jeff@qubix.UUCP (Jeff Buchanan) (04/27/84)
I've been reading with interest the "bench racing" stories about
the ZL-1's and L-88 chevy's of the late sixties. Seems now days a major
engine improvement is measured in terms of MPG and not ET. I too get
sick at my stomach when it seems detroit actually BRAGS about how tiny
engines are now. Oh, but it's OK that they are tiny, cause they've got
TURBOS!!!. Oh my God--- TURBOS!!! That's just great. Now the tiny
engines put out 150 ponies instead of 100. Terrific. Well, I consider
350 cubic inches to be small, 427 is average displacement, and 454, now you're
talking big. The TV ads make it seem like anything with a turbo is hot
cause look at all the exotic race cars that use turbos. They crank out
600,700,800 horses so turbos must automatically mean tons of power, right?
The wimpy turbos Detroit puts on cars bear little resemblance to that
on the Datsuns and Porcshes that race at Sears Point.
I owned a genuine original 1968 L-88 Corvette which I got from
the original owner in 1970. In other words, it was'nt a 435 horse upgraded
to L-88 or a 435 that I dropped an L-88 into, but the real thing, ordered
from the dealer as LPO L-88. It was bone stock except for headers.
Uncapped with slicks (10" M&H) it went 11.09 @ 120.64 MPH with 5.13'S
and a 4-speed. That was at 4000 feet altitude (El Paso, Texas) which
is equal to 10.6 @ 128 at sea level.
It is interesting to me when I read on the NET the stories about
the legendary L-88, ZL-1 in that I'm surprised how accurate they are.
There is no group of people I know of that is more prone to exaggeration
than old street racers and yet the horsepower figures are surprisingly
accurate. To correct some of the inaccuracies of the ZL-1, L-88 tales,
the ratings on both the the ZL-1 & L-88 was 430 (not 465). The engines
wrere identical except the ZL-1 had an aluminum block, L-88 had iron
and the cams were different. The famous "180" cam for the ZL-1 and
"535" for the L-88. The L-88 released in 1969 is the one I'm describing.
The 1968 L-88 had close chambered aluminum heads and the 1969 L-88 had
open chambered aluminum heads like the ZL-1. Chevy introduced iron open
chambered heads a year or so later with square exhaust ports as opposed
to round on the alloy heads.
The actual horsepower produced is questionable. The past couple
of days I've been reading all kinds of figures in the NET. I wonder how
many of these guys who talk about 600 ponies from a ZL-1 witnessed a dyno
test. Now you see what I mean about street racer exaggeration. I've
never witnessed one either, but I talked to an engine builder at Traco
in Southeren California who ran a test on an engine very similar to
the one in my 1968. He claimed 530 ponies. His 1966 Corvette turned
a slightly slower trap speed than my 1968, but he was running 3.36 gears.
Since gearing only affects ET and not trap speed too much, I'd say
my motor was putting out at least that much power. So I'd say 530-540
HP is typical of the power these engines cranked out.
The factory rated compression ratio of these motors was 12-1.
What a joke! Typical was 10.5 to 11.0 to 1. See, 12-1 is what you get
with a 116.9 cc head and that's what the factory bases their advertised
CR on. Problem is, the heads don't have 116.9 cc's. They really have
about 122 cc's. I've cc'ed more heads than I care to think about the
range I've seen is 119.8-123.6. That yields a CR of 10.5 to 11.0 with
a .040 gasket and piston .005 above the block.
--
Jeff Buchanan @ QUBIX Graphic Systems, Inc., Saratoga, CA.
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decwrl!qubix!jeff@Berkeley.ARPAjeff@qubix.UUCP (Jeff Buchanan) (04/27/84)
Also, I read with interest the comments about how the big block
Chevys ruled the street. I've done much street racing in Washington D.C.,
Austin & El Paso Texas, and talked to friends who have in Southern Cali-
fornia. To say that RAT powered 'Vettes, Camaros, and Chevells were
competitive against the likes of 440 six packs, hemi 'Cudas, and 428
Cobra jets in Mustangs is a gross understatement. Typically the 10'th
fastest Rat in a given neighborhood might have a close run with the
fastest hemi or 428 Ford.
--
Jeff Buchanan @ QUBIX Graphic Systems, Inc., Saratoga, CA.
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