Re: [AMC-list] Cam specs

[tom jennings <tomj@xxxxxxx>]

Nick wrote:

I scanned through a few of the posts on cam specs and such.  Was it ever
> said which engine, car, stick or auto, gear ratio etc went along with this
> discussion?  Making a general rpm range or power use across the board is
> impossible.  There are so many factors involved when deciding on the right
> cam that you can just say, here is the lift and duration of the cam I have
> that is rated at x but it doesn't perform well.
>


Hi Nick,

First, I screwed up entering cam data and got a totally fouled curve.

I know precisely what I want and where I want it.

'63 American, what, 2700 lbs?

3.78 axle, 26" tires, 3 spd + 0.7 OD.

The old 195.6 OHV engine, NOT the new six (as a lot of people read in) the
old boat anchor.


The kind of driving I'm tuning it for, 1500 - 3000 rpm, is where I want some
gain. First gear isn't that useful, too slow to shift in busy sections, and
too low overall ratio. No other transmissions available without serious
surgery.  I found myself using 2nd and 2nd-over in the tight stuff because
of the speed of gear change. I've got the standard 2nd gear (not the "twin
stick" ratio) so 2nd-over is 85% of 3rd (1.14:1) so it's good.

An "RV" type cam would be perfect for me. The other, more traditional choice
is to make power up where most people do, 3000 - 5000 and change my shifting
regime and maybe tires or axle. But that's too expensive for me, plus this
is a daily driver, the factory setup is SWEET for overall driving and the
new cam is 100% compatible with that. Plus it would be a shame to ruin the
character of a Twin Stick hardtop American.



Using the same software, I did what-ifs with the usual work, and found that
even mild things like pocket porting have nearly no gain for me at the
speeds I'm turning (though I doubt their software is prepared for the truly
awful valve pockets in this head, they are as bad as a lawnmower and I am
not kidding).

It does seem to indicate that headers would be a HUGE improvement, more than
the cam, even. I've been thinking about what it would take to bend my own
out of really skinny pipe (1.25") and really long (40" - 48"). There's room.
I am every unlikely to undertake that this year, but it's nice to think
about.
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