rml:
I agree with all your comments. I would add this remark:
While the late model cam is wimpy, it is stouter than the early
TR6 cam. The early cam was 240 degrees, the later cam is 256 degrees
(The GT6 cam). The factory had to go to the more aggressive cam because
the lowered compression ratio due to emissions was sucking the life out
of the engine. They had to start putting some of the better bits and
pieces in the engine to make up for this. Hence the better flowing head,
the dual exhaust and GT6 cam.
If you can mill the head to get the compression ratio back to
about 9.5:1 or so, the later motor will make more power than the early
motor (about 10 HP or so) with no other changes. If you do mill the
head, you will want to swap the pushrods from the earlier motor, as they
are shorter and will make it easier to adjust the valves.
You might also consider converting to the later dual exhaust, although
this is enough work you might consider an aftermarket system as well.
The stock BL muffler is a real bottle neck for power.
Vance
-----Original Message-----
From: owner-6pack@autox.team.net [mailto:owner-6pack@autox.team.net] On
Behalf Of Robert M. Lang
Sent: August 08, 2005 11:23 AM
To: michael lunsford
Cc: 6pack@autox.team.net
Subject: Re: Which engine to rebuild
Hi,
<snip>
But if your goal is to keep the motor one way or the other (early vs.
late), you should def go with the late motor. It's got a better head and
it has all the "improvements" and the only drawback is the wimpy
18-58-58-18 cam (at least I think that's the cam timing.) The late cam
for
Fed. Spec. cars is pretty wimpy... so plan on a regrind to make some
power
(or pow-wah as we say in Boston). Oh - if you have to rods out for
"sizing", get 'em crack tested and have them pay particular attention to
the holes drilled through the rod at the upper end bolt for cracks. If
your goal is to lighten and polish - crack test and use the early rods
if
they are okay.
regards,
rml
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