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What is involved with carb swapping a tbi 2.5?

2068 Views 39 Replies 8 Participants Last post by  tmbrake84
I have a 1987 2.5 s10 5 speed and have had an extremely difficult time with my computer and getting everything running with the computer so I was wondering what all it would take to just carb swap the 2.5 tbi?
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Not to dig up an old thread... BUT...
GM made 5 intake manifolds over the years for these POSs. There was never a carb version intake for an 89 Duke. IIRC, the last carb was on an 83 Jeep or Citation. Everything newer was TBI. Jeep used the Duke for 3 years from 81 to 83. The intake was totally different for later years. Spelled - it won't work.
I have a custom made intake with a Holley 2 barrel base that was fabricated for this conversion. I'll try and post pix soon.
The easiest way to go "carb" is to use a Chevy 250 six cylinder one barrel and fab a simple adapter.
You'll have to figure out a throttle linkage - particularly if your rig has a 700 R4 in it. The TV cable is critical for the transmission.
A pre 1984 distributor is required also. They are on line rebuilt. HEI with the big cap. One wire and you're done
DO NOT and I repeat DO NOT hack any wiring off. You can simp ly tie wrap all of the wires and move then under the HVAC in the engine bay. You are probably not a member of the ABU (hopefully) - Amalgamated Butchers Union
I have used a "T" fitting to bypass the high pressure from the TBI fuel pump. This will be more than adequate for a carb without having to change stuff. You simply add the "T" to the pressure side and rout it to the return. The "T" leg goes to the carb.
If you PM me, I can add detail.
There are a feww threads here that have done this conversion successfully.

I've done a few conversions on S10s that worked very well...
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1983 Jeep Iron Duke. Has the Chevy Small block bell hosing bolt pattern - RARE!!
Bell housing has the Ford transmission bolt pattern.
1987 Ford Turbo T Bird 5 speed Borg Warner T5

Heavily modified -
High compression Chevy small block pistons
500 lift 96* HUGE cam
Big block Chevy roller rockers
Ported head with large intake exhaust valves from an Olds 350
Chevy 327 small journal I beam rods
Aluminum timing gear set
Balanced rotating assembly
Lightened flywheel
Offehauser 4 barrel intake
Holley 390 CFM 4 barrel Carb
HEI distributor with advance curve modified
Stock exhaust manifold opened to 2.5"
Heavy duty 10" clutch assembly

Once installed and run in, I'll dyno it to see what kind of power it makes...

So, can you carb an Iron Duke?
The answer is yes - sort of.
As I previously posted... they make intakes for the early Dukes, but later editions require some skill and imagination.
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