Motion cars were heavily modified and tuned for racing so no doubt they would have been the fastest back then.

 

In 1976 I rode in a Motion 69 Z/28, crazy fast car, same guy had a 69 Chevelle SS L78 that was really fast but the Z had more top speed

 

A Yenko and COPO Chevelle would be the same,a L72 427, 425 HP
Super Stock magazine tested a 69 Yenko Chevelle, best ET 13.31@108 MPH:

Yenko Chevelle Drag Test - York US 30 Dragway - The Supercar Registry

Yenko Chevelle Drag Test - York US 30 Dragway Yenko Chevrolet

www.yenko.net

Baldwin-Motion car would typically be a 427/L88 type build, guaranteed to run 11.50@120 MPH
Best time for an LS6 back in the day was 13.12@107, I believe Hot Rod or Car Craft magazine.

 

Those L88s were beasts.

 

In high school I had a 68 Z/28 with a L72, there was a LS6 Chevelle in the same town, ran the best of 12.40 with headers and slicks @ 2200 feet elevation, it wasn't beating my Camaro.

 

LS6 is production fast.......not so much on cars with mods and tunes.

 

Bone stock I think the L-72 would come out on top. On any given day it's a toss-up.

 

1969 Yenko Camaro, all stock L72 except for open Heddman headers and 8" slicks, M21,4.10 gear:
11.94@114.5 MPH back in 1969

Yenko Camaro Drag Test- York US - The Supercar Registry

Yenko Camaro Drag Test- York US Yenko Chevrolet

www.yenko.net

 

First off, I never tracked my '67 L78 Chevelle (mainly due to timing, college and Vietnam...just life!), but that car was not "heavy" compared to later model Chevelles, and with the Mickey Thompson Super Scavenger Headers and slicks (which were street legal in the late 60's) made that 4-speed 4.10 Posi setup REAL QUICK! I always knew my car had way more horsepower than 375HP, but it has since been proven that an original L78 with headers (just plain old headers, not M/T SS Headers) put out about 459HP!

I only drag raced my buddy on his Kawasaki bikes, which were fast, beating one handily (the 750 not so much), so I always guestimated that the way my car was set-up it could get into the 11's in the 1/4 mile. I still believe that to be very realistic.

Was it as fast as a Yenko or Baldwin Motion car?.....sure would be fun comparing!

 

The 65 396/425 was more like it! I think that's why the 66 L-72 was rated at 450 hp early in the year,the Corvette had to be the top dog in the line-up.

 

Not true that all Motion cars were heavily modified. The base Motion cars came with a stock 427/425 but all of these cars were dyno tuned. I don’t know if headers were part of the package, if they did a stock LS6 wouldn’t have a chance. The Phase III cars were the ones everyone thinks of that had the 11.50 guarantee.

 

X-2 the "base" B/M car got a dyno-tuned L-72 stocker

 

Back in 1970 my good friend had a 425/409 Biscayne car and he could smoke an LS 6 Chevelle's (bone stock) and raced a few of them. He ran one guy and put 3 cars on his 454 that night, 3 weeks later the guy showed up with the car and asked to race the Biscayne again. Off they went but the outcome was mighty different when the LS-6 car we found now had headers and free flowing exhaust on it. He got the 409 car by and easy 3 cars that night as he hooked up pretty well. Sure was fun watching all the muscle cars race in those days.

I have a buddy that has a home built L-88 427 and it's fast, but his Nova with the 523 Musi engine just smokes that L-88.

 

Sir it is pretty simple. For as purchaes off showroom floor it would go

MOTION
Tuner like yenko
1969 COPO
1970 LS6
L78

After that, it would be down to tuned or preperation. A tuned and prepped L78 would beat an normal LS6 is not set up properly like valve adjustments, csrb and distributor tuning.
A good shop set up in tge cars listed would play out in that order.ĺ

RH

 

I test drove a LS-6 in 1971. It still had the dealer installed header box in the trunk. Wanted it but my Dad and Uncle Sam had other thoughts.
Rick