Gas to Diesel swap, question on fueling

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

idrivea2002golf

Junior Member
Joined
Feb 19, 2025
Posts
18
Reaction score
28
Location
San Diego
First Name
Spencer
Truck Year
1981
Truck Model
C20
Engine Size
Not sure yet.
I'm reaching to the forum for recommendations/feedback/thoughts on fueling systems. I've been on the different square body forums looking up the function of the dual tank and the Pollack valve. Seems pretty straight forward. I don't like that it relies on the suction from the engine's mechanical pump for priming, I'd like to have a more proactive fuel supply. For reference truck is a 1981 so I have the 6 port with the motorized valve. I'm currently planning on swapping in a 7.3 idi out of a 90 F350.

Here's where I'm looking for feedback, as I see it I have two options:

Option 1: I keep the existing system as it is (obviously check for functionality and replace anything broken). Use the ON-OFF-ON momentary on the dash for the switching as it already does. In this case I would add an in-line fuel pump (diesel style) between the Pollack valve and the engine's mechanical pump. This would tie into the ignition system. Simplest option but I know these pumps make noise and I don't know if I'm going to want to hear it all the time. Chineseum pumps are 20-30$, Holley or AEM are 200ish.

Option 2: swap the fuel senders I currently have (1981 models) with senders/pumps from 1987+ and basically run two in tank pumps through the Pollack valve. This would require I swap the dash switch which isn't all that difficult. I like that this gives me pump redundancy as the in-line pumps can be fickle. Obviously more up front cost but really not terrible in the grand scope of this build. From my understanding the wiring is the same between the 1981-1986 and 1987+ at the valve, just need to tie in the sending pumps power lines. This also gives me the flow/pressure required for a diesel as I can get the 6.2 in tank pumps. Each pump is about 110$ on rockauto. So similar price to a quality (Holley) inline.

Option 3: something I'm not seeing?
 

ali_c20

Full Access Member
Joined
Sep 20, 2016
Posts
1,473
Reaction score
2,108
Location
Austria
First Name
Alexander
Truck Year
1974, 1979
Truck Model
C20, K5
Engine Size
350, 350

Frankenchevy

Proverbs 16:18
Joined
Jan 3, 2018
Posts
6,182
Reaction score
7,991
Location
USA
First Name
Jeremy
Truck Year
Square
Truck Model
CUCV
Engine Size
Small
Also, 87+ also have baffled tanks to go with the in tank pump. May not matter, but something to consider.
 

Latest posts

Forum statistics

Threads
44,943
Posts
971,796
Members
37,814
Latest member
olddirtybitch
Top