1974 Big Block aficionados...please step inside!

[KWB]

Have a friend that purchased '74 4-speed 454 big block Coupe (yellow) he is trying to document. He says that he has the original factory build sheet, but is unsure what gears are in the rear end or what the RPO codes stand for. It also has a couple of items on it that I am not sure are factory (i.e. side pipes and an alarm under the fenderwell that uses the factory ignition key to arm). The valve covers have "MT with the chevy bowtie" on it, which sounds like they may have been replaced and possibly a new cam installed.
Any words of wisdom and what to look for would be much appreciated...many thanks!

 

[6880 Mike]

Have a friend that purchased '74 4-speed 454 big block Coupe (yellow) he is trying to document. He says that he has the original factory build sheet, but is unsure what gears are in the rear end or what the RPO codes stand for.

Factory rear ratios will be listed on the build sheet, possibly referenced G80 or G81 or something similar.

...it also has a couple of items on it that I am not sure are factory (i.e. side pipes and an alarm under the fenderwell that uses the factory ignition key to arm)...

Side pipes are not stock. Theft alarm is stock if it's in the left fender.

...The valve covers have "MT with the chevy bowtie" on it, which sounds like they may have been replaced...

Correct; the valve covers are aftermarket.

 

[KWB]

Factory rear ratios will be listed on the build sheet, possibly referenced G80 or G81 or something similar.



Side pipes are not stock. Theft alarm is stock if it's in the left fender.



Correct; the valve covers are aftermarket.

Thanks for the quick reply...I'll try to get some more information from him today. What ratios did they usually put in the 4-speed manuals with the 454?

 

[JohnZ]

Thanks for the quick reply...I'll try to get some more information from him today. What ratios did they usually put in the 4-speed manuals with the 454?

With the standard wide-ratio (M20), 3.08 was standard, 3.36 optional.

With the optional close-ratio (M21), 3.36 was standard, 3.08 or 3.55 optional.