TBI 350 to Carb?

[1980]

Hey Guys,
I ran across a 350tbi engine for cheap on craigs list.
I haven't seen it yet as its 200 miles away. He says its in an 85 burb, 120,000 miles, runs great. I'm looking for a replacement for my 80 k20 or my 79 k1500.
Is a conversion to a carb easy, I really want a simple bolt in, so how difficult would this be? Did they even make a 350tbi in 85?
Thanks

 

[K5_Fla]

don't think TBI started until 87..... I could be wrong. Anyway...my truck has a newer TBI motor that was converted to carb.... runs perfect. All you need is a good fuel regulator....depending on what type of pump you have.

 

[4xcrazy]

TBI in '87, unless he converted his '85 over at some point. It'll work, replace the intake manifold with yours, you will have to drill out (wallow out) the 4 center intake mounting bolt holes, the TBI ones are a straight down setup. other than that, you'll have center bolt valve covers, which in my opinion are much better than the old oes, they don't tend to leak as much

fuel pressure regulator?? he's not going TO TBI, taking a TBI motor and putting a carb on it. use the same setup you currently have, just swap out the manifold.

another thing, i would ask for a picture of the casting numbers on the back drivers bell housing area to verify that it is in fact a 350. 305's look the same..

 

[tRustyK5]

I think the regulator comment was meant for a TBI truck getting a carb, but retaining the original in tank electric fuel pump. You'd need to dial down the pressure to the carb to the 5-7 psi range.

Rene

 

[Bowtie85]

I swapped a 90 350 into the blazer. I bought a pro products intake that had the holes already reamed and little adapters for the center intake bolts.

 

[dave w]

The mechanical fuel pump from the 1980 motor will more than likely not bolt to the TBI engine block. The factory changed the one piece rear main seal block casting; some / most one piece rear main seal TBI blocks do not have the fuel pump push rod hole drilled out.

dave w

 

[4xcrazy]

My '89 still had all the holes in it and mounting for the mechanical fuel pump. now the cam on the other hand may be an issue, might not have the lobe to push the fuel pump pushrod...

 

[Bowtie85]

my 90 has the plate/and was drilled for the rod, and the cam has the fuel pump lobe on it.

i have seen some blocks that just have the casting provision but not plate or drilled holes, have also seen a couple that have the push rod holes half drilled. when we pulled my vortec 350 apart, the cam did not have the lobe for the fuel pump either i believe as well.

 

[dave w]

The mechanical fuel pump from the 1980 motor will more than likely not bolt to the TBI engine block. The factory changed the one piece rear main seal block casting; some / most one piece rear main seal TBI blocks do not have the fuel pump push rod hole drilled out.

dave w

Update with pictures.

dave w