ok I have read the budget build on this site and also read the PHR vortec build where they have gotten 447 HP out of the same engine I have. I noticed that PHR used a carb instead of the TBI unit used in the budget build and was wondering what would be the downside of using a carb instead of the TBI or the other way around? If I decided to use the TBI and already have the 350 injectors and build the engine to specs that PHR built theirs how much horsepower will the 55lb injectors be good for and would I need to get a adjustable regulator. My son is helping me with this project and he will be driving it to special occasions until he gets some driving experience under his belt. I would really like to just leave it TBI with stock regulator to keep the HP down a bit and when I think he can handle it get the TBI set up needed to have the engine perform to its potential but if carb is the best way to go and there arent any problems associated with this I will just go that route

 

Well, I throw this out there....

In my world, there is no negative to carb - That is as long as your emissions will allow it (and if I remember, you are in NC, so no issue). To me, the TBI is limited - it doesn't have the programming capability of the TPI systems (since there aren't as many variables to be changed in the prom), and there are very few folks that will even try to program for you (thus the almost need to do it yourself).

With a carb on the otherhand, the adjustments are now mechanical, opening up unlimited possibilities with a simple screwdriver. Ols School yes, but I've gotten old enough now myself where I understand the phrase "they don't make it as good as they used to".

There is alot that can be done with the TBI, especially by those willing to buy the equipment, and learn the programming, and spend months fine tuning the chips - and I applaud those that do - it's beyond my patience, time, and finances.

But for me, the carb put the control into my hands with my current abilities and knowledge, and allowed me to enjoy my tinkering instead of getting frustrated with things beyond my time, comprehension and abilities.

 

will I have to change distributor and all that also or will the same one work? I think Carb may be the way to go instead of messing with this prom stuff if there is no problems switching it over as far as getting it inspected and stuff like that (yes I do live in NC)

 

TBI gives you a million times more control than a carb, and is actually easier to work on to boot, and that's something that can't be said about any other EFI system. Carb's controls are simple because of how limited your control is.

The problem is with fuel and airflow. TBI wasn't designed for high horsepower so these are things you have to pull out of your ***. A TPI fuel pump with ramped up pressure (vacuum referenced adjustable) will take you reasonably far with 350 or 454 injectors. You can get bored out TBI units online that supposedly will take you up to around 400 hp. It's been said by users on this board that the theoretical limit for TBI is about 450 horsepower, but I don't know how many people are actually there. You will absolutely have to tune it though. It has a bad rep because of the engines it was placed upon, there's really nothing with TBI itself. There are aftermarket computers in the $350 range that make tuning extremely easy, no "chip burning" required, just plug in your laptop and burn right to the ECM. These newer computers give you better control and engine management than the stock ECMs could ever dream of giving you.

 

Now that would be great! 4 years ago when I was fooling with my TBI there wasn't sucha thing, or else no one here knew about them - I had the worst time finding anyone to program a chip that would work with my newer intake, TBI mods, LT1 cam, ported/polished heads, headers, and gutted cat and hi-flo exhaust - All I ended up with was a barely running car. So I gave up and went carb the next go round.

Yes, to switch to carb you'll need an HEI vacuum advanced distributor (about $125 new), a retrun-style fuel pressure regulator (Mallory 4309 sells for $80), a carb intake or maybe an adapter, and the carb of course. You'll also need the proper linkage add-ons and brackets for your carb for the TV cable, and a method of locking the torque converter (both asuming you have an auto tranny).