305 4bbl To 350 TBI? Whats Parts Are Needed?

[dream on mcss]

Ok, i know this has probably been discussed a million times, and i did try to search for it and couldnt find exactly what im looking for. Me and my friend are putting a mid 90s 350 tbi out of a full size conversion van in the place of the weak 86 smogged up 305 4bbl. I have a few questions as to what parts we need and was hoping that you guys could give me some good answers.

Question 1: This engine has provisions for a mechanical fuel pump. Can you run a mechanical fuel pump on a TBI engine or do we need an electric fuel pump and a block off plate?

Question 2: If an electric pump is needed, will we need a gas tank from a fuel injected 4.3L v6 monte carlo/gn or can we just run an inline pump and keep the stock tank?

Question 3: If we run an electric inline pump, that means we need a return line and a regulator, correct?

If theres anything im missing, will someone please chime in? We really want to do this swap right so please help .

 

[darbysan]

I'll try and give you some of the answers. You will need and electric pump, 14 PSI. Mechanical pump cannot provide that much pressure. You can install in line, or in the tank. In the tank provides cooling for the pump, and is quieter, but inline will work OK. I would change the rubber hoses from regular Fuel Hose to FI hose. You will also need an inline filter. I used Fram G3870- it has 3/8 barb fitting on both ends. I would also use FI hose clamps- you can buy them on Ebay in batches of 10.

I do not know if a separate regulator is needed or not, assuming you have the correct TBI pump. Others need to chime in here. On my TPI setup, I used the 5/16" Vent line for the return line ( swapped at the tank- the vent line at the tank has a restriction in it). I used Fuel Hose for the tank vent line to the Charcoal Canister. Some Monte's had a fuel return line ( 1/4"- I think). I have heard others use this for the return with no issues.

A baffled tank will only be needed if you install the pump in the tank, and you can even get by without it as long as you keep the tank 1/4 full. New tanks can be purchased from Rock Auto, and new Fuel Senders are available here for $125:
http://www.tanks-to-pans.com/site/823208/product/FG156A

I'm assuming the new engine has all the front accessories ( serpentine?). If so, the water pump is a reverse flow from a stock 305 pump, The mechanical fan also is a reverse flow fan. Don't mix and match these.

 

[dream on mcss]

I'll try and give you some of the answers. You will need and electric pump, 14 PSI. Mechanical pump cannot provide that much pressure. You can install in line, or in the tank. In the tank provides cooling for the pump, and is quieter, but inline will work OK. I would change the rubber hoses from regular Fuel Hose to FI hose. You will also need an inline filter. I used Fram G3870- it has 3/8 barb fitting on both ends. I would also use FI hose clamps- you can buy them on Ebay in batches of 10.

I do not know if a separate regulator is needed or not, assuming you have the correct TBI pump. Others need to chime in here. On my TPI setup, I used the 5/16" Vent line for the return line ( swapped at the tank- the vent line at the tank has a restriction in it). I used Fuel Hose for the tank vent line to the Charcoal Canister. Some Monte's had a fuel return line ( 1/4"- I think). I have heard others use this for the return with no issues.

A baffled tank will only be needed if you install the pump in the tank, and you can even get by without it as long as you keep the tank 1/4 full. New tanks can be purchased from Rock Auto, and new Fuel Senders are available here for $125:
http://www.tanks-to-pans.com/site/823208/product/FG156A

I'm assuming the new engine has all the front accessories ( serpentine?). If so, the water pump is a reverse flow from a stock 305 pump, The mechanical fan also is a reverse flow fan. Don't mix and match these.

Thanks darbysan! So to clarify:

We will need a block off plate, an inline fuel pump, and we wont have to use a monte/gn tank? We'll also need a regulator and a return line too? If anyone has any pics of their setup it would be great ...

 

[darbysan]

Thanks darbysan! So to clarify:

We will need a block off plate, an inline fuel pump, and we wont have to use a monte/gn tank? We'll also need a regulator and a return line too? If anyone has any pics of their setup it would be great ...

As I stated, I really don't know about the regulator or the return line. I don't know if the TBI has a built in regulator or not. Need someone with TBI experience to answer up!

Looked it up on Google. The TBI unit has a built in regulator. You will need a return line.

http://members.shaw.ca/betterthanyoutoo ... pr/fpr.htm

 

[othtim]

The TBI throttle body has a built-in regulator, but its worthless. Just spend the money and get a decent aftermarket regulator. You can get away with the stock regulator, but only if youre looking at not improving the performance of your car at all. IE keep the HP around 200 and dont rev past 4000 rpm.

 

[othtim]

I've done the swap in an 88 truck - originally a 305 q-jet. so I'm fairly familiar with it. if you have any qs ill try and answer them.

 

[dream on mcss]

The TBI throttle body has a built-in regulator, but its worthless. Just spend the money and get a decent aftermarket regulator. You can get away with the stock regulator, but only if youre looking at not improving the performance of your car at all. IE keep the HP around 200 and dont rev past 4000 rpm.

I know its been awhile but I did some research yesterday and found that the stock regulator can be tuned. Those guys on thirdgen sure know there sh*t! Basically what this means is that an aftermarket regulator is the same as the stock one, the only difference is that the aftermarket regulator has a screw. The stock regulator has one, your just have to take apart the TBI unit to tune it. Read up on this sh*t:

http://www.thirdgen.org/tbi-afpr

Also, I came up with a diagram for the fuel system, and I wanted to know if thats how we would need to run it. If its not right, someone please change the diagram to the right setup.

 

[Dave V]

i have done this setup twice in my 83 and 84 el camino and i am running a gm in tank setup we welded a return line int the tank. also im running the stock gm regualtor and a jet chip in my computer and i can rev all the way to 5500 rpm.

 

[dream on mcss]

i have done this setup twice in my 83 and 84 el camino and i am running a gm in tank setup we welded a return line int the tank. also im running the stock gm regualtor and a jet chip in my computer and i can rev all the way to 5500 rpm.

So do u know if the setup in the diagram for the fuel lines will work?

 

[Dave V]

it may thats not how i run mine and im running the stock type silverado fuel line setup as i pulled it from the donor truck. my fuel filter is on the frame rail between the door and front wheel and my pump is in the tank.