Hi John,
Its both a pump gas thing and a cost thing.
Keeping the CR under about 11:1 with aluminum heads
lets me get away with 93 Octane (with a little care
not to mash the loud peddle below about 2800 Rpm),
and makes the assembly a little longer fused between
freshinings. I HAVE goten away with 10.5:1 with
iron heads on pump gas too (the 273 Commando in the
Barracuda), but I finally goaded that motor into a
spun rod bearing in September (sigh). Oil starvation
and 36 years of abuse fainally cought up with it. The
rod stayed on the crank and the motor made it back to
the garage, but its done until it makes a trip to the
machine shop. A steel (273) cranked 318 is going
together in the mean time (started that motor back in
July, just not quite done yet). Hopefully the 318
(actually about 324 Ci with a 0.030" overbore) will
last through SCCA drivers school in about 3 years, by
then I'll either have the 273 back together, or (if I
hit the lottery) a destroked 340.
Anyway, I don't have a trailer at pressent so
the motors and gearing are not going to be as tighly
wound as they might otherwise be. The 318 will have
9.75:1 +0.030" KB pistons, Hughes Engines mechanical cam
(2700 I/2770 E duration, 0.560" I/0.575" E lift, on
1060 lobe centers, Hughes lists this cam for 2300-
6000 Rpm), Hughes light weight lifters (88g vs 123g
for stock), CompCams Magnum rockers, some porting
(1.88" I/1.60" E valves), Edlebrock Performer RPM intake.
Everything else comes off of the existing 273 and
bolts right onto the 318: 650 vacumme sec' Holley,
Chrysler electronic ignition, 7 Qt road race oil pan &
pickup, valve covers, and Dougs Headers. It SHOULD be
good for a few ponies over the VERY tired 273. =8^P
The SCCA/SOLO II rules for CP engines are pretty
wide open, with the limmiting factors being the weight/
displacement rule, a limmit of either stock intake or
a single 4BRL carb of not more than 1" and 7/8" throttle
bores, and the production block. There ARE 13:1 motors
competing but I've found that more than enough power can
be had for cone killing on pump gas. The NEXT motor for
the Barracuda, be it 273 or destroked 340, will be around
12:1, as I don't want it to fall on its face above 6600
RPM the way a lower compression motor can.
At 10:49 AM 10/29/02 -0500, you wrote:
>
>Very interesting motor spec's - you can run Alu. heads but only 10.85:1
>Compression?
>
>Are those the rules or are you trying to run on pump gas?
>
>
>
All the Best! Dave ;^)
'66 Formula S Barracuda, CP/Vinatage
'66 C code Mustang Coup, CP
'91 Sundance, HS (150,000 miles and counting)
'97 Cherokee
Lame Horse Racing
College Park, MD
http://www.erols.com/dmapes/
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