How much more horsepower could I gain from an aftermarket intake manifold and plenum that lets me use the twin-blade throttle bodies?

 

are you talking about the bullit manifold? if so 5-7rwhp is about it with stock cams. with cams you can gain more. its really a nice manifold with a good set of cams to take advantage of the flow it can support.

 

While I'd love to get it, it's far too expensive. I was thinking one of the ones from Sullivan Performance. I don't know if anyone knows about Sullivan Performance, but they have some awesome products. Like intake manifolds that you can put on a 5.4 and use under a stock GT hood. No longer do you have to get custom work done to do a 5.4 swap, and their prices are really reasonable too. I recommend everyone check them out: http://www.sullivanperformance.com/index.htm

 

No no dont get that sullivan intake. That thing is made for a race car or at least high boost. It has such short runners that your car will run like a dog with your stock heads. The best one in my opinion is the bullit manifold because it is a ford piece, aluminum, and makes power with a long runner design. You can get the P51 but it costs just a couple hundred bucks cheaper than a bullit. It may make more power than a bullit but not much. Plus its aftermarket so theres always issues with that.

I say get the bullit but buy steeda fuel rails for it. That would look racy.

 

i never seen anyone make good power gains with the p51