why the m21s

Eddie M. · #1 01-30-2006, 07:24 AM

got a question i been wanting to ask since i got my ZL1 back in 76, why were the m21s used instead of the m22s in most of the ZL1s? even seems like most hp cars that i see and read about have m21s,is it a cost factor or HP or?
Eddie

Eddie M. · #2 01-31-2006, 06:06 AM

well i guess nobody else knows either

**Mr70** · #3 01-31-2006, 06:09 AM

I would think it was about the cost.
The ZL-1 option being the most expensive option,the ordery would try to cut costs elsewhere,and the M-20 wasn't gonna do it,but the M-21 would handle it.

camarojoe · #4 01-31-2006, 06:11 AM

I have heard that it was believed the M21 was just as rugged as the M22 when the cars were ordered, and the extra cost of the M22 couldn't be justified. All the 4 speed Yenko cars were M21's too.

**mockingbird812** · #5 01-31-2006, 06:12 AM

O.K. I'll bite off and give someone a target. My guess is it was a learning process. In '70 the 454 motors (LS5 and 6) had a mandatory mating with the rockcrusher. Probably took them awhile to see that the 20 and 21 were not up to the task hooked up to all of that torque. Probably saw more and more warranty replacements/reworks and got smart in 1970.

**Mr70** · #6 01-31-2006, 06:24 AM

The only problem I have with that Sam is the LS-5 part.
For 1970,360 Hydraulic Horse Power couldn't get an M-21,yet the 375HP Solid Lifter could,and yet not get the M-22?

Unless like you said,it was a Torque issue.
415 @3600RPM for the 1970 L-78 compared to 500 @3200RPM for the NEW LS-5 & 500 @3600 RPM for the NEW LS-6...

Eddie M. · #7 01-31-2006, 06:30 AM

i wonder what the cost diff would be? seems like after spending 4,000 for an option another couple hundred would not mean much but then back then a couple hundred meant more then today i guess
Thanks for answers
Eddie

camarojoe · #8 01-31-2006, 06:34 AM

If you recall, at the time of ordering, it wasn't known that the option was going to cost so much. I know that Yenko wanted to keep the option costs to a minimum and still have sellable cars. The ZL-1s were about as bare-bones as you could get, so Fred Gibb wasn't ordering many other extra-cost options on those either.

Eddie M. · #9 01-31-2006, 06:53 AM

thats true joe if they would have know that there would not have been any ZL1s ordered
Eddie

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