TBI or Carb..

[shaun89]

Well in the next few weeks i am swaping motors. right now my 305 is tbi set up, the motor im getting is a crate motor outta an 85pick up w/ 30.000 on it, it has a high rise manifold and holly carb. So far my search for the 350 tbi stuff leads me to spending almost the same amount that im getting the engine for. What will be the downfall if i just keep the 350 carbed and thrown into my truck with a 700r and 208, my trucks an 87 too.. any computer stuff w/ the tranny at all? So.. Pro's and Cons to both would be helpful.

 

[Russell]

Converting to 350 TBI isn't that expensive I wouldn't think...

I managed mine for under 50 bucks. Just got a 350 prom from the wrecking yard (the guy behind the counter just kinda raised his eyebrow and said I could take the chip for free), a set of 350 injectors (not the whole pod, just the little injectors, again, a raised eyebrow, and go ahead and take em)

Paid for the knock sensor and EST module, and a big cap EST HEI from one of 81+ trucks so I wouldn't need to worry about possible cam gear differences between the 73 Nova engine, and 89 dizzy, plus it eliminates the messy looking remote coil.

 

[shaun89]

hmm yeah i've called a few big junkyards in the area, only 1 had it and wanted 150 for all that.... any other thoughts? will the carb die on me when climbing steep hills?

 

[350k5]

hmm yeah i've called a few big junkyards in the area, only 1 had it and wanted 150 for all that.... any other thoughts? will the carb die on me when climbing steep hills?

Yea, that is a big downside to carbed trucks, when climbing a steep hill you can loose fuel and it will die on you. And while on a steep hill is not when you want that to happen. TBI would be cool but I'll still stick with my carb for now just because of simplicity - no computer controls or wiring.

 

[chevyin]

hmm yeah i've called a few big junkyards in the area, only 1 had it and wanted 150 for all that.... any other thoughts? will the carb die on me when climbing steep hills?

Yea steep hill = probs. with the carb

 

[Russell]

TBI is a pretty simple setup

Only thing you gotta be careful with is not to run too much cam. The engine is run off a set of tables that depict a stock engine. If you build it up, and want good performance from your truck, get someone to do a chip for it based off of some datalogging you do for them. Even one chip based off a good hour or two's drive (a good programmer will give you a driving plan, so you can be sure to get all the data points you need) will make a phenominal difference on getting your engine running better.

Basically, just go to a junkyard, and pull one peice at a time, most of the time I find they'll give you small stuff like that for free.

 

[shaun89]

alright, i know what the injectors are.. the computer chip is.. and all that, but what the heck is a knock sensor? what does it look like.. wheres it located on my 305? i think ill have to poke around some of those junk yards and see.. they might not know what they have. thanks guys

 

[stockk5]

anyone else?

 

[mtrdrms]

I have recently put a new block in my 87 and it was a nightmare. As stated above it is recommended that very little engine mods be done to the motor if you are using TBI. I had some mild upgrades (cam, compression, Holley TBI.) and had to get a custom burned chip and it still does not run right. If I could do it all over again I would definatly go carb or just leave my motor completely stock. The TBI 350 is an excellent set up and is reliable and makes good power but just leave it alone.

On the other hand if you are going to go for a carb setup, you will need to ditch the electric pump and go manual as well as plugging all the sensor holes in the block and getting the carb, manifold etc. Also forget about passing emissions again.

 

[dyeager535]

Knock sensor: Passenger side, just forward of the starter, approximately on the same plane on the block as starter.

Round, one wire connector.

 

[theperfectgarage]

Once you get over the fear of wires and a few sensors the tbi IS a simple setup IMO. One thing I dont like is screwing around w/ used wire harness. I recomend the ones from Howell. about 300 $ but a thing of beauty.

 

[BoDapper]

I just installed a new motor in my 87 as well, same kind of upgrade (mild cam, intake, Holley TBI) and had the same result- it ran like ****.

After chasing down the outfit that burned the prom for me I found out that they had over looked the fact that I had a Holley TBI (670). I was told that the injectors on the Holley aren't able to be controlled efficiently and that they recomended that I go back to the stock TBI. Found an outfit out of Pheonix (Carburetor Exchange) that rebuilds TBIs for $290 and ordered one up- runs great now.

Holley wouldn't take a return on the one I bought from them and told me that the injectors are set for stock 350's....put it on my brothers and it proved true, ran better than the stock TBI he had, but lost about 2 mpg.