63 to 64 Chrysler factory Super Stock question

[Ghoste]

My understanding has long been that the front end on the lightweight cars was changed from aluminum in 63 to thin gauge steel in 64 because of NHRA mandate.  Lately I read an article alleging the change was made by Chrysler for "durability" purposes.  I can't understand the partially added durability of thin gauge steel over aluminum being much of a concern on a special purpose car intended for a single season of racing.  But on the other hand I've never seen a copy of any document from NHRA ruling that alloy front ends were banned.
Are there any drag historians here that know better? 

[gtx6970]

Dont hold me to this as I am a long way from being well versed on 63-64 cars.

But I think there was aluminum ft ends on the 64 cars as well.

Again I am not 100% but I dont think the light weight steel cars arrived till 65 

If I am wrong I'm sure someone will correct me

[Ghoste]

You could be right on that as well.  Do you have any idea about it being a Chrysler decision or a rule change though?  John Kunkel knows these cars I think?

[JB400]

I thought the switch back to steel was in '65, while both '63/4 had aluminum?

[el dub]

Did they have aluminium doors like this race car?

[gtx6970]

I am not aware of them having aluminum doors

[John_Kunkel]

I thought the switch back to steel was in '65, while both '63/4 had aluminum?

Yep, '64 was still aluminum. Acid-dipped steel was '65 A990 cars.

[Ghoste]

John, do you know if it was a Chrysler decision or a rule change?

[John_Kunkel]

The 1965 NHRA Super Stock rules required all-steel bodies but they didn't specify how thick.