Hi guys, im after some advice and opinions... i have a classic facelift v5 that i am rebuilding. I have a cdb and trying to work out which heads to go with. Im aiming for 450-500bhp (i know the manifold bolt allignment changes with the facelift engines, but i will be reversing the inlet manifold and converting the wiring to go to new age coil packs, so i am hapy to go with any version heads)

So my quesion is which heads are the best for my build?
And how do you tell the difference between the heads? (Dont want to get ripped off)

Thanks :-)

 

Depending on what ecu you are going to run then the simple option for your power level would be sti v5/6 heads, not really sure what the identifying marks are. Other option if you're feeling flush is avcs heads from a new age sti but that requires additional wiring and an ecu capable of running them

 

V5/6 STi heads with a V7 STi inlet mani and TGV deletes, new age coil pack conversion and your onto a winner id say

 

I currently have an apexi with hand controller, but thinking of going simtek so I can remove the maf to help tidy the pipework. I will be stripping the car back to have a complete bare shell respray, so anything can go back in. I think I will avoid the avcs though. Am I right in thinking the heads changed with each version? And for each version is there 2 different heads (one for wrx and uk2000 and a different one for the sti)? Or are there more options? (ie wrx are different to uk, and the limted editions, like the 555 had different heads)

 

I did read somewhere that the v3 sti heads were the best heads Subaru produced.. But then I've read other posts saying the heads don't make any real difference,. And cant find anything about what technically is the difference or how to tell the difference (I have 3 complete engines, a 1995, a 1996 and a 2000, and (apart from the stud pattern on the 2000) they all look the same to me:-) ..that's if these are the original heads for these engines anyway!)

 

The v3 sti heads have slighty wilder cams but the sti v5/6 flow the best, anyway to fit sti 3 heads you would need to change quite a bit. I agree with Dan that is the simplest and most effective option for 450-500bhp, sti heads have under bucket shims and solid lifters which allows them to rev to 8k.

https://www.scoobynet.com/general-te...-v3-heads.html

 

STi Ver 5~6 heads would be a good choice for what you looking to achieve power wise.

Can be identified by :
Off set Inlet manifold bolt holes.
Additional cam cover bolts.
Dual Thrust camshafts.
LHC 00* RHC 00* (* is a number ranging from 1 onwards).
ED3 + ID3 valve codes.
Pink Colour coded valve springs.
Under bucket shims ( can be changed to V7 onwards selective buckets if running a lot of anti lag ).

Hope this helps

Mick

 

Sti5 heads on my V5 Uk Turbo (2.1 stroked) running circa 500bhp if that helps and they are standard V5 heads but rebuilt

 

Sti version 5 heads with Jun 272 cams running 507 bhp on a 2.1 stroker

 

Thanks guys.. i'll take your advice and go V5 STI heads, V7 inlet and newage coil packs.

Thanks merlin24 for the id info on the heads

(I have some questions about the manifold, but i will start a new thread for that)
:-)

 

Did you get any better replies on facebook?

 

No,. I posted in several groups, but seems the people that know what they are talking about are on here ;-)

 

just to reiterate what banny stated that the avcs heads improve drivabillity low down where it matters for 90% of your driving.
my sc54 which is always considered a lag monster comes on boost at 3200rpm in the low gears on my 2.1.
unfortunately it also means an ecu capable of controlling the separate avcs function lol.
no one can seriously think that a 500bhp impreza is a cheap option though--do it right and do it once imho.

 

I think ill leave the avcs for budget and ease.. To be honest I'm not too bothered about drivability and even performance as it will be a show car / summer weekend car (garaged during the winter). Its a 2 door and I'm going to do a bare metal respray with a 22b kit (so alot of my budget is going to go there! :-) ) I had originally intended on keeping engine/brakes/ trans etc as origional as possible (even though alot of people have said it cant be all show and no go)... That was until I saw the clean engine bay look. I will build the engine to take 400-500, but prob only map to 300-350 and keep the td05 and 440's already on the car. That way the engine should (hopefully) be reliable and can be easily taken to bigger power if I ever want to (which I probably wont do)

 

tbh paul 350 in aclassic will feel mega fast anyhow -easy 4.5 second 60 and 10 second 100mph . the nice thing with the bigger turbos is mega in gear acceleration and a much bigger wump at the top end
had an 18g and 20g years ago.they always seemed to go a bit flat at the top end imo. quite laggy too (3800 on boost) for the power.

i beleive andy f billet version has longer legs than previous lower tech models.
old school 20g may make up to 370-400 -makes for a very nice road car. reckon you,ll need 550 injectors to get there though.

 

I had a non-billet 18g on my 2.1 stroker and it made 403bhp with 20% meth, 380bhp on V-Power and I would say it was anything but "laggy". It made for a rapid road car and was nice on track

 

I'd say v5 head's great for flow, not to impressed with the shim under bucket scenario, had one jump out on mine so at least change the buckets for later versions (no shims)

 

When I was building a forged bottom end for my v5 sti my mapper said I should fit small port wrx heads
His main comment being. Bigger isn't always better!
Given the amount of experience this guy has in building engines etc I took his advice