backlash and very quiet operation. It was
designed that way to keep the heads,
and the engine, as narrow as possible.
Without this design feature, on a nar-
row head, the twin cam drive pulleys
would be considerably smaller so as not
to touch each other. That would, in turn,
lead to higher belt loads because of the
reduced driving radius.
And when it comes to spinning those
cams, the SB4 sings like few other
engines. From 2,500 to 6,000 rpm, the
power ramps up on a 45-degree angle,
crossing the 400-horsepower mark by
4,300 rpm and 500 horsepower by 5,100
rpm. After 6,000 rpm, the power curve
bubbles up and races to 700 horsepower
by 6,500 rpm and finally tops out at 750
horses at a stellar 8,000 rpm.
It would be natural, too, to assume
all that high-rev horsepower comes at
the expense of torque. It’s true that the
engine isn’t a big-block torque monster,
but it tops out at around 570 lb-ft at
6,000 rpm, so it’s no slouch in the grunt
department.
As for Roadster Shop’s involvement,
the company partnered with Mercury
Racing to bring the engine from the pro-
duction line to the market.
“We have made it our business to pro-
vide customers with the latest in design,
chassis and performance, all packaged
to save time and money, while helping
ensure trouble-free enjoyment,” says
Gerber. “The SB4 7.0 offers a unique
opportunity for us to deliver one of the
industry’s most unique engines in a
turnkey package. We’ve already used it
in several of our vehicle builds and the
results have been spectacular.”
So, will it fit? Probably. With those
DOHC heads, the SB4 7.0 is wide, no
doubt about it. It stretches right around
30.3 inches (769 mm) at the front, mea-
sured across the broad timing cover,
and 29 inches at the rear, from head to
head. That’s roughly 6 inches wider than
a conventional LS engine and about 10
inches wider than an old-school small-
block Chevy, but only about 2 inches
wider than a conventional big-block.
Most of the extra width is hanging out
over the headers, which will likely pres-
ent some master cylinder interference
issues on most generations of Corvettes,
but resourceful builders should be able
to work around it. Like a conventional LS
engine, it’s also a lot lighter than a big-block,
by 150-200 pounds.
And the other big question: What does
it cost? The base price is $32,995, from
Roadster Shop. That includes the control-
ler, but not the front-end accessory drive
system. That adds another $2,495 to the
bottom line.Value is always in the eye of the
beholder, but the prospect of 750 natu-
rally aspirated horsepower with DOHC
and an exhaust note that will send a
shiver up your spine are elements that
are difficult to quantify. And the familial
link between it and that other DOHC V-8
Mercury built all those years ago is also an
intangible and enticing factor.Corvettes are all we do.CALL OR ORDER ONLINE
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