Can i put 72/73 fuel tank onto a 74 satellite

So the 72/73 fuel tank (cr10b) is 1/3 - 1/4 the price of the 74. (cr21a)

Visible differences comparing 72/73 to a 74: 4 vents instead of 1 and flat top of tank vs hump top.

Apparently engine size doesnt alter anything...i tried every variation and all engine sizes in the respective years were the same tank for that year on the parts websites.

I have a 74. Can i put the 72/73 tank on. I have seen a couple threads on this but there is no straight answer. The void under my trunk where the hump goes would just sit empty and the flat top would cover the void... that's my theory. Has anyone done this?
I'm going to roll the dice in the next 48hrs...unless I hear it's a no-go.

THANKS!!!

Dimensions are different, 73 tank is smaller, both in width and length, plus height it shorter. Because of the width and length differences your straps for the 74 tank may not allow you to snug the tank into place as well and they may not line up with the indentations on the 73 tank. Not 100% sure, but my motto is unless you know for certain that something is interchangeable, get the correct parts for your car.

Are you 100% sure about diff length and width?

I have 73 and 74 straps and they look identical.

The listed dimensions of the tanks in terms of depth and width are almost the same. Only the height differs due to the 74 having the hump.

72/73 flat top:
Capacity: 20 Gallons/76 Liters
Dimensions: 28-1/4 X 25-1/8 X 9-1/2 inches

74 with hump: 30 in. x 26-1/2 in. x 12-3/4 in.

72/73 https://www.1aauto.com/1972-73-fuel-tank/i/1afgt00071?f=346923&y=1973

74 https://www.partsgeek.com/catalog/1974/plymouth/satellite/fuel_delivery/fuel_tank.html

I put a different Spectra gas tank in my 77 Cordoba. If I recall it was a 73 or 74. The difference between the 2 was similar to your circumstance. My original one had a hump and was large capacity. The one I put in had no hump and lower capacity and would accomodate my dual exhaust. It fit fine. The issues you need to look at are the straps line up and the fuel neck lines up. I bought new straps but they didn't fit so I reused my old ones. I got the tank from Rock Auto. Replace the sending unit or at least the sock on it. Being Canadian made you'd think it would be better priced here. But no....

...and the repro sending unit lock rings SUCK.

thinner material than OEM which causes them to deform and come loose.

There was a FxBO member selling OEM rings a while back.

DO NOT toss your OEM lock ring if you have one.

barbiebandit said:

The listed dimensions of the tanks in terms of depth and width are almost the same. Only the height differs due to the 74 having the hump.

72/73 flat top:
Capacity: 20 Gallons/76 Liters
Dimensions: 28-1/4 X 25-1/8 X 9-1/2 inches

74 with hump: 30 in. x 26-1/2 in. x 12-3/4 in.

72/73 https://www.1aauto.com/1972-73-fuel-tank/i/1afgt00071?f=346923&y=1973

74 https://www.partsgeek.com/catalog/1974/plymouth/satellite/fuel_delivery/fuel_tank.html

Click to expand...

I wouldn't call 1-3/4 width and 1-3/8 length differences almost the same, maybe a 1/4 or less difference you could say that.

Note that those are two different sources.

Does someone personally have one of each?

The profile of these tanks is also almost the same as an M body.

Again, the straps are almost identical except the J bolt goes in the other end.

There is a lot of room/play in the strap/j bolt/anchor area.

it may well accommodate a 2 inch difference in front to back length.

YY1 said:

Note that those are two different sources.

Does someone personally have one of each?

The profile of these tanks is also almost the same as an M body.

Again, the straps are almost identical except the J bolt goes in the other end.

There is a lot of room/play in the strap/j bolt/anchor area.

it may well accommodate a 2 inch difference in front to back length.

Click to expand...

I just would prefer not to pay CAD$600+ for a tank (someone even quoted me over $1K) when I could pay less than CAD$200 with a small bit of fiddling.

I called Spectra directly and they obviously wouldn't say that you can interchange... they did confirm however that the dimensions are different as I'd noted in my original post.

Here is same source for both tanks confirming dimension difference:
https://www.partsgeek.com/catalog/1973/plymouth/satellite/fuel_delivery/fuel_tank.html

https://www.partsgeek.com/catalog/1974/plymouth/satellite/fuel_delivery/fuel_tank.html

YY1 said:

...and the repro sending unit lock rings SUCK.

thinner material than OEM which causes them to deform and come loose.

There was a FxBO member selling OEM rings a while back.

DO NOT toss your OEM lock ring if you have one.

Click to expand...

Yes I read this in a previous thread. Luckily I still have the OEM - though it's looking pretty rusty...I will try it.

slepr1 said:

I put a different Spectra gas tank in my 77 Cordoba. If I recall it was a 73 or 74. The difference between the 2 was similar to your circumstance. My original one had a hump and was large capacity. The one I put in had no hump and lower capacity and would accomodate my dual exhaust. It fit fine. The issues you need to look at are the straps line up and the fuel neck lines up. I bought new straps but they didn't fit so I reused my old ones. I got the tank from Rock Auto. Replace the sending unit or at least the sock on it. Being Canadian made you'd think it would be better priced here. But no....

Click to expand...

I found this useful thread...Cordoba tank discussion.
https://www.forbbodiesonly.com/moparforum/threads/1978-cordoba-gas-tank-interchange.37769/

The magic part of that thread is from "Kernel Sanders" (coincidentally located in my city) that replaced the CR21A with the CR10B in his 74 Satellite. However, he changed the trunk floor (to remove the cavity?) to a flat one. Not sure if this will cause me issues. I will PM him about his 10 year old post LOL.

RockAuto has the 74 tank listed for $266 US. Just make sure they send you the correct tank, just went rounds trying to get the correct one for a C-Body and they sent two that weren't even close, but that was from PartsGeek!

Also, you might want to find out if its an issue with the float on the sending unit, being a different tank, it may read erroneously with a different dimension tank.

idrivemopar said:

RockAuto has the 74 tank listed for $266 US. Just make sure they send you the correct tank, just went rounds trying to get the correct one for a C-Body and they sent two that weren't even close, but that was from PartsGeek!

Also, you might want to find out if its an issue with the float on the sending unit, being a different tank, it may read erroneously with a different dimension tank.

Click to expand...

Thanks, I went ahead and ordered the correct part. I figured the extra few bucks was not worth potential headaches ... like will my gas guage read properly etc.

Good choice, and now you wont risk a concussion whilst banging your head against the wall if the other one didn't work! Let us know how it works out.

And now the next question is paint the tank or or no? I like the naked tank look, so inclined to leave as is if it will last or maybe clearcoat (with what I'm not sure). Did research and came up with this so far...for science and posterity.

from British V8 Magazine article:
"Spectra Premium Industries' .... fuel tanks are made in Canada from U.S. Steel's "Ni-Terne" material. The annealed cold-rolled steel sheet is first processed to apply a thin flash coating of electrodeposited nickel, and then it's given a hot-dip lead-tin alloy coating. The nickel base coat gives Ni-Terne steel an extra measure of corrosion resistance compared to U.S. Steel's regular "Terne" steel sheet and also compared to traditional galvanizing, which isn't readily available anymore. It should also be pointed out that the Ni-Terne coating protects both interior and exterior surfaces of the fuel tank from surface corrosion.
...
Painting the Spectra Premium fuel tanks isn't required or even recommended. If you wish to paint one of these tanks, you'll need to clean it very carefully to remove an oily film, and then scuff it all over. Per Kelvin Dodd at Moss Motors, for best adhesion you really should chemically etch the tank before painting"

Then I read in a further post thread:

"Painting

Terne sheet and NI-TERNE sheet can be readily painted by either continuous coil line prepainting or post-fabrication spray-painting techniques. The excellent paint-adherence characteristics of the lead-alloy surface allow painting with conventional materials, equipment and systems.

Many types of paint are compatible with the terne-metal surface for painting after fabrication. Often, no primer or pretreatment is needed. Only the usual removal of dirt, oil, grease or other contaminants is required. When U. S. Steel Terne Sheet or U. S. Steel NI-TERNE Sheet is to be painted, it should not be ordered with a chemically treated surface unless tests are conducted to confirm that the chemical treatment does not adversely affect the paint adhesion. It should be ordered dry or with oil only.

Source:- http://www.ussteel.com/corp/sheet/coated/ternefc.htm
"
One opinion in that thread was:

"Unless its high-grade stainless steel or titanium I wouldn't recommend leaving any tank unpainted.

I agree with either the por-15 or a few coats of spray-on bed liner. You can paint over either of those. The por-15 needs to be painted because it will break down quickly if exposed to UV light but, hopefully, your tank wont spend too much time facing the sun smiling smiley

I wouldn't do the inside-the-tank coatings, however. That stuff sometimes breaks loose and clogs up your lines and carbs. the gas in the tank will keep the inside of the tank pretty rust free, especially if you keep it on the full side."

Then in another thread:

"Bruzilla, if your new tank is a Spectra it should be weather proof. It may look like bare metal, but it is ni-terne coated. Which means that it was given a flash coat of electroplate nickel, then a tin/lead alloy dip just like the original."

And same user commented in different thread:
"Spectra tanks are ni-terne coated which is a coating of about 92% lead and 8% tin. This coating has excellent corrosion resistance for fuel tanks."

Another thread:
"...Zinc is the standard or base model. It is zinc coated inside and out for corrosion resistance and is a good value for the money.

Ni-Terne - The next step up is the Ni-Terne tank also know as "tin sheet" which is a special material that is manufactured in Japan.
Ni-terne is generally accepted in the industry as the material that is closest in appearance and corrosion resistance to the original OEM tanks that came from the factory.

Stainless Steel tanks offer superior corrosion resistance, and a more upscale or custom appearance."

And to add more fuel to the fire there's a whole thread on tank painting in general, though not Ni-terne specific...with varied opinions.

Sooo...that was too much info and now I'm well down the rat hole of a seemingly religious debate.

For science: Has anyone had a Ni-terne fuel tank from Spectra that they left naked and has been installed for over 3 years? If yes... what is the result? Please answer in this new separate thread: https://www.forbbodiesonly.com/mopa...led-spectra-fuel-tank-naked-unpainted.172553/