Car Craft – November 2019

This is not meant to discourage you from
putting effort into properly tuning your
carb, but after spending many hours
working with the carbureted setup on
the 632 big-block, Senior swapped out
the carb for a Holley Sniper Stealth 4500
EFI system. Within 30 minutes of the
first fire-up with the EFI on the engine,
the self-learning software had the fuel
curve pegged and we were making
power pulls. The peak power numbers
were similar, but working with the Sniper
EFI was simply tons easier.

➔SOURCES
Holley; 866/464-6553; Holley.com
Prestige Motorsports;
704/782-7170; PrestigeMoto.com

impressive of all, Senior had it up
and running on the dyno within
30 minutes.
On the dyno, the carburetor pro-
duced peak numbers of 824.9 lb-ft
of torque at 4,500 rpm and 782.0
hp at 5,400 rpm. (Remember, this
engine is built for torque across an
rpm range that, in real life, will end
at 5,200 rpm—not maximum
horsepower.) Within an hour of
cranking up the big-block with the
Sniper EFI, it was pumping out
slightly better peak numbers
(827.3 and 787.1, respectively)
with a rock-solid fuel curve.
The point here isn’t differences
in peak power and torque, how-
ever. After all, a properly sized and
well-tuned carburetor should usu-
ally be able to keep up with an EFI
system at producing peak power
numbers. The shocking difference
here is how easy it was to run this
engine on EFI. Senior, who has
decades of experience tuning
carbs in stock-car racing, spent
days on the dyno tuning the Ultra
Dominator Holley to meet his
exacting standards, and that’s one
of the most easily tunable carbs
on the market right now. On the
other hand, after less than an
hour, the self-learning computer
on the Sniper EFI had the fuel
curve dialed. And, unlike the carb,
it will continue to adjust in the
future as other variables such as
weather and altitude change.
So the lesson here? Don’t give
up on the venerable carburetor,
especially if that’s what you’ve
already got. You can tune it to fit
your specific needs. But if you
want to make your life easy, mod-
ern EFI systems are more afford-
able and capable than ever before
and are definitely worth a look.

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