depends on how well you tune the carb. using holley parts means limitless tuning from the accel pump to the jets to the power valve. that being said, a 4bbl commander setup lets you use a carb style intake more choices and prolly better performing) and gives that carb'd look while still having great drivability. they also use common sensor parts so replacing stuff is cheap. my pro-jection setup used gm map sensors, etc.

 

I personally have never done the EFI swap, but from what I repeatedly hear, I think youll just be asking for a headache and wont get anything in return. The majority of people I hear that do the swap are happy with it, but dont get any more horsepower, and usually have WORSE gas mileage with EFI.

 

If you have a doner car then most of the parts are there. As for the aftermarket, yes most of the systems use gm style sensors, FAST, Excel Gen7, Holly, etc. I've intalled the first twoand they all these GM sensors,the sensors are cheep and the guys that have developed the software just tell me that its just easier to set the map curve for a standard sensor for all the manus. If you don't have the harness then stay with a carb setup. The new ones are very reliable and no tinkering.

 

I think what I might just do for now is go with a demon carb. later on if I want I can convert to EFI. What I don't want to do is the half EFI conversion out there. Some of the Holley and other systems are just a TBI setup which is really nohing more than a computer controlled carb. If I went EFI I would want to go with a true multiport sequential fuel injection setup which would mean getting a pretty good donor setup or something like the Edelbrock Pro Flo EFI setup. I think though for now a nice strong engine with aluminum heads, demon carb and roller cam setup should get me where I want to go!

 

Just be carfull of demon carbs. The big engine builders up here have nothing good to say about them. I haven't used them but they say they are bad for any street driving. There suggestion for my 351W is a 3 circuit carb (CSU for me) setup for good street and strip..

 

No real power gain from EFI unless the carb you have is junk, too small, too big, not tuned right. Its good for driveabilty and cold starts and you will get better mileage. Unless I want a car to get great mileage, like 30mpg+, I dont mess with EFI, because a Carb will make just as much power, and its ALOT cheaper..

So your friend is running a TPI then.. I bet its a 305 and he is talkin about how he has 400hp from it..lol. Inside joke to the 3rd gen F owners. That TPI works good for low end torque, and gets okay mileage, but they suck for making power. An LT1 intake swap would work good for him, or a complete LS1 swap. Have friends who have done those, but he wont be impressing many with a TPI, just ricers and slow cars.

Unless you need to get great mileage and want to tune with a laptop, just put a 750 holley or Demon on it with Vacuum secondary and swap the secondary springs around untill it opens fast but doesnt bog. I start with the lightest and move up on them.

The fuel rails for the 5.8L and the 5.0L might work, there is a line between them that would be longer for the 5.8, but the wiring, injectors and everything else would physically fit. A truck EFI intake wont fit under your hood. Some bigger injectors would be nice for the power you are wanting, so you would need an upgrade there. The stock fuel pump wont do the job either, need an upgradeed pump. ECM from a 5.8 or 5.0 should work, same firing order on the late engines.

It can be done, but its gonna cost you an arm and a leg. And a carb will work pretty well under the right conditions to get mileage. The 70 GTO outside has a 455 on it, with an overdrive trans and 2.93 highway gears it would run 13.50s @105mph, and cruising on the interstate it would get between 20-23mpg, a best drafting behind a truck on I40 through Tennesse got me 25. Your buddys 3rd gen would be hard pressed to give that kind of performance. Especially when I had a grand total of $6000 in the entire car, including purchase price. to put EFI on that car will cost me $3500, and the carb was $400, the intake $200. The math is easy.. tuning is key.

 

i have a speed demon and i like it better than a standard holley.