i would just speak to s1 john he has the following forsale cheap
woszner forged pistons £100
pec steel rods with pins bearings bolts ect £200
mint block machinced for pistons ect mint £80
mint condition fully balanced crank thats fully polished ect £80

so thats a top spec bottom end for like £450 then spend 200ish gaskets and bolts and 350 porting your head and £300 on a cam kit and you have a top spec engine.

then £500 stage3 t3
max £1500 management fully fitted and mapped

this will be a very strong 250bhp all day long

for £3300 all in