[Sunroof]

On the gas tank.....the 1973.5T gas tank is one of a kind and the only way to replace it is with a new CIS tank. Their are no 1973.5T tanks that are new and for sale, unless I am missing something! The problem here is you can replace the tank with a newer CIS tank but loose using the large spare tire and have to opt for the tire saver spare and reconfigure the gas lines (out and return). BEWARE of vendors ads that have new gas tanks up to 1973. Yes, the 1973 models up to May/June used a non-CIS tank and the tank prices are reasonable; however, the CIS tank has a series of internal baffles, swirl pot, large 22MM filter and the gas lines (fittings) are configured correctly. So, good luck replacing the tank if you want originality or want to save $$$$$.
Enter: Tank Refurbishment. The gas tanks are very easy to remove. You must drain the tank (done through either syphoning or opening up that large 22MM filter in the center bottom of the tank). Do please disconnect your battery first! The two hoses on the back of the tank come off, the fuel level sender comes off, the fuel filler hose comes off as too the hose for the carbon filter. You have several options from here: Their are a few shops that will totally refurbish your tank for under $1,000.00 or you can take the tank to a radiator shop, have them "boil it" in a caustic solution as they do radiators and then coat the inside with a few proven products such as those sold by POR. POR has a tank coating. One word of caution here: DO NOT USE REDKOTE for tank coating. This is what my radiator shop used as recommended. Its an approved internal tank coating used on Navy ships and is great, BUT that swirlpot inside your tank is made of bakelite (same as the distributor caps) and it turned out REDKOTE does not adhere well to bakelite. Just trust me on this one! So take a look at the POR product line and try a thread here as many have refurbished fuel tanks using POR coatings. You can remove the outer gray thick tank coating with paint remover or metal brush down to bare metal, coat the outside with POR15 and follow up with WURTH gray coating for a factory finish. The cost of all this should be about $500 but you need to supply the labor. My refurbished tank has lasted over 10 years now with no issues.

Welcome to the Porsche 1973.5T long hood world!

Bob