Scott Ruffner wrote:
> Yes, I was figuring on doing this regardless...actually, I probably
> wouldn't go with the absolute largest possible size, but would leave
> myself some room to oversize at least once should I burn a seat or
> something.
You should have replaceable valve seats installed. Then you can have
the old (burned) ones removed and replaced without having to worry about
going oversize to do the repairs. Plus they should be Hardened seats so
they handle unleaded fuel well.
>
> I was reacting to a post I saw from someone else on the list (I remember
> who) that made it sound as if the '74 had a significantly different set of
> valves (like the '76 had the flat top pistons). I'm really wondering if
> there's a particular year when the 1500 heads were significantly
> preferable for some reason. If not, then I'll stick with what I've got.
Not necessarily! I am not sure if there are differences in 1500 heads
(other than the ports for those air rails on later ones). My point was
that you can decide what sized valves you want (within the limits of the
head) and have them installed by your machine shop, regardless of what
you currently have.
>
> I am planning on CC'ing the head, milling to get the compression back up,
> then CC'ing again. I'm also planning on spending some time polishing
> intakes with the dremel. I do have a set of HS2's and an intake to match
> them with the 8 port head.
>
I haven't done any major work on my street car's head but I too am
running HS2's from a Mk3 engine and have the flat top (9:1) pistons. It
performs well!
> I'm curious what your thoughts on are putting the effort into a 1500
> engine versus the small-rod 1300? I like low-end torque, so I think the
> 1500 is the way to go, but I think I'll be changing the bearing shells
> every 30k or so. This isn't the end of the world, but I wonder if my
> effort wouldn't be better spent on a 1300 engine.
>
For street use, the 1500 is a good engine. As you say, it has better
low end torque than it's predecessors but having the longer stroke will
not yield the higher rpm that the earlier engines are capable of. What
are you planning to use it in. THe small bearing 1300's seem to be
highly preferred by racers, but there are quite a few 1500 powered spits
out there on the race tracks as well.
I am building up a Small Main 1300 for use in Tiny Tim, my autocross
project because of all the recommendations I have gotten from people I
have talked with. Smaller bearings mean less drag and so the result is
higher rpm with less effort. The shorter stroke also adds to that
equation.
Regards,
Joe
--
"If you can't excel with talent, triumph with effort."
-- Dave Weinbaum in National Enquirer
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