Opinions requested

Hello community!

I am at a decision point during the restoration of my Classic Eliminator (1 of 3, I am told). The conundrum lies in the emissions system that California mandated that the car must have back in 1970. Since then, the air pump, exhaust pipings, etc. have been removed and probably discarded. The gas tank, however, still has the old California emissions plumbing and hoses. I have decided against using the original tank as it sat open for years and has rust inside. I have the old tank sitting apart from the car and underneath the original undercoating is the original metal finish with some over-spray (competition yellow) intact. Should I keep all of the emissions junk as is (just cleaned up a bit) or can I remove the piping and plumbing in the trunk without destroying some of the uniqueness of this car? I have a new tank but it does not have the emissions vent on the driver’s side vent forward on the tank. I can keep all of the old stuff for a future owner but I’d like to get an opinion on using the original tank.

Thanks in advance,

I faced the same dilemma on my CA Cougar. I restored all the emissions parts planning to keep it original, and tried to get by with the old emissions tank for several years. But the inside was really rusty and the sediment kept plugging up the carburetor. It’s amazing the amount of fine sediment that gets through the fuel filter. So I ended up replacing the tank and changing to the vented fuel filler tube and cap. Finally able to drive it without fear of carb plugging up and stranding me! To me, that is worth a lot more than that old rusty tank was worth. Also noticed rusty sediment being sucked out from the charcoal canister was accumulating in the air cleaner base, so I plugged it too. The emissions stuff is all still there so it looks original, just no longer functional.

My 1st reaction is to make it all functional if you are into originality, and relegate it to a box in the garage if you are not. I didn’t realize the CA fuel tank, charcoal cannister, etc. is so difficult to source/restore, so Craig’s approach sounds good too.

My 70 has the evap system… has anyone ever cut the top half off an evap style tank below the seam and basically installed it (like a cap) on top of a standard tank? This would give an original appearance inside the trunk and allow the evap hose assembly In the trunk to be installed. Working out the filler neck might be an issue tho

Most of the top seals on that 1970 emissions system that I have encountered have shrunk and leak fumes really bad. The system could be sealed maybe, how functional, I don’t know.
Marcus Anghel, has an article that explains and shows a cut away view of the top of that tank.
Splitting the tank open and cleaning around the vent system may be a challenge.

A person could just drop in a 1969 20 gallon tank and filler neck, and lay the octopus of tubing on top of the tank under the matt. Unless someone knows about the emissions filler neck rubber tube and filler neck differences. Probably go unnoticed by all but the most hard core enthusiasts.
I would plug those lines though.

Thirdly, scrap it all, buy the 22 gallon tank with filler neck and act like it never happened.

Chuck, do you still have the distributor modulator system? That is an M code thing in 1970.

Scott, Chuck’s car is a 428 / 4 speed. IIRC the Distributor Modulator System is a 1970 M code Auto only thing.

Mine is an M code and I did get the original distributor modulator system working. But I got tired of it not letting me have vacuum advance at low speeds and have since bypassed it. Agree with Scott on all the seals, tubes, and vapor separators associated with emissions tank leaking fuel vapor into trunk. I was able to find a repro 22 gallon tank that had the stamped top to accommodate the vent assembly without the hole for it. So I JB Welded the bolts to hold the vent assembly on top of the tank. Then I capped all the vent tubes inside the vent assembly with vacuum port plugs. Only way you can tell it’s not original is the different filler tube, lack of rubber seal where it enters tank, and the vented fuel cap. Probably not good enough for a concours judge, but like Scott said, not many others even notice.

Since the tank is so rare I would keep it and send it to one of those restoration places to get the tank clean and resealed. I imagine it wouldn’t be much more than getting a new tank and since thes are likely less that 100 left it would be good to try to keep it as original as possible. Just my thought

Keep in mind that besides just your gas tank, there are the plastic vent assemblies in the driver’s side trunk area, as well as a check valve mounted to the frame along the rear driver’s wheel. Then you have a metal vent line that runs from the trunk up to the engine bay, with some rubber line that goes to the charcoal canister, followed by a paper tube up to the air cleaner.

If it were me, I would swap to a new gas tank but leave as much of the rest of it in place as you can. It’s been on the car for 50 years, you might as well just “store” the parts on the car. You’ll have to disconnect some of the plastic tubing that goes to the vent assembly that connects to the original gas tank, but that shouldn’t be a big deal.

With the new gas tank you’ll need a different filler neck and tube for connecting the neck to the tank, was well as connecting hardware and gas cap, but then you should be good to go.

Store the original gas tank and filler neck, and connector hose and hardware, if you have the room to do so. They aren’t making any more of them, and a future owner might appreciate it. If you can’t store it then list them for sale - chances are someone will be willing to pay for them.

That’s just my opinion on it, and probably what I would have done if my CA emissions tank had been rusty.

OH! Be sure to replace your fuel line too, while you’re at it. It will almost certainly have rusted on the inside and will clog up your filter and carb, like Calicat mentioned.

Thanks Mike. I have a new 22 gallon tank from Tanks, Inc. still in the box. I also have the old tank pick-up assembly with the low fuel sensor intact. I like the idea of leaving all of the “plumbing” in the car, except for the tank, and storing it in the car. The tank can live on the shelf at my shop for a while. I have new fuel lines as well as brake lines (stainless) to be installed when I get the car back from paint and body.

Chuck, you can have your low fuel sending unit restored by Bill Basore. He does great work!


Another thought is that you could modify the emissions tank vent assembly where it connects to the top of the gas tank. Remove the stuff that would connect to the internals and just lay that connector assembly on top of the tank (glue it or putty it in place maybe). That would give you the appearance of a proper Evaporative Emissions system, without the hassle of worrying about the tank.

Of course a keen eye would spot that different filler tube and rubber connect to the tank… Not sure if you could fit the emissions tank rubber connector over top of the regular rubber connect, but it’s something else to consider if you want it to appear closer to correct / original.

Here is another question! After having the underbody and engine bay pressure washed, there are places where the original sound-deadener has come free and other places where it is still attached. Would it be better to remove ALL of the sound deadener and finish the underside in satin black or patch the missing pieces of deadener and then finish in satin black?

I’m curious because the original Competition yellow overspray is visible where the sound deadener has flaked off. With all of the non-concours parts on this car, I’m wondering if concours finish underneath is worth the effort. I suppose that I can do that part now and then finish the concours completion over the next few years, or the next owner can…

If you plan to drive it a bunch and aren’t showing it for “points” type of judging, then I’d say just strip it and spray it in some sort of very dark slate / black-ish color to somewhat replicate the original “slop gray” that the factory used. That should be good enough. You can add other details to the underside in the future, but it can be tough.

Is there a specific color assigned to the underside paint? My paint guy can match anything with nothing (but not for free).


My two cents is it’s probably not worth worrying about getting all the proper colors restored underneath unless you are doing a concours restoration and not going to drive it. Mine had been undercoated when new, and like yours I found the original paint overspray, color stripes, etc intact underneath the undercoating. I decided to just preserve it in that state. So I wire brushed off all the loose undercoating, cleaned it up really well, and reapplied a light coat of 3m rubberized undercoating on floor pans, torque boxes, under fenders and wheel buckets, and around rear subframe while the gas tank was out. I masked off or removed all splash shields, hardware, springs, wires, tubing, etc first so undercoating just got applied to intended surfaces. Since mine gets driven, I figured the undercoating provides a bit more moisture protection in case I splash through a puddle anyway.

The undersides of cars built at Dearborn when yours was built were painted with “batch” color. Whatever paint was left over from painting the exterior of cars was dumped into the mix every day, resulting in infinite shades and infinite amounts (or lack) of metallic.

There is no right answer other than telling the painter to touch up what’s there as best he can.

[quote=“, post:16, topic:13702”]
The undersides of cars built at Dearborn when yours was built were painted with “batch” color. Whatever paint was left over from painting the exterior of cars was dumped into the mix every day, resulting in infinite shades and infinite amounts (or lack) of metallic.

There is no right answer other than telling the painter to touch up what’s there as best he can.


I found the batch color underneath mine too. Kind if a reddish beige, but I suspect the red was the primer showing through a very thin and poorly applied coat of the batch paint.

No there isn’t a specific color and for 70 it really depended on what the majority of the cars were painted (exterior colors) in the time period just prior to when you car was built so look to others built as close to your car for guidance. There were some short periods at that plant that year where it appears, through examples, that red oxide epoxy was used. By 70 there were allot more pastels, and bright colors offered and this affected the left over paint colors that were added to the base for the floor section/undercarriage of the car so the range of possible colors appears much larger than in 69 for example. SOme of them didn’t go very well with the exterior color overspray while others were almost a match.

If I was making the effort to clean and paint the undercarriage of a car today I would choose to reproduce the factory colors as close as possible. If you go with generic black or red oxide you limit your choices going forward. Its not like you’ll be repainting the floors and frame if you choose to do more of a restoration later - consider that everything after paint and body work is a bolt on or off item that can change with your possible changes.

Firewall forward (front frame and wheel wells) were painted at a different station than the floor and can differ depending on when the car was built during the production year

Just something to consider. Good luck with your choice

So I am having the engine compartment (dog house?) painted a “satin” black. Much less than gloss black but much more than flat black. Going with undercoating to replicate the way it was when I got possession of it in 1970 (minus the gobs of overspray on discreet underbody parts).