sifting through some of these replies has given me a lot of good information, thanks guys (even the negative stuff is appreciated)

by building a boost friendly a-series, i intended to fix the tune, injectors and other obvious problems also, not just try to build a titanic block

speaking to the turbo guy he was quite confident turbo size is not an issue, he did port out the wastegate as i told him i had too much boost, but i will be waiting for the second turbo he fixes to be ported aswell to match

yesterday i picked up a pulsar a-14 head, this looks to have a very open chamber and should be good for lowering compression (will get picture, not sure on effects to squish )

the talk of injectors maxing out leading to detonation which is damaging rings has been really helpfull

anyway this has been a good thread, im sticking with twin turbo, but it could be some time before this setup makes a comeback, especially if the ute sells i wont really have a hole for it


to answer some smaller questions:

-i've never pulled out white plugs from the turbo setup

-all motors have used stock CR, and essentially been stock internal, the two a15s were practically fresh rebuilds, the other two were basically dead when i started with em

-"how many more engines will it take before you realise that twin turbo setup is fundamentally flawed?" AT LEAST FIVE TO TEN i'd love to hear your explanation of that theory (i have dragged off modified wrx's, skylines and 250kW plus commodores) its got potential as long as i get it half reliable.

from this thread i have learnt, as some people have said recently, getting it tuned right is more important than anything else

im still keen to make a decent block for it, and hence why i asked the questions