I'm thinking of going 2.5 block with v5/6 Sti heads but my shell is a version one will I need to change a lot of my existing loom?

 

Just fit sti 3/4 heads and use your existing manifolds, wiring etc, its just a straight forward job then. It a right pain to start swapping manifolds, wiring etc.

 

What are the exhaust profiles though I would ideally want avcs heads but I'm not sure who could wire it all in for me

 

You really need to work with the person who will be mapping it in that case, they can advise on what ecu, and how to sort the wiring out, it can be done but is alot more involved. If you want to gain spool from the avcs, you can alway run a higher compression ratio which will give the same end result. What sort of turbo and power do you want to run?

 

As above, worst thing you can do is build a mismatching engine.

Find a tuner you want to buil it, get them to spec up based on requirements and budget an then go from there.

 

im goin with a gt35 but if needs must and the spool issue is gonna be a problem ill go gt30 all i really want to know is will my existing loom be fine for the sensors on the block aslong as i use v3/4 heads or if i go avcs how much trouble is it to wire it all in?

 

You probably know this but you will need to be closed deck with 14mm studs, supertech valves,springs etc and cams to get the most out of a gt35. if you stay semi closed with 11mm studs dont go over 450bhp.
the sti3/4 heads will bolt straight on and work with your current inlet manifold etc, so all the sensors,wiring will be fine. If you go avcs, you need a v5 on inlet manifold and then you have the headache of how you wire it up, individual coils or coil pack, tps, idle control etc. There are mechanical issues with fitting a v5/6 inlet as it fouls the avcs units, it can all be done but you need to work with your ecu man.
I'm doing a similar build at the moment, its a V6 gc8 and we are fitting a high spec 2.5 with avcs heads, Steve Simpson will be supplying, fitting and mapping the ecu, so I'm discussing the spec etc as we go along.

 

are the avcs worth the trouble over ported v3/4 sti heads? or do you personally think i should just go for a smaller turbo say gt30?

 

did any of the classics come with top feed injectors? im guessing it was for version 5/6 if they did? and can you fit those rails to any inlet or only later ones anyone know this? also anyone know whats required wires wise for using v5/6 heads on v1?

 

No, all classic's are side feed and they differ slightly from phase 1- 1.5 and 2.
There is no simple plug and play option to swap inlet, harness from phase 1/1.5 (your car) to V5/6 or new age.
What sort of spec are you building the engine to?

 

I'm doing something similar at the moment. Car is a v3 sti. I'm using v6 sti heads and a newage sti inlet manifold. Work in progress but basically I'm fitting the newage inlet backwards for reverse inlet. I've cut the throttle body plate off an old phase 1 inlet manifold and I'll get that welded over the original hole on the new age inlet. This will be turned 90 degree so the throttle cable will run under the inlet (newage is taller so can't go above) . The next issue is the idle control. I've completely cut off the phase 1 idle valve base including the hidden tube going to the centre of the inlet. I'll get this welded onto the newage inlet. Then I can use the original wiring loom, changing the injector plugs though. I've got the new age fuel rails but will probably change them for billet fuel rails. I should be able to run it on standard ESL ECU.
I've only just started this today.
If you want Avcs also then you'll need extra loom added for that and a different ecu . syvecs good but pricey. I believe alcatec can have an Avcs control board added.