimsy, tends to collapse. And it isn’t very tolerant of the heat inside the engine compartment. My current thinking is to use some cardboard, the type like from a pizza box, that kind of cardboard, fold it into the proper rectangular shape, then to stiffen it up and make it more durable, wrap it with 3 or 4 layers of aluminum metalized tape, the kind of tape like if you were wrapping the heating ducts in your house.

It’s been years since I’ve seen aftermarket replacement for the fresh air ducts like that, but they used to be around. Perhaps one of the “old-fashioned” (not AutoZone) parts houses around may still have some in some dusty corner somewhere.

Are you convinced you need it? Do you need to pass smog with that truck? I suppose if the weather were hot enough you might notice some slight difference, but I’m betting your truck will run perfectly well without it.

I bet there would be very little change without it…


Let me ask you a question?

Why do you keep referring to your vehicles as an early 90"s Toyota or an early 90’s Ford?

Did you ever think that if you gave the exact year that you could get more information on the vehicles?

As any mechanic knows, you need the make/model/ and YEAR!


Red Green would be proud of you… :slight_smile:
Perhaps you could fashion a replacement out of convoluted aluminum ducting from the hardware store.

You could convert it to a K&N air filter which replaces the whole thing.

A Red Green sol’n? I can see that. After all, my all-time favorite TV character is Ernest T Bass … lol …

Thanks to all, I think I’ll take a visit to the local home hardware products store for a look-see. Maybe some of that thin flexible metal ducting for venting clothes dryers-- with a little adaptation for fitting the two interfaces – would fit the bill. There’s a good local “non-chain” auto parts shop I use sometimes when I can’t find the part at the chain stores, I had to use that place when my accelerator pump starting leaking, so I’ll check there. And I’ll look into the aftermarket air filter ass’y such as K&N idea too. Doing without, simply let the air intake come from the air inside the engine compartment? This engine has a tendency to overheat on 4WD slow climbs so I’d prefer to keep the air intake as cool as possible.


Or 4" aluminum clothes dryer vent hose.

That’s what it looks like Tester, but some trouble about availability noted. Says it is not available at the store, and not available for shipment to the store. I’ll check in w/my local autozone store, see if they can help. I didn’t see anything like this on RockAuto. Thanks for taking time to post the autozone link.

Yes Keith, that was what I was thinking, aluminum dryer vent hose might work.

Try If they don’t list it, it probably doesn’t exist.

Yup, LMC Truck has it. $25-$33. Too cheap to consider a hap-hazard DIY.

Thanks for the link BK, if the local Autozone can’t get me one I’ll phone up LMC and get one on order from them.

Is the other duct also in good shape? The round one to the exhaust manifold often ends up missing.

Good point Texases. Yeah, the original exhaust intake heat riser tube bit the dust too, but I replaced it already. Several years ago. As I recall it wasn’t something you purchased by the vehicle’s make/model/year; instead the parts store stocked it in bulk, and you just cut off how much you needed. I think it is just flexible aluminum venting pipe. The engine definitely cold-idles better with that pipe in place. At the same time I replaced the third pipe to the air cleaner, the one from the charcoal canister. That one is weird, aluminum on the inside, and paper on the outside. I had a harder time finding that one. I’ve always wondered why they made it with that unusual combination of materials?

96052 appears to be the part number for the Dorman brand but with the exception of a vendor with the part isn’t in stock even when they list the item. Napa or a more local auto parts store might still stock something that would work but i’ve been out of that business for over a decade. The store that I worked at still stocked them but that was years ago.