TBI compatibility

[hi pinion]

Ok, so lets say i found a tbi complete from an 89 blazer, but its a 305. And the truck i am wanting to put it on has a 350. Is the system worth buying if i can get it cheap? What mods are necessary to make it work for the 350? And is it worth it , or not?

 

[hi pinion]

Oh yeah the one im wanting to put it on is a 85 CCC truck ,,and i might be able to get the tbi stuff (complete) for around 100.00

 

[Russell]

All you'd need would be a new knock sensor, ESC module (not mandatory) 350 injectors, and a 350 prom. The rest of the sensors are the same, as is all the wiring.

To change to a 350 prom, just find a TBI 350 ECM, pull the chip out of it, and put it into your current ECM, or just buy the full ECM, and keep your old one as a spare (the chips are very easy to change, just make sure that you do not give the ECM a static shock, ground yourself to it prior to touching anything).

Injectors are easy to change out as well. Just pull the whole injector pod off (gotta undo the fuel lines, and the adaptors into the pod to get it off) and put the new one on. The connectors are the same.

Knock sensor takes a few seconds to remove with an impact gun and the ESC module takes a few seconds. ESC really isn't nessessary, the only difference between a 4.3, 5.0, and 5.7 module is in when and how much it retards the timing when pinging is detected with the knock sensor. Unless something is wrong the engine, it shouldn't be pinging with the factory timing curve, so it really shouldn't make much difference.

 

[hi pinion]

so should i buy it? would it be worth it for 100? How much money is left changing all that over?

 

[Russell]

I converted my 305 setup to a 350 setup for 20 bucks from the local wrecking yard.

100 is not a bad deal for a totally complete TBI setup at all Definitely pay more on ebay! Just make sure it comes with absolutely everything though -- Pull it yourself if you can. Cut wires are a pain in the butt, and if you are missing little things, that $100 TBI setup could become more like 3 - 400 real quick! (sensors are not cheap if you get them new)

 

[Thunder]

Besides the stuff already said you will also need an in tank or in line fuel pump for TBI. In tank pump is the best. Will also have to plumb a return line back to the tank. Best bet is to get the whole gas tank and lines off the Donor truck

Make sure you get the TBI distributor off the TBI engine. TBI wont work with older HEI ignition.
The TBI manifold wont bolt up to older heads without doing some drilling and grinding on the center bolts to get the angle right. You can get an adapter to bolt TBI to your Qjet manifold. but may have some issues getting the EGR set up right.
Not sure if the cam in a CCC carbed engine will work with TBI.

If you live in a SMOG law state might you want to see if the swap is legal.

IMO its worth doing the swap but it will cost you time and money to do it right.

 

[dyeager535]

I absolutely concur with the fuel line stuff. Get the entire setup out of the donor if it's the same vehicle (k5-k5 for instance) and bolt it up.

Trying to adapt the fuel line fittings, bend new lines, etc., is a complete PITA, and adds cost and complexity.

 

[Russell]

Besides the stuff already said you will also need an in tank or in line fuel pump for TBI. In tank pump is the best. Will also have to plumb a return line back to the tank. Best bet is to get the whole gas tank and lines off the Donor truck

Make sure you get the TBI distributor off the TBI engine. TBI wont work with older HEI ignition.
The TBI manifold wont bolt up to older heads without doing some drilling and grinding on the center bolts to get the angle right. You can get an adapter to bolt TBI to your Qjet manifold. but may have some issues getting the EGR set up right.
Not sure if the cam in a CCC carbed engine will work with TBI.

If you live in a SMOG law state might you want to see if the swap is legal.

IMO its worth doing the swap but it will cost you time and money to do it right.

Oh, thanks for reminding me!

On the distributer note, make sure that you change the ring gear out for an old style HEI ring gear! The newer ring gear will chew up the old cam. Its easy to do, just knock out the roll pin, and swap the ring gear from your old dizzy on.