Hey guys i have an 86 iroc that came with a mechanical fuel pump.
I want to swap out the junk 305 and put in a 5.7 most likely will go with a vortec 96-99 block but what holds me back is the fuel pump.

I will need to go electric for a newer block regardless of what route i decide to go.(plan on keeping car carbed)

How hard will it be to rig up? What will happen with the mech pump? Can i leave it in? Or will i need a block off plate?

I know ill be needing a regulator.

I want to go with an aeromotive pump, i heard they are really good quality. Which one could i run safely in a daily driver without burning up the pump?suggestions on a pump would be great.

Any info appreciated thanks guys

 

A block off plate is used to close the hole in the block left when you don't run a mechanical pump. If you're using a later block that doesn't have the pump push rod or drain back holes drilled, you don't need a block off plate.

The mechanical pump goes away.

I used an Aeromotive pump on the '57 when I was running E85 and nitrous (about the equivalent of 600 HP with gasoline). A little noisy mounted on the frame, but it handled both street & track with no issues. It's a little large, but if you can find a place back by the tank/axle to mount it, it'll work fine. I just used a cheap Holley dead-head regulator. Pretty sure it would be louder in a 3rd gen that it was on the '57.

For the LS1 swap into a factory-carb'd '82, I just swapped a TGO member for their EFI tank pick-up and put a Walbro 255 pump in it. In your case, you'd also need a return-style regulator like a Mallory 4309 to lower the outlet pressure to a carb friendly 4-6 psi. I like the in-tank setup better, as it's quieter. It for sure will put out plenty of volume to supply your 350.

 

Thanks for the reply five7.

Im not sure if ill be doing the engine swap and fuel pump all at once which is why i asked about the pump block off in case i run the pump on the 305 a while. Would the block off be needed then?

To sum it up u suggest the walbro 255, efi tank pick up (what does the pick up do exactly?)and a mallory 4309 regulator?(or would i need both the holley and mallory?)

Which aeromotive did you go with on the 57? I researched them a bit and if i go with them id like to find one thats streetable.

As far as the mounting location, would it be better mounting it on the exterior for easy access ? (assuming sound isnt an issue)


Sorry to ambush u with questions, i appreciate the info.

 

If you do the electric before the engine swap, you could use it as a pusher to the mechanical pump. If you have a stock mechanical pump with the return line, you wouldn't need a regulator. That is a somewhat controversial position, though. If you bypass the mechanical pump and go ahead with the regulator, you could remove the push rod and just put the pump back on instead of buying a plate you won't use again.

The tank pickup is a combination of the fuel lines and fuel gauge float/sender. I thought I had a pic of the carb'd version, but I'm drawing a blank. Basically, it sits on the top of the fuel tank with a flanged connection, with the tubes and wires coming out of it. The EFI version has mounting provisions for the electric pump. The electrical connectors are different between the two, so you'll have to do some wire splicing, but you'd have to do that with an external electric pump as well.

I believe the Aeromotive pump I used was from their SS series, but I'd have to double check.

External pump for easy access to me isn't a big plus. How often will you need access?

 

Thank you five7, definetly pointed me in the right direction.

I think ill go with the walbro and the mallory regulator, the idea of using the pump as a block off is great at least until the motor drops in. Ill just have to get my hands on an Efi pick up and wiring diagram.

Thanks again!

 

I put a 255 pump in my 84 that originally came with a carbed motor. What I would do is buy a sender for a later year like I did, an 88 to be exact, one that came with an in-tank pump. Then installed my pump onto it. Fromthere I used a painless fuel pump harness to wire it up since I didn't have any factory pump wiring. Little more than a year now with no issues. I love how quiet it is.

I did try and run a Holley Black and a Holley blue pump, external to the tank. Burned both out and basically wasted $300.00 on them once i included shipping. Get an in tank pump, saves you a bunch in the long run, and it's much, much quieter.

 

Hey ozz thanks for the reply,

Do you have a part number for the painless kit u used? I think i would rather use that instead of splicing everything.

 

I"m heading to work in about 5 minutes but I'll look it up when I get home tonight and post it for you. The only issue that I had to figure out for myself, was which fuse port to use in the fuse box to get "hot with key on" and then I had to purchase extra wire to run the entire length of the car from engine to pump since the kit comes up about 4ft short.

 

Alright thanks ozz i appreciate the help, by the way which fuse did u end up using?

 

Here is a link to the kit I used. Both Summit and Jegs have them, just search the part number.

Painless Weatherproof Fuel Pump Relay Kit

As for the fuse, I have a couple unused spots in my fuse box, I just used a multimeter and tested them with the key on (Ignition on, car not started), for power. You'll have two main power lines. One from the battery and a second one that you'll run to the fuse spot in your fuse block. This second one is the line I ran to the main power line to energize the relay. The instructions are pretty good in the kit so you shouldn't have any issues.