Tbi swap build thread

[rfmaster]

Originally Posted by mocajoes

Wow that is a vast amount of information thank you again. I am glag to hear that it will work. Yes I am going to use a th350 tranny so I will be trying to decide the best way to go. I had to go out of town till Saturday so I will try to catch back up then. First things first I need to get the old engine out and get the new one in. Not sure how to address the fuel tank. I have the factory 94 tank with pump in it but, it seems way too big to fit under my truck and Im pretty sure the original behind the seat wont work as there are no return lines and no vent line. Thank you for the great in depth info be back soon.
Brian

Brian
You may want to replace that 'original' gas tank any way. After 41 years in service a steel tank probably has bunch of crud and rust accumulated in the bottom. I am not familiar with 70 SWB gas tanks first hand, but from a quick catalog search it would appear that there are two tanks available - non EEC and EEC tanks. The EEC stands for Evaparotive Emission Control - simply put charcoal canister purge (CCP) is used to capture gas fumes and burn them in the engine instead of being lost into atmosphere. This is system costs nothing in terms of engine performance, but it keeps HC's from escaping into the air. The EEC tank probably has 1/4" CCP line which is too small for fuel return, but you better have it since EFI fuel circulation heats up fuel in the gas tank increasing fuel vapor pressure - EEC Hollander 869, GM 6272124, GM49B. To plumb return line you'll have to tap into filler neck with 5/16" barb - use external fuel pump and 3/8" fuel line for fuel supply.

//RF