Hey everybody..... Few questions. First, how do i know if my car is TPI or TBI, im assuming TBI because i have a carb. errr i should start with my basic info, its a 86 305 carb iroc, my engine will be dieing soon, well hopefully, and i have that crappy LG4 engine in there with the stock 180 horses or 160, whichever it was. I want to put a 350 in there and it was recommended that i get TPI swap. What do i have to do exactly for this, and with my CC carb, will i have to/be able to keep the 4 bbl quad-jet on the engine, i know that my father is against taking the computer out, but would that be neccessary or recommended? Also, i have a standard 5 speed manual tranny, would i have to change the clutch, flywheel and pressure plate so that it doesn't get demolished with a 350 in there? Im sure you guys know exactly what to do, you guys never fail me! I really appreciate you guys helping me out!

 

TPI is an induction system.
You cannot have both TPI and carburetor....
it's either or.

If you already have a CC carb, then it would be far easier to just swap on a non CC carb, intake, and distributor for the 350.
It's much simpler and makes more power for far less money.

 

A ton of stuff, staring with an entirely different wiring harness, computer, a bunch of sensors and modules and an electric fuel pump in the tank (or mounted under the car).


The TPI replaces the carb with a fuel injection set up.
Hmmm GM wouldn't put that trans with the 305 TPI's, so I doubt it would hold up to a 350.

 

so what would be a rough estimate of what the total cost for the tpi swap would be? Is it worth swapping? Im still confused about the TBI, is tbi involving anything carbed?

 

TBI is basically a carb, but the internals are different, instead of using a fuel bowl and float and needle valve, it uses injectors (2 usually) that are plumbed into the bottom plate of the "carb" body.
At first glance the early TBI setups looked very much like a carb.

I wouldn't even hazard a guess on the cost of a TPI swap, it depends on if you want all new parts or used. You can find "complete" TPI setups on E bay for $300-$500, some will have the harness and ECM, others won't, somw will come with all the sensors that fit on the TPI manifold, etc, and others won't.

One thing you will have to do that will be a oain, is replace all of your rubber fuel lines with fuel line suitable for feul injection. Stock carb or TBI fuel lines are low pressure (20 psi tops maybe) amd TPI uses higher pressure lines (TPI runs 43 psi from the factory)

Doing a swap like that can be very time consuming and frustrating, not to mention exensive.