Hey Guys,

Looking to replace fuel tank on my 70' Cutlass Supreme. It's a stock 350 and this is the original tank. The trunk pan is rusted out so I'm going to have that done first then tank swap. How can I tell what tank I need? YearOne and OPGI sell tanks that are either 2 vent or 3 vent for EEC/ECS and non-EEC/ECS setups. I haven't noticed a charcoal canister or evap canister anywhere so I'm not sure as to what was factory correct for the 70' CS. Any ideas?

 

The number of lines has nothing to do with the fuel tank - it's the sender. Check your fuel pump and see if it has 2 lines (main & return) in addition to the one to the carb. That will tell you what sender to get. I bought mine from ILT.

I like the Spectra Premium tanks. The one for your 1970 is likely a GM34Q. Check Rockauto and use 1970 Cutlass 5.7 in the drill down menu. Then Fuel/air.

 

did you use the gm34Q for the supreme. Just want to confirm it is the same. I assuem a Cutlass tank is the same for supreme...

 

My car is a 1972 model,year so I had to replace with GM34R and it's a perfect fit. I looked up your tank to get that reference number. It will be the same for all 1970 Cutlass models.

 

The evap lines DO have something to do with the tank. The sender lines are on the sender, so the tank doesn't matter.

Del70, get under your car and look at how many lines are coming out of your tank along the top front edge.
There's absolutely the fuel line.
There are 2 or 3 vent lines.
There may be a fuel return line (I've no idea what years/models had them, sadly).

Then just get the right Spectra part from any resller. Good quality stuff.

 

x2 on Rock Auto. By far the cheapest I found.

 

According to the 1970 CSM the tanks are identical. The only difference is what sender unit is used (SW which is a different tank anyway)

droptopron - check out this link: On Amazon for 138.00 and Free Shipping!

 

thanks, already knew how many vent lines I have. Just wanted to confirm if the Cutlass and Cutlass supreme used the same tanks, which I was pretty sure they were the same less potential vent qty .... tank is on order, all set. thanks

 

I bought mine from Impala Bob's on ebay. It was a lot cheaper than the rest. Great customer service

 

I got my Spectra tank from Amazon with the free shipping and it was a perfect fit. I did order the correct model one for a 68 not a 70, but I image they will all be correct if you get the right one. It was at my door in less then a week after ordering.