'72 LS-5 454 Engine

[windrider50]

Does anyone know for sure if this engine can use unleaded as is, or does it need the harded valve seats installed in the heads?

 

[wallyknoch]

It really will not hurt anything.

 

[cruzer99]

72 was a 8 1/2 : 1 compression so you can run reg unleaded if you want not that I would. This also says you could put a blower on it also.
Just a thought........

 

[MaineShark]

I think it was '70 that was the last leaded-fuel year. If not, it was '71. By '72, they were definitely running on no-lead.

Joe

 

[Vettehead Mikey]

It was built for UNLEADED fuel at the factory, as others have stated. Whether it can run on REGULAR (octane) fuel or not is another matter.

 

[Tom73]

All depends upon how you drive the car. If you drive it within reason you should be okay. But if you are a big time hot rodder and get the valves and valve seats extremely hot then you could have problems.

Unleaded was not required until the 75 model year when the cars were equipped with cat converters. To get ready for unleaded, GM dropped the compression in '71. Then in '73 they added the hardened valve seats that would not need the lead for lubrication/protection of the seats.

Your '72 probably has not had lead in it in 20 years. You should be okay. But if it makes you feel better you can always add the lead additive.

tom...