add
add
Menu

Chevy Big Block series- the 427 variations

Capture Capture4

The Chaparral and McLaren M8B raced using the 1969 ZL1 Mark IV version of the 427 with impressive results. Specifications and mechanics of the L88 production model of the engine are virtually identical to the ZL1 although the block and heads are cast from aluminum rather than iron dropping the weight by 110 lbs-now with a dry weight of 575 lbs. (261 Kg). Other peripheral pieces such as the water pump and the special race tuned intake manifold is also of cast aluminum contributing to the lower weigh scale reading which is now in the same ball park as the Chevy small block cast iron power plants. The combustion chamber in the ZL1 extends into the cylinder heads, it sports a racier camshaft, no shroud on the radiator, and the idle is very ropy. This racing engine will only run on fuel with a high octane rating of 103 or greater making the race engine unsuitable for road use. The highest octane fuel commonly available at any public service station is octane 102 RON fuel (Sunco 260).

Capture3

The ZL1 engine produced results that turned this power plant into a legend and subsequent dyno tests rate the engine at 376 SAE net horse power with surges at higher rpm of up to 524 gross hp. The particular engine tested optimal carburetor tuning, perfect ignition timing, open long tube racing headers, no air cleaner, and no power reducing accessories. There was another dyno test done on a different ZL1 engine this time in a COPO Camaro. This engine had been newly rebuilt and partially blueprinted but produced similar results with almost identical figures. The ZL1 427 engine was never produced in large quantities so very few units were available for testing ’69 and ’70. A well-tuned ZL1 engine in a stock car the engine not uncommonly turns in recorded times of 13.1 seconds for the quarter mile and reaching 110 mph which supports the 376 Net hp figure. Super Stock and Drag Racing Magazine recorded a professionally tuned ZL1 Camaro driver by drag race legend, Dick Harrell, doing the quarter mile in 11.62 seconds and achieve a speed of 122.15 mph. This Camaro is also equipped with S&S equal length headers, drag slicks, and has a few minor suspension revisions as well. Patrick Hale developed an accepted power/speed formula that suggests the speed trap time and the speed of 122.15 mph could have been reduced with larger racing slicks. The quarter mile results also suggest that the entire  exhaust system from the manifold to the pipes was restricting the power in the production version of the L88 and the ZL1 engines. Extraordinary performance has a cost and the 427 with the ZL1 option for your 1969 Corvette was $4,718.00 which doubled the sticker price of a new Corvette in 1969. There were only 69 Camaro models with the COPO 9560 option roll off the assembly line. There were also 2 Corvette units with this factory ordered, but dealer installed, option produced in 1969.

CaptureCapture2

Chevrolet turned the adaptability of the Mark IV big block components into a cash cow. They kept their parts retailers bins full of assorted high performance parts including complete replacement engines in crates; ready to drop into any appropriate model Chevrolet. Most of these items were originally meant for the Can-Am competition racing not for “over the counter” retail. They were marketed as heavy duty which is possibly an acceptable term for the equipment but actually most of these parts only increase the engines dependability at high rpm. The top power option 427 engines beginning in 1969 are equipped with a new style open “open chamber” cylinder head, up graded crankshaft, improved piston, and connecting rods which are all a result of the Can-Am racing program.


One thought on “Chevy Big Block series- the 427 variations”


  1. Kirk Boand says:

    The best racer I had was a 1970 Mustang Boss 302 with an e.t. of 11.03 in the 1/4 mile. Pure stock hard runner that dyno’d at 525 H.P.


Leave a Reply

Your email address will not be published. Required fields are marked *


Most Recent Facebook Posts


Comments Box SVG iconsUsed for the like, share, comment, and reaction icons

4 hours ago

Muscle Car Fan

More 50 and 60’s Car parts stored inside for sale ...

1 day ago

Muscle Car Fan

Barn find 68 cutlass 455, a barn full of 50s and 60s Oldsmobile and Cadillac parts. Video tour one Cutlass at the end still buried ...

Comment on Facebook

What's the price on the 68 olds

View more comments

2 days ago

Muscle Car Fan

Anyone know what this bumper guard fits? ...

Anyone know what this bumper guard fits?Image attachmentImage attachment

Comment on Facebook

Still have not tracked down the car it goes to

Close No cut out on these for the bumper like this one has

Most of the fords had a flat rubber strip?? I’m thinking mopar , satellite or cuda class

First thought, but naw...

71 Plymouth satellite.

A early 70s model. Maybe a ford maverick or a Plymouth duster? Hard to tell

Ford Pinto maybe. Though those old Challengers had similar guards like that.

On the car, am sure of it.

Who cares , ruler is a keeper though . Vote RED across the board .

Looks like it's for an early squarebody gm truck

a car

Ford 250 pickup push guard

Keep it chunk the ruler!! Blue all ready!!

Could be a vw bug 60s 70s

70s VW Beetle??

No markings on it anywhere?

How about a Dodge Dart?

1978 Ford LTD

I got it a car right

Camero split bumper

Can we not do car stuff w/o the political stuff?

Square body's had those too

A bumper

A bumper

View more comments

3 days ago

Muscle Car Fan

Barn Find Backhoe extracts 1967 Cutlass 442? 35 years resting ...

Comment on Facebook

I have a 38 chevy sedan, ready to restore.

This great car must be restored.

Beautiful cars!

I would like to see the car after it's been restored

Awesome car

In its DAY WOW !!

Looks like the 330 ci motor as well and not the 400.

Supreme with factory Spanish red paint.

I would already be pressure washing it

I just don’t understand people like this. WHY DIDNT THEY COVER IT UP!!!! Good grief!!!

Sweet

They got it running and driving

VIN and Title check in order Something smells fishy

Is it for sale

Dirty sweet !

View more comments

6 days ago

Muscle Car Fan

1952 olds super 88 convertible awesome car ...

Comment on Facebook

They were the first muscle cars started in 1949 for olds they were fast.

Nice car.pretty

Nice ride

I love that ‘88!

View more comments

Load more