[Amc-list] I6 Cams

["John Elle" <johnelle@xxxxxxxxx>]

Tom, 

I'fn I had to pass smog again, as this selection was based on the desire to
not futz with things come smog time, but drive it in and drive it home and
let the ignorant 1980 vintage electronics adjust the carburetor rather than
me I would use the same cam again. 

Iskenderian 256 Supercam w/ rpm range of 1500-4800 rpm, intake/exhaust valve
lift at .450/.450, duration 256/256 degrees with .050 duration of 202/202
degrees and a lobe center of 111. A lot of the happy idle comes from 111
degrees and is also a lobe center that is a recommended spec. for fuel
injection operation. 

I'fn passing smog no hands was not a concern I would step up to the
Iskenderian 262 Supercam w/rpm range of 2000 - 5500 rpm and a  .445 lift,
262 duration and 109 degrees of lobe center and then use an Edelbrock 500
cfm 4bbl AFB. 

Of course Iskenderian is just down the road a piece from your place and I
have always found them to be customer friendly and it was cool to just stop
buy and purchase a cam over the counter! But it has been a few years since I
have done that. 

I bought this cam in 1996 and I believe Isky has maintained them selves
along with current technology so it might pay to ask them what new cams they
may have for us old engine guys! I really can not compare the performance to
other cams and I am sure that there are a few other manufacturers out there,
but then again, never had a reason to NOT purchase an Iskenderian cam. 

My 74 TSM shows the 258 as developing 110 brake horse power at 3500 rpm and
a torque of 195 @ 2000 rpm. A 304 develops 150 hp at 4200 rpm and 245 ft lbs
of torque at 2500 rpm. Compression would be about 8.3:1 stock. Mine was
massaged to get 9:1 by milling the head and decking the block. This let me
stay 91 octane compatible. 

A chassis dyno run when the rebuild was about a year old and I was still
using the Stock CARTER BBD set up and a full smog tune showed a rear wheel
horse power curve that was fairly flat beween 3000 rpm and 3500 rpm of 91 HP
at the rear wheels but as the readings started at 2700 rpm, the torque
readings were already started down from where ever the peak was at and
started down with 170 ft lbs of torque. 

I have never had a problem running a "tall" rear axle ration even if the cam
specs indicated that the recommended rear axle gear ratio was in the high
3's or low 4's  The guys running the chassis dyno were impressed at the
time, even it it was a lowly I-6 and then told me that the numbers I was
getting were almost on par with Buck 3800 numbers. And that is not a bad
part of town to live in. 

When comparing numbers keep in mind, that mine were developed and read off
of the rear axle. 

Later

John

 

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