1998 bg5 legacy

[yellowsub]

hey guys im doing to the twin to single with then the next two months am useing sti v3 heads to bolt on my block is there any test i should be doing before i bolt heads on as many people have said they can just bolt? :-\

[Koom]

Firstly its spelt "Legacy"....

Are you trying to test whether or not the heads themselves are good? i.e.hardness test, getting them planed for flat surface

or just whether or not they'll bolt onto your block?

p.s. If you have a BG5b model the heads are essentially the same anyway.

[yellowsub]

have fixed tht :-[

na gonna get them checked my garge more the point of bolting them onto my block

[ReubenH]

Get them overhauled. New valve stem seals and such.

And yeah, only real difference between GTB and STi heads that i know of is the STi is shim under bucket.

[yellowsub]

oh ok is tht a good thing haven shim under bucket over spring

[ReubenH]

Shim under is better than shim over, yes. I have no actual knowledge regarding them, just that people on the forums have said shim under handles high RPM's better.

[Koom]

Shim under allows you to use cams with longer duration and more lift than shim over. Also supposed to be less prone to the shims falling out at high revs (if its really a worry, upgrade to late model heads with shimless valves). In the world that 96% of us live in, there is 2/3's of f all difference between using shim over and shim under.

[yellowsub]

so really no benfit in swiping head over then apart frm not haven the old oil pip handing out back of cylinder head ???

[ReubenH]

if you gotta rebuild, and you have the STi heads. Use the STi heads. If the engine is actually fine, and doesn't need building, don't bother, the GTB heads are more than adequate. I'm still using my GTB heads, they are juuuuuust fiiiiinnne.