Right ill start at the begining i have a 93 wrx import it was running 310bhp with printout when i first got ut to my knowledge the mods were 255lph walbro fuel pump td05 not sure what g it is though ss headers kakimoto decat exhaust k&n filter. The headgaskets went on the old engine and a friend of mine just so happened to have one a spare kicking around so changed the block over with the heads everything else was original but now its not got nearly as much power after speaking with someone else they suggested it might be as simple as a boost pipe on the wrong way round is there a way i can test the system to find out

 

Wouldnt care at all about rolling road figures, unless it's the same rollers on the same day!

Get it on some rollers and compare the graphs not the figures. See if there's anything suggesting there's a problem, like really delayed torque or power tailing off too early.

 

With regards the vac line arrangement I would post up a pic showing how its all arranged

 

Ok will get a pic up tomorow

 

Have you got a boost gauge?
What boost was you hitting on the old setup?
What ECU are you running,ESL,Alcatek?

 

Are knackered Subarus faster?