Jerry,

Chris was a little too strong in saying that cowling mods are a must.  I did it without required mods.  The starting point was an IO-360B1F.  The pan was replaced with one from a B1B (aft facing fuel injection servo).  Performance Aero Engines mods that sump to put the entrance on the front.  It is true that you need a custom exhaust.  Mine is a four-into-two-into-one that exits on the pilot side.  The crossover is under the much shallower pan.  The only reason I had a cowl mod is that I wanted to have a Legacy style tunnel exit and I wanted the total exit area to be smaller.  The cowling sides were unaffected.  The larger question is how much benefit is to be gained by forward facing induction.  Before you change anything, observe what your engine off manifold pressure is and then immediately go fly.  Try to find a nearby place with low enough elevation that you can safely fly, flat out, at your field elevation.  Record what your highest manifold pressure is at that time.

Pipe up right here Grayhawk if I am wrong, but I think the theoretical maximum ram air pressure gain obtainable is about 2" of mercury.  So if you record more than an one inch of MAP above what you had before engine start, you already have a pretty good induction system.  Getting more is really tough.  When you move the servo forward there is very little room to have an expanding air box to convert that high velocity air into increased MAP.  The updraft actually does pretty well, even though it looks like it shouldn't.  With a great deal of effort, I have built an expanding airbox on the front of my engine and I do get between 1.5 and 2 inches above ambient, but it was a huge amount of work.  It is definitely producing some speed increase.  Hard to tell how much, because the airplane is in the middle of many drag reduction mods and half un-painted right now.  Too late for this year's racing season, but there is always next year.  BTW, in the current, very dirty configuration, I get better than 210 Kts flat out at 2700 on 180 HP at 4500 DALT.

A lot of my original forward facing installation is available by searching the archives.

Tom Thibault
N4XB

Randy,   Yes, there are several alternative systems.  Superior used to make a composite one, now changed to metal, and there are a couple of other alternatives.  My question was on the impact of using this type of induction is a 360 cowling.  Chris' reply answers that by stating that the impact on both the cowling and the exhaust system is severe.  I will have to stick with vertical induction.   Jerry