> Brian Young wrote:
> >
> > Hello everyone,
> >
> > Recently someone posted a list of the different types of heads for
> > 2000 and 2500 motors.
>
> Snip
>
> > Does anyone
> > know if these heads can be interchanged and, if so, should I expect
> > any difference in performance.
> >
> Date: Tue, 14 Jan 1997 16:17:58 -0700
> From: "Aaron Johnson" <sugar@holly.colostate.edu>
> Subject: Re: cylinder head interchangeability
>
> I believe the heads from the 2000 and 2500 six cylinders are
> interchangeable. There are a few problems with the early 2000 heads. They
> are very poor breathing and this problem was fixed when the move was made
> to go the 2500 in the 250 and 6 ranges. So aside from that small problem,
> they should bold up just fine.
>
> Aaron Johnson
> 72 TR6 CC84967
The early 2000 heads (GT6 MkI) won't work because they use
smaller studs and the ports are different. Heads from GT6+
and later have the staggered ports and use larger studs.
Unfortunately, there were some changes during the production
run of the GT6 Mk3. When they lowered the compression ratio
to try to meet emissions standards, they went to a domed piston
and a different head. If you put GT6+ or early GT6 Mk3 head on
a 2500 with domed pistons, you could end up with a really
outrageous compression ratio. I exchanged some mail with Nick
and with Paul Gordon on the brit-car list on this subject. I
will look around and see if I saved anything pertaining to
commission numbers. There is also some info in the Triumph Tune
catalog if you have access to one of those. Let me get back to
you on this, I don't have my files handy.
Dave Fain
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