Ok, so I have a stock 91 formula 305 5spd, with very minor mods that were done before I bought the car.
It has a stage 2 chip, and 1.6 rocker arms.
I'm looking for info on what else is needed to be modified in order to switch to a high flow lower manifold and runners.
Does the MAP sensor need to be changed? Is the stock injectors and throttle body ok to use. I want to start buying pieces so I swap this out one of these days.
Any info would be great.
Thanks
Brett

 

You really won't need much of anything if all you're doing is that. Maybe consider further supporting mods like headers.

Ideally you'd want to datalog and get a proper tune done, as those 'stage 2 bla bla' chips are just b.s. snake oil.

Tuned Performance (in my sig) can help you with the tuning side. You should be able to bolt and go without any grievous issues, but I'd rework the tune myself.

 

Thanks for the reply. I was pretty sure it was a direct bolt on without many other mods, but I wanted to
post just to make sure I wasn't missing anything. I will also look into having a new chip made when I
actually buy everything.

 

Base may need the fuel rail stands cut down to fit, maybe not with stock injectors but can with aftermarket if you replace them. Or double the orings on the bottom. Other than that everything else should bolt in

 

thx for the info

 

Who's Stage 2 Chip? Have you actually looked at the chip or did you put it in yourself?

I'm curious since it is a "Stage 2", what they stages maybe.

As for your base and runners, what you will need depends on which manifold you are talking about. Some will require nothing, some will require fuel rails, some will need a custom tune to really make the swap worth it. Which manifold and runners are you considering?

 

Honestly not sure, I was just told he replaced it with a stage 2 chip.
Most likely looking to get the eldelbrock high flow manifold and runners or
that with the SLP runners.

 

Those are primarily bolt on. You may want to install an AFPR as well while you are in there. It is not a replacement for a custom tune and fuel flow at different pressure isn't fully linear, but... if you find yourself a bit to the lean side a few pounds of extra fuel pressure will help the ECM. While you have it all apart, you should also consider replacing the injectors. The Multecs are a pretty common failure these days. The seals are 30 years old and were not designed to handle our current ethanol blend fuels. It's not a matter of if, but when they will have issues. I suggest spending the extra money and getting the Delphi replacements over the Bosch IIIs.

 

Thx for all the helpful info. I will do my research before buying and putting it all together.
And yes I’ve learned my lesson the hard way with the multech injectors. They do not like fuel injection cleaner, effed up the o-rings. I replaced them with the Bosch injectors.
Thanks again for the helpful input.

 

I have the Bosch... previous owner installed them. Upon all of my readings, if I had to change them again, the Delphi's are really plug an play. The Bosch need some tuning to get them absolutely right.

 

Considering the Bosch III injectors everyone has been using appear to be Ford 5.0 injectors, it's really a wonder they are as popular as they are.

 

they have a good flow pattern and open and close faster than the stock multi techs but they do need adjustments made to the voltage offset values to get a good tune. Biggest problem I have had with mine is getting information on what to use. What I have found did not match the numbers on my set. So it was a fair amount of trial and error... Another reason I like my EBL P4 ECM