|
Hey RJ et al,
I never felt like my 325 HP 396 had any real power
even
with it's 4 speed m-20 and 3.08 posi rear. I
saved/dreamed
of aluminum heads. I WAS going to go with stock
date
coded factory aluminum heads but many people told
me
that they can be difficult to find parts for and they
would
NEVER flow like a modern set of aluminum
heads.
After 5 years of dreaming:
Finally built up my '68 SS Convertible's 396. I
used
Edelbrock Aluminum Heads, Crane Cam #286,
Forged
aluminum pistons and Scat steel rods, and a steel
crank
shaft (4 bolt mains). The intake is a matched oval
port
Edelbrock Aluminum "Air Gap" manifold.
I'm using 100 cc heads, and told the engine
is developing
9.5 to 1 conservatively-9.45. Somewhere in there.
(That
doesn't sound very technical but that's what I was
told.).
The engine was origional '68. It's .060
over.
12" 1LE Camaro Z-28 front slotted disks w/ Caprice
SW
spindles, Global West bushings, and quick turn ratio
GB.
A BeCool aluminum radiator keeps things quite cool.
Eaton
Posi & Hotchkis 1 inch lowered
springs, KYB shocks, and a
4 link suspension with a 7/8" sway bar get the HP to
the
rear wheels.
The a/c and 6 speed will be a dream
for The Future!
(Yes, I know rectangular aluminum heads would be
better
choice but I didn't have the extra $250. for another
intake.)
I already had the oval port intake situation w/ origional
oval
port iron heads FROM BEFORE.
Expensive build up cost way
over $6200. that the shop charged me
over the cost of crank,
rods and other parts I brought
them.
Horsepower was dyno'd at 310 @ the
rear wheels. A
guestimate at flywheel was figured at about
390-400HP.
They figure +22% loss through the driveshaft
& differential.
Southard Machine of Bronson, FL did the machining
work
and afterwards Rollins Automotive in
Gainesville, FL did
the assembly. It took almost 5 months
turn-around-time.
After rebuild I expected 425-450 horsepower at the
flywheel.
I was surprised at the lower horsepower rating than what
I
was expecting. I was told by Rollins that the
exhaust was
too restrictive and my Holly 670, while a good street
carb,
was too small and a 750 DBL PUMPER would be a
much
better choice for performance.
The subject of a numerically lower rear end gear was
NOT
discussed because this is a street car and gas is
expensive
enough at 12 miles to the gallon. Awwww, if only I had
a
six speed or a Gear Vendor Overdrive Unit!!
The pipes were too narrow, the mufflers too
restrictive,
and my left side ceramic coated aluminum header
(an
old Dynomax unit from before they were
discontinued)
should be replaced because it had at least 30%
restriction
from making hard contact with
driveway humps, and tall
speed bumps, etc.
I was told if I change out the headers for some
Hooker
Headers, get a good 3" exhaust from Pypes
Performance,
and change out my 670 for a 750 Holley I could be
making
a good 40 more horsepower at the rear
wheels.
The car is easy to drive now. It's not like I have
traction
problems unless I want to. Also, passing can be done
with
confidence. Rather than wondering whether the slacker
in
the lowered turbo Eclipse is going to speed up to avoid
my
being able to pass him only to slow down to stay in
front
as an offensive--That sort of thing no longer happens.
My
Chevelle comes on so strong that MOST "would be
racers"
don't even try beyond the first
peddle mashing effort. I still
won't try a late Formula Firebird (T/A), Z-28 or
Corvette,
BUT I"M HAPPY WITH WHAT I GOT HERE. Except for
one
little thing:
Even the stock 375 HP 396 GM starter isn't good
enough.
My problem is after the car heats up to operating
temperature
I can't get it started until it cools back down. I am
told I need
to get a "high torque" starter. What kind would you
guys
reccomend? How much should that cost? RJ or anyone
else,
if you want more details about the
engine build up you could
write me an email: [EMAIL PROTECTED]
WOULD A HEAT SHIELD HELP TOO!!?
Thanks for whatever you could tell me!
John Warburton
A.C.E.S.
#6448 |
- [Chevelle-list] Built 396 (aluminum heads) hard to start! Chevellebuddy
