Fuel question's

[Mcsjr454]

Howdy all, I am redoing my 2nd 79 K5 Blazer, but this time as a rolling restomod, instead of a ground up custom. My final plans are for a daily driven 5.3, 4l60E, np241. 3.42:1 Gearing, on 31.10.50's. The fuel tank and lines need replacing as the ones in it now are rusted and leaking. So I figured since I will need the 87 model tank and sending unit I might as well replace those now, as I will need them later. The problem I have is, I have never ran an electric fuel pump to a carbed engine. (350 cid, stock, 170 hp, AC, PS) So with the knowledge of using a 1987 K5 Blazer tank and sending unit, what Regulator would I need to keep things working happy together? Would I run a bypass, or let the pump dead head? and would I keep the charcoal canister functioning or disconnect it? Any help would be appreciated, and constructive criticism is greatly appreciated.


My previous custom mentioned started as a daily driver along the same route, but quickly snowballed out of control after a few parts selections gone awry. When you start planning a project, don't set your mind on specific parts. Instead look at what is available, and what is being done. Often you'll find something better than you plans, that also has more potential.

 

[79rustyk10]

I was planning on doing something similar. I would use a bypass regulator to keep the pump from overheating and dying prematurely.

A TBI pump would work well for the time being, and I think theres higher pressure options for when you do the 5.3 swap.

When I swapped 1988 TBI 350 into my 79, I axed the charcoal canister.

 

[wazzabie]

If you are going to buy new lines get stainless from Inline Tube. They are rally nice and not to costly. You could run fuel line all the way back but I like the piece of mind knowing the lines are solid. Also it is much easier to but them prebent then to try and bend them yourself. just my 2 cents after having tried this.

 

[Mcsjr454]

Update: I decided to go with a 1987 Blazer 30 gallon tank, with factory 87 in-tank pump. The factory pump peaks at 20psi on a deadhead load and 15.5 continuous bypass, but is a return style pump, so a bypass regulator is required. I found this one (JEGS Performance Products 15909 - JEGS Billet 2-Port Adjustable Fuel Pressure Regulators) that is working very well on my factory Q-jet. As for fuel line, I considered running stainless hardline, but opted to go to a flexible fuel hose as I am intent on changing the setup over the next few months to a 5.3, which would require new fuel line again, so here is what I used (JEGS Performance Products 15992). It's black, it's simple, and it's temporary. Be sure to use a good high quality barbed fitting. I have not installed the fuel pump block off plate, opting instead to leave the factory fuel pump in place, as again, things are temporary in the gathering of parts stage.

The 1987 tank bolted directly in using the 79 fuel straps, fuel level wiring had a different plug but was easily fixed, the charcoal canister line fit perfect, as well as the filler line. I ran new rubber line forward, as well as the return line from the aforementioned regulator. Wiring for the electric pump was straight forward, I purchased a generic relay kit from autozone, and wired the switch side to a hot when keyed fuse.

Things of note, cranking time to start, after sitting for a few days, has reduced significantly, no more waiting for the fuel bowl to refill. Use shrink tubing on wiring connections, and use candle wax on hose end barbs, it makes things go together easier and stops the rubber from bonding to the metal. GM weather pack connectors, make future maintenance easier, and they can be purchased cheaply.

All-in-all, even if you are not going to a fuel injected setup, I would consider this swap for anyone in need of tank replacement. It took me 6 hours, (and I work very slow) from dropping the tank to turning the key for the first start.

Next up is the brake system.

 

[sweetk30]

watch the fuel hose stuff. if not efi pressure rater it will go bad fast. guy on othersite almost lost his car the other day from cheeping out and running all rubber NON efi pressure rated hose. lucky it blew out on cold start up and not hot or it would have burnt up the car.

and go find or get a electric fuel pump for a 96-97 only c or k truck with 305 or 350 vortec it will swap right in place of the tbi pump now and get you the 60+ psi required for the later model vortec 4.8-5.3-6.0 motor needs.

search the engine swap section here for ls swap builds. and we even had a member here get his truck used for r&d testing at doug thorley headers if i recall to make the proto type set of 4wd and ls engine headers since the swap is so popular now.

if you dont want headers or dont have the cash few option out there.

click the 2wd build link in my signiture and read up on the mods i did for my ls 5.3 swap in a 2wd that will also work for 4wd swap. lots of pics but have to be a paid member to see mine as hosted here.

any more info / help just ask .

 

[Mcsjr454]

watch the fuel hose stuff. if not efi pressure rater it will go bad fast. guy on othersite almost lost his car the other day from cheeping out and running all rubber NON efi pressure rated hose. lucky it blew out on cold start up and not hot or it would have burnt up the car.

and go find or get a electric fuel pump for a 96-97 only c or k truck with 305 or 350 vortec it will swap right in place of the tbi pump now and get you the 60+ psi required for the later model vortec 4.8-5.3-6.0 motor needs.

search the engine swap section here for ls swap builds. and we even had a member here get his truck used for r&d testing at doug thorley headers if i recall to make the proto type set of 4wd and ls engine headers since the swap is so popular now.

if you dont want headers or dont have the cash few option out there.

click the 2wd build link in my signiture and read up on the mods i did for my ls 5.3 swap in a 2wd that will also work for 4wd swap. lots of pics but have to be a paid member to see mine as hosted here.

any more info / help just ask .

Yeah, the line I used is rubber, but has a burst rating of 50 psi, i'm well within maxing at only 20 psi. Thanks for the info on the 96-97 pump, I didn't know they would interchange.

 

[sweetk30]

if you ever go efi then you will need new rubber line as efi is 60+ psi average.

 

[Mkuhn138]

Use a return style regulator. I just converted from TBI to carb and ended up running AN hose and fitting where I had to change thisngs around- you just need a few metric inverted flare to AN adapters. The summit branded AN hose and fittings are very reasonable and work just fine.

Edit - didn't see that you were already done.