Conversion Kit $1250
8v cyl head $350
Mods to top of block & head & fly-cut pistons $500
Oil hose & "T" piece fitting to feed the head with oil $65
Make up breather/oil drain/oil filler $50-100 depending on how flash you want it to be
an extra thermostat housing, some hose & some hose clamps $50
modify left hand engine steady bar $50
extractors, or turbo manifold & dump pipe is $450
Pistons, crank bearings, oil pump, gaskets & seals, a clutch kit, gearbox overhaul parts rad clean out, water pump etc , & engine build labour costs are simply all the same as per std mini engine build
An Inlet manifold plenum chamber to run either a carby or single throttle body fuel injection will cost about $350
If going ijected then an Adaptronic sequential computer is $750 wiring it all up & tuning can cost up to about $1500
if adding a turbo then you`ll be spending about another $1400 for athe latest model you-beauty Garrett ball bearing jobby

& you can spend from $50 upwards to $1000 for a decent intercooler
If anyone would like to check the costs of the mods to the engine block then ring Cooparoo engine centre here in Brisbane as they`ve done them & have another 3 blocks of ours there at the moment being plugged, surface milled, re-drilled & threads tapped.
So , comparing to a std mini engine build--> it`s about an extra $3500 plus whatever fancy stuff you want to add along the way...
You could spent $35,000 easy enough if you wanted too tho,,, just buy a K1200, have it fully worked with larger valves, ports & cams etc, stick that ontop of a big bore block with long stroke forged crank, custom con rods, forged pistons, Straight cut close ratio gearbox with limited slip diff, lightened flywheel & back plate assy, grey diaphram, button clutch, romac alloy harmonic balancer, alloy rad with electric water pump, fit up a T28 ball bearing turbo with fully mappable sequential engine managment system & all the goodies like cam & crank angle sensors & coil-over ignitors etc etc etc, spin it to 10,000rpms with 25lbs boost & have close on 300hp if you`d like
or you can just do a little small bore cheapy with carby & dizzy & spend about $3500 all up doing most of the work yourself.
This is just a rough guide , exact costs will vary depending on your own particular engine build specs & who does the work for you.