I am looking for opinions and actual experience with tuning on stock LO3/LO5s or TBI 454s. Just curious if everyone feels that the upper RPM breathing problems are due to restrictive heads and lame cam or very conservative tuning. (I realize the combination is the major problem, but is one worse than the other)
I have changed lame cams out of carb cars and noticed a huge difference, but with swirl port heads, is changing just the cam enough? (Will a well tuned, cammed, swirl port car rev well, or are better heads 100% necessary?)
I am ready to make the investment in a PROMinator but want to be sure I will be satisfied with the results. I have invested enough money in bullsh!t “performance” parts that I am worried I won’t get enough bang for the buck. I want to stand on the pedal and have it pull to 5000 grand.(It actually runs better only using half throttle) Can that happen in a well tuned LO5 with small Comp Cam and swirl port heads?(raised fuel pressure, better fuel map, better timing map) Or am I asking too much of this combo?
If anyone thinks of better search terms than “stock tuning” please let me know, I got the book with that one.

 

They are both poor in stock form. The tune is only bad because the parts that it is controling are equally weak. That is not to say that there is some significant improvement to have when getting into chip work on a stock motor. The only way to make big power with a TBI is to rid it of its stock heads and cam. They are junk to say the least and offer next to nothing as far as performance is concered. You will only feel a difference with your new parts if you tune accordingly. If not the stock tune will be so far off your car will run like poo nuggets. Chip burning is really necessary with any serious mods on a TBI set-up to make it run the way it should.

 

SNORK!

Shifty said "POO NUGGETS!"

Sorry... I'm a bit slappy after this day at work.

 

What shifty said is true. Most tbi engnies run like "poo nuggets" because of the "crappy" parts. Once you replace the "crappy" parts your left with a "crappy" tune running your awsome parts. You really have to be able to tune your vehicle if your going to make any power, or have any type of drivability that FI is capable of.

You wouldn't dream of adding a crap load of speed parts to a carbed engine without changing the jets. So don't do the same with FI.

 

Thanks, I was just curious if anyone made major gains with tuning only. I think most start tuning because of hardware modding.
I thought Dewey and JP have done some tuning on stock TBI's but I'm having trouble finding those posts....
I know that recurving and jetting a smog era 350 will wake it up, but wasn't sure if it works the same on a swirl port motor because the hardware is so bad to begin with.