Speed Density to MAF

i have a 1991 gand marquis with a 5.0L i want to build the engine a bit, but to do so i cant use the speed density system unless i want to get a chip re done every time i do somthing to the car (i.e. cam) can anyone point me in a direction? i know it can be done my buddy has a late fox boddy mustang with the MAF conversion (he bought it that way!) any help would be greatly apreciated ~Jeff

You will need at least an airmassmeter and a chip, in worst case you need a new ECU.
Why don't replace it with an aftermarket system instead?

this would be an aftermarket system... i would be changing the entire intake system from a speed density system to a Mass Air Flow system. there is not a "kit" that you can just buy and put it in (at least that i have seen)

Spend the money on a system like Haltech, Autronic or similar instead, which you can remap yourself. You can also use an UEGO sensor with it and this allow a better lambda control.

MAF and Speed Density work different, with MAF airflow is used as a measurement on load while most Speed Density systems use throttle position as load and MAP as correction. Load and engine speed is basicly what is used to get the amount of fuel. Often this value is lambda corrected at low load/speed.

After changes to the engine diffrent lambda values might be needed. Ignition might also need a change if ignition is controlled by the ECU. So even that MAF system can handle bigger changes (usually most speed density systems can adapt) this should not be seen as a complete solution.

In high performance engines speed density systems are mostly used, mainly because hotwires or flaps are restrictive, slow and can be fooled by a hotter cam.

im not looking to tunr this grandma car into a 10 second boat... im just looking to get a little "more out of it" the car only devlops 150hp, but it makes 270 ftlbs of torque(at only 2000 rpm)... i want to keep that torque but gain some hp... i have re-built the engine allready... oh well... maybe i should just "un-plug" it all and stick a holley up there!

There are a shit load of aftermarket SpeedDensity-MAF conversion kits for 5.0L ford engine. Prices run from $400-600. Ford Racing, Granatelli etc.., all make them. Your in a tough situation cause it's a very expensive upgrade. that really adds no hp. But what it does is allow you to add parts and the MAF will adjust properly for it. Your theory on changing a cam in a SD systems and reburning is totally wrong. The worse thing on SD is a cam change. Speed density works on the engine's vacuum pressure which will be totally fucked if you change cams. MAF works on barometric pressure so it is fine.

first off you want to get a new block or fly cut your pistons.....performance heads wont work with the non h.o block(no valve reliefs). You can use any 5.0 h.o. block. second speed density does support performance mods they must be done right. You can put a cam in the sd motor but it needs 114 degree lobe seperation angle any thing less and you will have idle issues. A good sd cam is a crower 15511. You can also use heads and an intake...but you will need adjustable fuel regulator....
A good set up for you would be:
E7 heads off a mustang they are real cheap
looking for more power try thumper ported E7's
Use an intake off a mustang to flows better and bigger tb
If you want a cam crower 15511 is good or 87-88 mustang cams
Anyways check out this site it might help you on you decisions
50tech online ------ Great speed density site
Hope I could help.......Jake