I have a 94 Gt Mustang that has had a little work done to it so far. The boy I bought it from had an aftermarket cam put in it, had the heads ported and polished. He also had the heads shaved a little. My question is.........Would having aluminum heads with roller rocker arms installed help it enough to justify doing it. If it would, how Much would it help? I am not exactly sure how much life and duration my cam is running, but it idle pretty rough. I believe my compression is about 9.5 to 1.racing okorder.com/... they have part specifically designed for improving performance on your Mustang. mixing a variaty of parts from defferent manufactures does not always increase performance. cams, heads, lifter, rockers, fuel system components need to be match for the type of performance increase you are looking for and at fordracing these parts are matched into different performance improvement types. Check out the web site it will get you started in the right direction for what you are looking for.Good aftermarket heads will often out-flow ported factory heads right out of the box. They often have better valvesprings, retainers, valves, etc. The valvetrain is often set up to use whatever cam you specify. You can also get different combustion chamber sizes to change the compression ratio. The rule of thumb is to bump your compression ratio up 1/2 point to 1 point (9.5 to 10.5)when changing to alumium heads for a given engine setup. Aluminum sucks more heat out of the chamber, which requires a compression increase to compensate. But it isnt as easy as plopping a set of heads on. You need to carefully determine what valvetrain parts to use on the heads, what chamber size to run, will all accessories and manifolds bolt up, intake runner size, port flow data... etc. Typically its best to call the tech line of the head mfg and have a long talk with the tech engineering dude. Choosing the proper setup is the differance between a really fast car and one that can be outrun by a fat kid on a tricycle..If you go to roller rockers you should do it with the cam and lifters as well as the valve springs so they all match Just adding aluminum heads with roller rockers is like a fish with-out a bicycle! It doesn\'t make any sense. It all has to match up or you get problems instead of freer movement........and that\'s what rollers are about ......freeing up the drag caused by friction in the mechanical valve train.Well using aluminum heads would be enough to justify doing it because i have aluminum heads and im at 11:1 compression. These heads are 9.5:1 compression with 11:1 compression with twin turbos. Now you are running with straight motor and shoud be fine. Now if you are going to get that pony a supercharger I would suggest getting cast iron heads with a chrome finish to manage this power gain. I have had these for about 40K miles and are still fine. I will eventually change to cast iron with a chrome finish. Hope this helps.I also believe that the primary benefit of aluminum heads is weight savings...you can port and polish iron heads just the same. I also know that aluminum retains and dissipates heat differently than Iron.Other related question