Dual Tank Sending Units -EFI Swap (85-87)

[SquareRoot]

I'm converting my 85 to 87 for my efi. Purchased D/S (Main) tank and sending unit. It appears the P/S (Aux) sending unit remains impossible to find. I read in the description on one of the sites that the difference was which way the outlet hose barbs are pointing and that may be why they are not interchangeable?

So they question becomes, if the hose barbs are made (whatever means) to point inward (away from the frame) would it work on the P/S? I have no problem with fabrication skills.

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[Doppleganger]

I had no trouble getting both sending units....think I got them on Carid, parts daddy or one of those online places. I'll see if the invoice isn't still in the box. They were Spectrums made in Canada.

I found the GOOD in tank pumps (AC Delco's made in Brazil, not china) at Autozone of all places. I -may- have gotten the sending unit there too. Dunno.

 

[Bextreme04]

@Vbb199 ran into this issue with his truck. He managed to get the passenger side sending unit from LMC I think. The issue is in how the units are described as the "Main tank" and "Aux tank" as they were on different sides depending on the year range.

 

[Vbb199]

Yes, my 79 c10 shortbox's pass side tank was called the aux i do believe.

I think it was the tanks are the same, sending units are different.

Or maybe its backwards, all i know is, LMC didnt have anymore pass side tanks, and i bought the last one from rock auto for a c10 shorty

 

[SquareRoot]

I had no trouble getting both sending units....think I got them on Carid, parts daddy or one of those online places. I'll see if the invoice isn't still in the box. They were Spectrums made in Canada.

I found the GOOD in tank pumps (AC Delco's made in Brazil, not china) at Autozone of all places. I -may- have gotten the sending unit there too. Dunno.

More info please! And don't be like @Vbb199 and tell me you bought the last one.

 

[Doppleganger]

More info please! And don't be like @Vbb199 and tell me you bought the last one.

https://www.autozone.com/fuel-deliv...-unit/p/delphi-fuel-pump-dhp10256/1114075_0_0

 

[Scott91370]

I may be off base on this so correct me if I am wrong. I hope I am not because in the future I'd like to switch myself.

You're using the factory pre 87 tanks with 87 sending units to run dual tanks and fuel injection?

 

[Bextreme04]

I may be off base on this so correct me if I am wrong. I hope I am not because in the future I'd like to switch myself.

You're using the factory pre 87 tanks with 87 sending units to run dual tanks and fuel injection?

You can do that, but there is a risk of the pumps running dry when there is still fuel in the tank. Most people switch to the EFI tanks(87 or later), or cut the tanks open and create their own baffles, or use an aftermarket sump/baffle system.

I'm personally converting to a 31 Gallon EFI Blazer tank for mine. The simplest conversion from a "need to fabricate custom parts" perspective is to use a complete 1987 truck fuel system. I needed to go with the blazer tank due to needing to move the forward rear spring mounts forward 4".

 

[Scott91370]

You can do that...

That's great info. I didn't realize you could use the 87+ tanks (even though they are for EFI) when doing the swap.

Thanks!

 

[SquareRoot]

That's great info. I didn't realize you could use the 87+ tanks (even though they are for EFI) when doing the swap.

Thanks!

87 is the ONLY tanks that are the same as all previous years EXCEPT the 87 has built in baffles to help prevent fuel starvation on inclines, braking, etc. TBI came out in 87. They added the baffles and 88 and later are completely different altogether.

 

[SquareRoot]

That's great info. I didn't realize you could use the 87+ tanks (even though they are for EFI) when doing the swap.

Thanks!

It's not "87+", it's 87 only.

 

[Scott91370]

It's not "87+", it's 87 only.

87 is the ONLY tanks that are the same as all previous years EXCEPT the 87 has built in baffles to help prevent fuel starvation on inclines, braking, etc. TBI came out in 87. They added the baffles and 88 and later are completely different altogether.

OK, I said 87+ because the post a couple up from mine said it. But since they body style changed in 88 that makes sense.


Edit: Didn't realize both posts were by SquareRoot

 

[HOTFOOT]

87 tanks are what I put in my 80 k3500 with carb sending units because I may put a 95 lt1 in because I have 3 of them or trying to get a 8.1 to use. Had to move the float a little to clear the sump.

 

[Bextreme04]

Didn't the 88-91 Crew Cabs have the baffled EFI saddle tanks?

 

[Doppleganger]

The tanks (in spite of their size) are still pretty cheap....delivered. It was going to be $135 ea with shipping but I found Autozone carries Spectra, so got them there on sale for around $90 (with tax) each and just picked them up at the store for nada.

Just pay attention to the PN when/if you order one. Its literally something like 12345 vs 12345b.