Completely possible, though the mechanical clutch linkage might be tough. According to TTI's website the Z-Bar will hit their headers.
Basically to install a manual transmission behind a 6.1L Hemi, you need to buy the appropriate 10.5" flywheel, pressure plate, clutch disc. The clutch disc must match your 18 spline or 23 spline input shaft naturally. You must also install a pilot bushing in the end of your 6.1L crank. To do this you must use a die grinder to carefully cut out a ring pressed into the end of the crank. A die grinder with a rotary file should do the trick. Try not to score the crank with the die grinder.
Here's a flywheel:
http://www.modernmuscleperformance.com/5_7L_6_1L_HEMI_Steel_Flywheel_p/p5153592.htm
A standard LA small block bell-housing will bolt up to your hemi, simply leave out the top bolt. Since the offset is .060" different between an LA small block and a Hemi, you need to take a grinder to the input shaft of your transmission and take about a .100" off the end.
Since the clutch, pressure plate, bell-housing, and transmission are all standard 4-speed parts your Z-Bar and standard throwout bearing will work fine. Thus, any aftermarket hydraulic clutch designed to work with your 4-speed should work fine.
Here's an example of one:
http://www.hotrodhydraulics.com/MOPAR-Product.htm
Finally Passon Performance APPEARS to shipping the first few orders of their 5-speed. The buzz about the transmission is generally good. Main benefits include superior strength and a drop in, installation.
Regards,
Joe Dokes
