Words and photos by Jeff Burk
Troy Coughlin likes--no make
that loves-- really fast doorslammer racing. That’s
proven by the fact that in his career he has driven and won
in Pro Stock, Pro Modified, Stock, Super Stock and a variety
of bracket cars. That love of fast door cars had a lot to
do with his decision to go NHRA Pro Modified racing this season.
But evidently Coughlin just isn’t getting enough seat
time just by driving a supercharged Pro Mod for the Mike Ashley
team, ‘cause he’s just put the finishing touches
on Pro Street Cavalier that he is going to race in the NMCA/Edelbrock
series basically allows almost any engine/induction combination
without a lot of restriction so Troy decided to use a fairly
unique “Chevy” powerplant for his Pro Stock style
Cavalier. He decided to have mountain motor maven Sonny Leonard
build him one of the 815 cubic inch, five-inch bore center
engines using Sonny’s “semi-hemi” Chevy
Those engines normally come fitted with split dominators
but Troy Coughlin wanted something different so he got in
touch with EFI whiz John Meaney and had him put a system together
to replace the carburetors on the 815 inch Chevy.
DRO went to Sonny's Lynchburg, Virginia, engine factory for
the first dyno test at the biggest EFI racing engine we've
ever heard of. When we got there the engine was already on
the dyno getting a few last-second tweaks from Sonny himself
and shop foreman Tom Kidd while they were waiting for EFI
guru John Meaney and Coughlin’s crew chief Bryan Metzenhiem
to arrive so that Meaney could tweak his "Big Stuff"
EFI system while the engine was being dyno-tested. They also
wanted to try a couple of different throttle body systems.
On the dyno one of Sonny's 815 ci Pro Stock-style "Hemi"
Chevy with two split-Dominators (four two-barrels) for induction
makes 1785 hp at 7600 rpm and 1305 foot pounds of torque at
6600 rpm burning Torco 118 NOS gasoline -- you need the highest
octane fuel you can get when the engine has about 16.5-1 static
Troy Coughlin’s 815 cu in EFI motor used two different
styles of fuel injection throttle bodies for the dyno testing
, but they kept all other engine and tuning speeds the same
as when the engine had carbs.The best numbers for the EFI
motor seen over about a 20 pull dyno session was 1765hp at
7600 rpm and 1300 foot pounds of torque at 6600 rpm, about
20 less horsepower and five foot pounds of torque less than
a carbureted engine.