Getting Started with my 350 swap. Help?

[RedneckNLowrider]

I am looking to put a 350 into my 1991 GMC sonoma 2wd with a 4.3 V6. The motor I have for it came out of a 1970 Chevelle and has the mechanical fuel pump, and a carb. The truck currently has the TBI throttle body and the electronic fuel pump. How do I go about getting around the fuel pumps, I guess I have to remove the in tank electronic pump. And also, what do I need to purchase for the swap other than motor mounts and headers?

[RONSTPIS10]

welcome to the site you will find alot of useful knowledge here. if you search past threads you will find info on what to do in the tank you have a couple of options.

[harleyboy]

welcome to the site and like RONSTPIS10 said read the threads and you'll get some good info. but as for the tank you can leave the old pump in there like I have and use the mechanical pump like you want.

[spacecadet]

Using the carb and stuff from your chevelle is one of the easier swaps - in my opinion.
These guys got yu going in the right direction. The only other thing I would recomend is an upgrade in membership. As a junior you can only post once a day.
Space

[Ryoung68]

You can use the in tank pump to feed the carbed engine if you want, just run the return style fuel pressure regulator to lower the PSI. Too high a fuel pressure can force the needle off the seat causing flooding. The return send the excess fuel back to the tank thru the pump to help cool during low fuel levels.

Fuel Pressure Regulator http://www.s10v8.com/store/product_info.php/products_id/49?osCsid=3899b8f63cd5ce42ee70dd230eec5527

You can also replace the intank pump with an equal length of solid or flexible hose and use the mechanical fuel pump or you can just unplug the fuel pump electical connector and just pull the fuel thru the pump (this may restrict fuel flow a bit).

Good Luck and keep us posted. :headbang:

[RedneckNLowrider]

ok, I have looked in the store on this site and found most if not all of the parts I should need for the swap. Here is the list I came up with:

S10 V8 2WD Conversion Kit Max (with ceramic coated headers)
Tranny mount (for TH350)
Fuel pressure regulator
2.8 V6 motor mounts
Temperature sensor
Dual Elecric Fan setup

That all comes to around $1100.00 when I add it up.

Does that look like the parts I should need?

I want to do this right the first time because this truck was my first truck and is my baby. Also anyone know of some one who has some of these parts used so I can save some money?

[harleyboy]

ryoung which line is the return line and the what is the other line for.

[Melonhead]

I am looking to put a 350 into my 1991 GMC sonoma 2wd with a 4.3 V6. The motor I have for it came out of a 1970 Chevelle and has the mechanical fuel pump, and a carb. The truck currently has the TBI throttle body and the electronic fuel pump. How do I go about getting around the fuel pumps, I guess I have to remove the in tank electronic pump. And also, what do I need to purchase for the swap other than motor mounts and headers?

First off, there is no NEED to use the electric fuel pump. The mechanical will suck through the pump that is in the tank. Connect the suction side of the pump to what used to be the pressure out hose to the TBI. Disconnect the relay to the fuel pump and there is no NEED for the regulator.

Fans, The twin fans are nice and fit well. There are fans you can get from the junk yard and save a bundle. The twin LT1/LS1 fans from the camaros can be trimmed to fit and wired with swithches and relays.

[RedneckNLowrider]

I think I will take the tank down and replace the pump with a piece of fuel line. I am not sure if I want to eventually go back to TBI and dont want to have to spend $70 on a fuel pump if I do that.

The bad things about this project are that I have to wait until I get off of my work schedule before I can start.... and I will probobly want to put a motor in my 92 4x4 after I am done with the 91 2wd.

[355V8S10Tahoe]

Here is an example picture of a removed fuel pump for in the tank: (it's how I did it)

[ZR1BLAZER]

Here is an example picture of a removed fuel pump for in the tank: (it's how I did it)
now thats thinking. i like the way you did that and was able to keep the sock. but you can just leave the pump in the tank. i did on my 86. once you disconnect the ecm there is no longer power to the pump. so you dont have to modify anything. and if you search the net or ebay you can find the parts cheaper.

[asfasasu3]

One thing to take note of when doing the swap is engine placement. I got ours in and everthing where I wanted it, all looked good, but could not get the mech. pump back on the motor. Ours is older, and I do have the motor set back a ways, (not that much though) but it just won't clear the frame when in position. I also have just enough room to get the distributor in or out. Just a few things to watch while doing this.

[harleyboy]

One thing to take note of when doing the swap is engine placement. I got ours in and everthing where I wanted it, all looked good, but could not get the mech. pump back on the motor. Ours is older, and I do have the motor set back a ways, (not that much though) but it just won't clear the frame when in position. I also have just enough room to get the distributor in or out. Just a few things to watch while doing this.
Thats why I went with a electric pump I tried to put one in and I would of had to take piece of the frame out dont have to tools for that so that is what my choice was.

[355V8S10Tahoe]

now thats thinking. i like the way you did that and was able to keep the sock. but you can just leave the pump in the tank. i did on my 86. once you disconnect the ecm there is no longer power to the pump. so you dont have to modify anything. and if you search the net or ebay you can find the parts cheaper.

Well thanks ZR1BLAZER, but I never liked the idea of my mechanical pump pulling fuel through the in-tank pump causing a fuel restriction... I've done three in-tank pumps this way and it's a good thing because in the S10 Tahoe tank the filter sock was damaged and had fallen off the pump, who knows what trash had already went up in the electric pump clogging it... This setup has two fuel screens, if the sock (as you call it) falls off, there is a 100 mesh screen in the wider section the sock presses onto, this helps save my fuel filter before the pump up front... A new filter sock was all I had to buy anyway... The section the 100 mesh screen is in is from a central A/C unit, it's a (cut off on one end) liquid line screen... You can't see it very well but there is a diagram of it to the right of the picture below...

[RedneckNLowrider]

Well my Fuel pump just went out on my sonoma so I have decided it is time to start the swap. I plan on starting to remove the 4.3 this sunday and clean up the engine housing. Hopefully I will be able to get it all finished within the month.

I have heard somewhere that I can get a low profile distributor for the 350 to allow better fitment with the firewall. Anyone know where I can get one of them, all I have now is the one that came with the motor and it is about 4-5 inches tall.

[racer1182]

an hei will fit but you can also look into an msd or something small like the old style points distributor and convert it over to electronics instead of points. are you goin carbed on this or fuel injected?


Greg

[RedneckNLowrider]

im going with carburated, I dont want to deal with the fuel injection right now. I got the motor pulled between sunday and this evening. Going to clean up the engine housing this week and pull what wires I can out of the compartment to get it cleaned up. Does anyone know an easy way to tell what wires I can pull and which I should leave.

[harleyboy]

all the wires on the computer will come out and the wires by the brake booster are the ones you keep I'll take a pic of mine unless some one else can tell you the colors cant remember off hand.

[HardinValleyMagic]

355, is that a piece of copper tubing and a reducer soldiered on the end? Will the gas not have any effects on the coppper if so?
Cool idea. Who ever did mine took the pump off and just left a screen on a stright pipe. So I found out the hard way that 1/4 tank=EMPTY. LOL!

[RedneckNLowrider]

So far I have removed the engine, AC condenser and components, blower motor, cruise control paraphanalia, and all of the front fenders/rad support. Now I am trying to wire wheel the frame and paint it along with the entire engine housing that I can easily get to.

My only problem is the dang wires. I have been thinking about what I want to do and what would be easiest and have realized that I am not an electrical person by any means. I want to keep the factory gauges so I know I need to find the sensor plugs and retain them. Do i have to keep the computer and assiciated wires for any reason?

Does anyone know where I can find electrical schematics for the required connections for the swap?

[HardinValleyMagic]

Here you go. http://www.autozone.com/az/cds/en_us/0900823d/80/12/41/a3/0900823d801241a3/repairInfoPages.htm Should have diadrams for you.

[RedneckNLowrider]

Im still working on the wireing, but I have thought of something else that I have a question about. The 350 motor is about the same length from the flywheel to the front of the water pump as the stock 4.3 was. Will I have enough room with the standard water pump to put an electric fan in front of the readiator. I am using the stock radiator for now, and would like to know if I have to buy a differnt water pump to run in my truck? If I do have to buy a water pump, then I would have to change all the other accesories on the motor to fit the pulleys. What have yall done for this or will the stock one on the 350 work.

Also I currently do not have an alternator or power steering pump on the 350 and need to get one. Will any of the stock accesories such as the alternator and power steering pump work on the 350?

One more thing. I plan on removing my A/C and want to do away with the big box that had the condenser in it. Can I find a similar truck without AC and use the blower box from that?

Thank you,

p.s. how do you post pictured in posts?