Reply to "what have i got?"

> i was told by the seller that this was the first rebuild - so why he went
> 40 over and not 30 over i don't know, i'll try to find out

The block may have been heavily worn and out-of-round, requiring that oversize
to clean up properly.

> peak torque of 475 ft lbs happens at 4,908 rpm
> peak hp of 491.8 happens at 6,301
> i think the dyno numbers show it is meant to run more around the 4,000 to 6,000 range...

For best acceleration, you shift approximately 500 RPM above the HP peak.
That's 6800 RPM for this engine. Given the 3.75" stroke, that's the
equivalent mean piston speed of 7000 RPM in a stock stroke 351C.
That's sporty for a street engine but as long as it pulls well in your
normal operating range, shouldn't be a problem. If, as I suspect, your
engine was tested with dyno headers and no mufflers (or efficient ones),
your engine, as installed, may make less power at a lower RPM. Typical
Pantera mufflers can lose 50+ HP on an engine like yours.

> when i called the head mfgr, they said the chamber size for the ported version
> is 78 (even though it says 74 on the website) - what does that change in your answer,
> if anything?

It means your compression ratio is slightly lower.

> if there is, does that take care of the "mismatch" issue that George points out?

Yes. It's hard to judge by the picture but the ported version of the heads may
have a larger port size at the head and your builder may have port matched the
manifold so the smaller intake port falls within the larger head port. If so,
the adapter plate isn't required. Not optimal but, in our dyno testing of 2V
intakes on 4V heads, the Air Gap 2V still worked pretty well that way.

> "Moroso stock depth pan with internal slosh baffles"

If you corner/brake/accelerate hard, that pan will be insufficient. When
you are shifting at 6800 RPM, you'll pump a lot of oil to the top of the
engine. What's left in the pan can slosh away from the pickup under simultaneous
hard braking and/or cornring. A gated and baffled Pantera road race pan is
what you need, Armondo makes a good one, as does Aviad.

> An inexpensive Damper option is the Powerforce+PLUS Series 9000 SFI APPROVED damper,
> Part No. D-90006.

That's a cheap Chinese damper trying to pass itself off as a quality part (the Powerbond
damper from Australia). If you google up guys who attempt to drag race with them, you'll
find a number who have suffered failures. The real Powerbond, Romac or ATI are better
parts.

Dan Jones