98 5.7 vortec efi conversion to a carb
 

i have a 98 vortec efi and i want to put it in my other 86 chevy truck. has anybody have any experience with converting a 98 vortec efi to a carb. need help.

Re: 98 5.7 vortec efi conversion to a carb
 

No, i don't have any actual experience, but the subject intrigues me; You can take a decent car in fairly good shape and make it simpler and thus easier, cheaper and more efficient to maintain fix. This, in turn, makes the car very economical over the long haul.

My main concerns are:

1) What to do with the in-tank pump; This is one of my main reasons for switching back to carbs because i think diagnosing this and, if necessary, having to change the pump would be a major pain in the rump. Can we leave the tank in the pump and just not use it? Would this be a constriction in the line?

2) What are you going to use in place of the in-tank pump? Most of these vortec v-8's don't have the hole drilled for the mechanical fuel pump pushrod. Some of these blocks do, but if they do then will the cam have the lobe to drive the pushrod? If we are going to continue to use the in-tank pump then to me this defeats the whole purpose of switch back to carbs---might as well continue using efi.

3) a simple electric pump located outside the tank. i would recommend carter.

Re: 98 5.7 vortec efi conversion to a carb
 

It is a drop in....you will need a vortec intake manifold and regular hei ignition;you can use your 86 ignition if you put the later drive gear on for the roller cam.
AC Delco makes a nice inline electric pump....6472657....

Your 86 should not have an in tank pump as it is a carb truck

Re: 98 5.7 vortec efi conversion to a carb
 

yea but its easier to convert a 98 efi to a carb than wiring all those wires and computers and you have to wire up. And in a 86 chevy i dont think we have a pump inside the tank. im puting the 98 chevy motor in my 86 chevy truck

Re: 98 5.7 vortec efi conversion to a carb
 

Whoops, i didn't catch that. In that case my main concern is what to use as a fuel pump. i would like to stay mechanical, but i don't know if using a rotary vane type driven by a belt is practical in this application.

Now, there is a special jig to drill a hole for the fuel pump pushrod, but it's pretty expensive and then we would have to figure out if the cam actually has a lobe to drive it. A decent machine shop may be able to drill the hole for you.

Re: 98 5.7 vortec efi conversion to a carb
 

I put a 1990 tbi motor in my 86, I had to file the center 4 holes in my aluminum intake as the 4 center intake bolt holes on the 1990 motor go straight down where the 86 bolt holes are on an angle. The 1990 block is does not have a hole for the fuel pump so I hooked up an inline Holley fuel pump made for carbs(3-7psi). Bolted on my carb and it ran great, I used the 86 wiring and distruibuter.

I think what you are looking to do would be very possible
Posted via Mobile Device