Here's a comparison of changing to carb vs. changing to an aftermarket TBI (The Holley 670 unit) ONLY because they're the closest in price. However they're NO WHERE NEAR the same flow. I changed the flow rates to better match each other, because when comparing $$$ we have to keep that in mind.

It costs more $$$ to change a TBI car to Carb than it does to buy the Holley 670 unit.

The Holley 670cfm (475 @1.5"/Hg) unit costs ~$320
The software and hardware combined to burn chips costs about $140 (based on information JPrevost has said).
Total cost $460

To change to a carb REQUIRES more changes.
A 4V carb as small as 600cfm @1.5"/Hg w/elec. choke costs ~$260
A new manifold can be had for ~$100
A Mallory 3 port regulator (or equivalent) ~$70
A new vacuum/mech advance dissy ~$150
Total cost $580

There you can see as far as up front costs, the TBI wins by $120.

However, if you change to a higher flowing TBI intake, you're talking another ~$210. Now the carb is cheaper by ~$90. It's not a requirement though, so keep that in mind. The comparison above is comparing only the requirements.

However, you have to keep in mind that the carb is going to flow more, and the TBI is going to be more "driver friendly". They each have their perks. You can't say one is better than the other, because they are BOTH better than the other when talking about different characteristics.

An advantage of carb is they flow more for less money. A 750@1.5"/Hg carb can be bought for ~$250. An equivalent TBI requires a new ECM, etc. which costs more in the end. This is not to say there aren't good aftermarket TBI systems out there. Some flow as much as 900cfm @1.5"/Hg, but cost $1400.

A HUGE advantage TBI has is it's required by law to keep it. If emissions tests are not required in your area, then you may get by fine. Just keep in mind that even if you don't have emissions testing in your area, any police officer can do a visual inspection of your car, and if all the factory emission equipment is not there, you can be charged UP TO $25,000 by the Federal Government. That's a very expensive carb!!!!!!!

It all comes down to what kind of HP you want and what your intentions are for the car. It's like anything else when modifying a car. Pick your goal and stick to it.

I hope this helps clear up some decision for people. Heck...... I'm still not sure what I want to do with mine. There are advantages to both, but I have yet to decide which advantages I would enjoy more.

 

To those considering a carb...
if your not upgrading to a hot 350 or somehting like that, id stay witht he stock tbi. As long as your not spinning past 5000 itll adiquatly meet your engines air requirements. A 670 tbi or a good carb will be more then you really need. The big restraint is the timing and fuel tables in the ecm. Id say just go get the prom burning equipment and dial it in that way. I suspect youd see great imporvements. To give a good example of how bad the timing tables are, jsut to get my engine to run acceptibly with the stock chip, i have to run well over 20 degrees of base time as opposed to the stock 6 degrees taht is called for. Even with my 350 and mild cam, the tbi doesnt have a noticable pressure drop untill after 5k and my power dumps off after 4.5 k so that has yet to be a restriction.

 

If your mechanically inclined, as am i. It certainly is far more cost effective for the carb.... observe.

Carb... 600-750 vac sec, picked up at yard sale, or swap meet. 30-50 bucks Tops.
Rebuild kit 25 bucks.

Intake manifold 40-100 bucks. depending on the type and where you get it from.

dropping the tank, getting rid of the electric pump, making a pickup, and bending some lines in the tunnel to a manual pump, and a 6psi 120gph. 10 bucks for 3/8 line, and 57 for a pump.

10 bucks for a core distributor from a bone yard, or joe schmoe doesn't matter.. a new pickup coil, and a pertronix makeover kit, 125, so 135 total. for a distributor you know has all new parts and is built right.

highball total ..... 377 dollars.

That's still enough left over to buy a holley jet kit, @ $36, a quickchange cover, 7 bucks, a whole pump cam assortment @25 a whole spring assortment at 10, which should cover every incarnation you'll ever come up with on the car, still leaveing enough left over for intake gaskets and a 12 pack.

and that's with the high range of prices, get lucky here and there, and you've got enough for a new cam

just a matter of looking for things in the right places

to add to that. you get to pull the computer out, pull the harness through the right fender, disconnect everything, set it aside, and sell it to someont looking for one, and make a profit off that. and the engine compartment is cleaner.

The carb is very adjustable, and the timing is as well, the rebuild kit comes with a spring and wiegh assortment, as well as an adjsutable vacuum advance so you can get cruising mileage as well as performance....AHHHhhh the best of both worlds on a car that's still faster

 

The whole point of me posting this was to show WHAT IS COSTS by using NEW items.

I'm not even going to get into the tuning aspect because tuning has more to do with a person's abilities than it does "carb vs. TBI".

 

Why am I not surprised this got transferred here?