Exhaust Backpressure- 3" vs. 2 1/2"

[Hog]

Originally Posted by Bob Eyres

Yes, they were delivered with that exhaust system. But the race cars Zora intended them for almost invariably used tube headers, and "off the road" side pipe configuration seen on factory supported L-88's.
I doubt if any part of those systems measured 2 1/2", except maybe the header downtubes.

A side issue- Where did they get that 430hp. figure? It's generally thought that it was pulled out of the air and put in the order form to coax the buyer into ordering the 3 carb 435hp. street version instead of the L88 race motor.
But did they "rate it" by going down the dyno rpm scale until they found the number 430, and rate it at that rpm, instead of where it actually peaked?

That's exactly what they did,
L88 number 21550 made exactly 437hp@5200rpm and 560hp@6400rpm on 115 octane fuel running tube headers.

We have to remember that a vast majority of the populous had never heard of a ZL1.
There were only 20 1967 L88s sold. L88 cars also had a laundry list of L88 only(and the following L88 delete) options that helped destine them for race use only.
In Chevrolet sales brochures, in 1969 the engine was listed as a Special High Performance Engine (Off road Application Only Only)

In order to order the L-88, mandatory optional equipment included:
L-88 engine $947.90
J50 vacuum bower booster $42.50
J56 heavy duty 4 wheel disc brakes $42.15$342.30
M22 (rockcrusher 4 speed manual trans $237.00
K66 transistorized ignition $73.75
F41 suspension $36.90
G81 Positraction rear axle $42.15
C48 heater/ defrost delete package credit of $97.85

L88 delete
Further efforts by Chevrolet to ensure its use as a race car, as well as being lighter the following were not available once the L-88 box is checked:
-radio
-power windows
-air conditions
-power steering