'83 C10 TBI swap
 

So I have a "90 Suburban that I am using for a donor. I mean complete, drove it home. Has 158,000 miles.

I am in the process of switching everything , and I mean everything, from the front seats forward. The '83 is just about ready to receive its new(er) parts, In getting it ready I had wondered about the fuel system, been searching and seen several say 5/16 is used for return line on TBI, the '83 has 1/4 return. The Suburban is 5/16 return.

Haven't decided if I am going with '87 sending units and pumps or frame mounted pump.

So my question is, will the 1/4 return work with the TBI?

I pretty sure I will just change it out and do it the way the 'Burb is, but kinda wanted to ask and just post something about the project.

Re: '83 C10 TBI swap
 

Do it correctly. 1/4” to 5/16” tubing doesn’t sound like much, but 1/4” is actually 36% smaller - pretty significant to lose over 1/3 of your flow capacity.

Re: '83 C10 TBI swap
 

2nd what he said...

This is kind of an example. I have a supercharger add on kit (pro charger) on a 350mag marine engine. It is a merc multi port FI engine. As the boost rises there is more fuel needed to stay at the optimum mixture...to compensate for the higher demand of fuel needed procharger uses a boost reference regulator that restricts the RETURN side of the pump. This increases the spray when the injector fires, (cars typically increase pulse time to accomplish more fuel demand)

I told you all of that to say, the restriction may bump up your pressure and cause a rich condition that would be hard to diagnose

Re: '83 C10 TBI swap
 

ok, I will change it to 5/16.

Thanks for the replies.

Re: '83 C10 TBI swap
 

If you can afford them and find them, switch over all the fuel components to the TBI setup. Purchase the baffled tanks, the sending units, and the switching valve for a 1987 r/v truck. These should all bolt right up to your 1983, and will be completely correct for your TBI system. Do a little research into the fuel pump. The stock TBI pump was barely adequate, and most folks install an upgraded pump instead.

These TBI side-saddle tanks and senders have been in short supply over the last year. Some key manufacturers have stopped making them, and the demand has gone through the roof because all the LS-swap guys are wanting these components as well. I think they're increasing in supply again, but I can't guarantee you'll find everything you need.