wufido

hello, My friend has a 98 expedition 4x4 4.6L, its pretty much a daily driver...he's got 24"s on it and a custom built system that takes up the entire rear and lost of electronics like tv's and other audio components....so its a heavy truck....it seems that in the past 6 months it got really slow...the engine revs and sounds normal but I suspect its got alot of blowby because when it downshifts under acceleration the rpm's climb very slow...tranny shifts fine....I was doing research and trying to figure out how hard it'd be to put a lightning engine..5.4L supercharged...so here's a few questions for those of you who do know about it..

1. Is it worth the time to put a lightning engine??
2. will the tranny hold up to the power or would it need something beefier?
3. is the cost too high to do it?
4. would it be best to buy a rebuilt 4.6l and supercharge it?