73-87 sender?

[C15_Sierra]

My 1980 carb single tank has a 2 outlet sender, and I'm wondering if I would be able to use that for my upcoming LS swap? I don't think it's a return line (carbs don't have return lines?) and I read somewhere that later models with TBI have 3 outlets on the sender? Do I need to run a 3 outlet, or can I use my existing 2-outlet sender?

I'm planning on running an LS1-style filter regulator, so all I need is 1 feed and 1 return line

Thanks!

[STOCKISH]

You will want to use a sender for a 87. Since it was fuel injected from the factory it has provision for an in tank fuel pump which you will want to run. AC Delco EP381 I think is what I used. The sender in your tank wont have the provision to hook an in tank pump to and frame mounted pumps are just loud in my opinion. Good luck.

[C15_Sierra]

I'm planning on running a frame mounted pump. I'm aware it makes more noise but I prefer to make it simple

Found that the second fuel line runs to the charcoal canister in the engine compartment. Would I need to run some sort of vent if I use that second line as a return line?

I'm just trying to see if I can get away with using my 2-outlet sender for the time being

[flamingbig10]

if your mechanical fuel pump has 3 lines running off it you'll have return line
for the fuel pump I would use some thing like this
http://www.summitracing.com/parts/MS...s/?prefilter=1

[C15_Sierra]

I plan on running a Walbro GSL392 (255 lph) inline pump and Vette fuel filter/regulator.

In tearing down the front end, I discovered that the second line is a vent line to the charcoal canister up front. Is there any reason why I cannot use that outlet for my return line, or do I need a vent of some sort?

[DirtyLarry]

Originally Posted by 1972SuperCheyenne

You will want to use a sender for a 87. Since it was fuel injected from the factory it has provision for an in tank fuel pump which you will want to run. AC Delco EP381 I think is what I used. The sender in your tank wont have the provision to hook an in tank pump to and frame mounted pumps are just loud in my opinion. Good luck.

I second this notion. I ran a Walbro frame mounted pump for a few months (~500 miles) until I grew tired of the noise and dealing with fuel cavitation issues when the pump was hot. Changed to a 1987 fuel tank and sending unit along with an AC Delco EP241 fuel pump (Corvette/F-body pump) and haven’t had an issues in 2 years and 6,000 miles. If I were to build another LS or 8.1L project I wouldn’t even consider a frame mount pump. That was a waste of time and money.

[C15_Sierra]

Believe it or not, I still haven't gotten around to this. Project had to take a sideline for some other life events, but now I'm getting back to it.

Now I'm thinking I should run an 87 tank and sender, to eliminate any sort of hassles. As for fuel pump, I dunno what I should run. The EP241 that DirtyLarry mentioned is for a TPI engine which runs 45 psi, I heard the 5.3 likes 58psi...will that pump be able to supply the needed pressure?

Hmmm the EP381 might be better suited since it looks like the Vortec 350s have the same fuel psi requirements

[DirtyLarry]

Originally Posted by C15_Sierra

Believe it or not, I still haven't gotten around to this. Project had to take a sideline for some other life events, but now I'm getting back to it.

Now I'm thinking I should run an 87 tank and sender, to eliminate any sort of hassles. As for fuel pump, I dunno what I should run. The EP241 that DirtyLarry mentioned is for a TPI engine which runs 45 psi, I heard the 5.3 likes 58psi...will that pump be able to supply the needed pressure?

Hmmm the EP381 might be better suited since it looks like the Vortec 350s have the same fuel psi requirements

The pump doesn’t always determine the fuel pressure at the fuel rail although a pump is only capable of delivering a max pressure and flow rate. The fuel regulator determines fuel pressure at the fuel rail. Even though the EP241 was originally designed for TPI engines with a fuel pressure if 45 psi it will go well above 100 psi if you want to and is happy running the 8.1L in the normal operating ranges of 58-62 psi just fine (same range as a small block). Some swear by EP381’s and some swear by EP241’s. Personally, I don’t see where it matters as the pump doesn’t determine fuel rail pressure anyway as long as it can maintain the max pressure and flow rate when you plant your foot to the wood, which both seem to do just fine. I suppose if you are getting crazy with big injectors, etc the EP381 would be the better choice as it does have a slightly higher flow rate and capabile of delivering higher pressures if required. Then again, if you push too much pressure at the fuel regulator you run the chance of running rich with a high idle, hard starts and horrible fuel economy. Been through that one already with a L29 project.

When my EP241 dies I might try a EP381 just to see what it is all about. Who knows, might not even be a noticeable difference in a stock engine. There is only a $10 difference between the two pumps through Summit with the EP381 being the more expensive one.

[C15_Sierra]

Thanks! Any problems in keeping my stock tank? I thought the only difference were the baffles to keep fuel in the vicinity of the inlet, but I've never seen the inside of an 87 tank.

I'm assuming if I keep my stock carb tank I'll have to keep the level above 1/4 or so (which I do in my cars anyway)

[DirtyLarry]

You know, I am not sure what exactly the difference is with the ’87 tanks. I thought the hole where the sender went in was a bit bigger. I used a new ’87 tank when I did the ’87 sending unit.

[DirtyLarry]

I just found a picture of the ’87 tank and ’87 sending unit as I was getting ready to bolt it in. Not sure if you can see any differences between an EFI tank and carb tank in these pictures or not…..but this is what it looks like. Mine has one extra hose connected to it that comes from the RH tank to transfer fuel to the LH tank. The stock Pollock fuel transfer switch is too restrictive to use on the return side when running high Vortec size EFI fuel pressures.




This is the transfer pump I am talking about… mute point if you have a single tank. I kept the switch tank valve only to be able to see how much fuel is in the RH tank. All ports are capped off.

[CamaroChris]

I just received my 87-91 sending unit from rockauto.com today. It was 63$ the WIK corvette filter was 32$ For my fuel bump I just jumped on summit and found a walbro/edelbrock fuel pump GS340 I think. Any way it was made to fit this sending unit for a edelbrock after market injection system on the TBI motors http://www.summitracing.com/parts/EDL-3581/ I mean the pump is not different but the wiring is for direct plug in to the sender

[C15_Sierra]

Thanks Chris! I keep forgetting about RockAuto when I search for parts - I need to keep them in mind - $63 for a new sender ain't bad! I'm going to have to find a different filter, since my engine is a return-style fuel rail (has the regulator on the rail so I need to plumb two lines), but thanks!