70 Rallye hoods - When was the switch to the crumple zones?

[erik70rt]

I was curious as to the general time that '70 rallye hoods (Challenger in my case) switched from the non crumple hoods to the crumple hoods.  I had Challengers with a Feb and March build date and neither had the crumple zones.  My current R/T is a June '70 build and has them.   Perhaps my hood was replaced at some point, but doesn't seem likely given the other sheet metal.  When watching GYC this week, Tony D'Agostino mentioned the cut off for the change was around Dec 1970.  It sparked my curiosity. 

[JS29]

I though he said January 1970, December 1970 would be 71 modal year.

[erik70rt]

I though he said January 1970, December 1970 would be 71 modal year.

Whoops!  You're right. 

[Cuda Cody]

Maybe @TONY  could chime in here and let us know his thoughts.

My experience has been that the change over happened around March / April.  The non-crumple zone hoods use a 5/16" bolt and the crumple zone hoods use a 3/8 (slightly larger) bolt.  They went on to change the hood hinges at least 3 times too.  The 1970 version uses a narrow top bar (the bar that bolts to the hood), then they changed to a wider top bar.  Later on (maybe 72 or 73) they changed again by removing the teeth / gear in the pivot area and went to 2 dual pivot points without teeth.  One thing to keep in mind is that in 1970 there were 2 factories building E-Bodies.  It's very plausible that one factory could have made the switch over to the newer style hoods earlier than the other.   

[anlauto]

Well if you saw it of TV it has to be true

I need a 70 Cuda hood without the crumple zones...

[erik70rt]

Well if you saw it of TV it has to be true

I need a 70 Cuda hood without the crumple zones...

Are you saying TV doesn't tell the truth?  And here I only thought only the internet was unbelievable!   

[6bblgt]

each hood style has its change date as the older style hood inventory was used up (or as old inventory was reintroduced to the line - as is the case with the 'cuda SHAKER hood)

'cuda bulge - April '70
Challenger bulge - June '70

'cuda SHAKER - ?? (lots of non-crush zone hoods show up winter/spring of '71)
Challenger SHAKER - April '70

[erik70rt]

So it's pretty safe to say my June build car had the crumple zones.  Thanks!  Good to know!

[4mayhemi]

Anybody have a chance to post a pic side-by-side of crumple vs. non-crumple for reference?

[erik70rt]

Not a side by side, but here is a pic of my hood with the crumple zones.  If you look at the frame of the hood behind the radiator support seal, you will see two small indentations a coupe of inches apart.  These are the crush zones.  The rear one is right at the hood insulation pad.

[cataclysm80]

Like most things, the hoods are assembled from pieces.
There's the hood shell (the underside) with 3 versions (no crumple zones, with crumple zones, with nose reinforcement and crumple zones on later cars)
There's the hood skin (the topside) with 3 versions (raised sport hood, flat with fratzog hood emblem, flat without fratzog hood emblem on later cars)
There's the shaker bracing (which gets fastened to the shell of a flat hood, and then the skin is cut out of the shaker opening)

The reason for saying this is to point out that throughout the Challenger shaker shortage (from October 69 to April 70), the same shell and skin used to make the shaker hoods was readily available and being used on other hoods. It's the shaker bracing that caused the problem.
Challenger shaker hood bracing is different from 'Cuda shaker hood bracing.


The Challenger hood shell (underside), was used on all the Challenger hoods, and at some date, the hood vendor switched from the No Crumple version to the With Crumple Version, and then at a later date switched to the Nose Reinforcement version.

The factory received whole shipments of hoods from the hood vendor.  The changeover date for each style of hood is different because of how many older style hoods the factory still had on hand when the changeover happened, and also how quickly those hoods were used.
With the flat hood being the most frequently used hood (most number of shipments from the vendor), it's likely that crumple zones showed up there first.
We also see crumple zones pretty early on the Challenger shaker hoods, because the factory had been out of Challenger shakers for months, and it was kind of a big deal for the vendor to supply them ASAP.


Here's an early 70 Challenger flat hood with no crumple zones.  (late August 1969)

[cataclysm80]

They went on to change the hood hinges at least 3 times too.  The 1970 version uses a narrow top bar (the bar that bolts to the hood), then they changed to a wider top bar.  Later on (maybe 72 or 73) they changed again by removing the teeth / gear in the pivot area and went to 2 dual pivot points without teeth. 

This picture might help.

[Jay Bee]

Cuda Rallye hood crumple zones.

[TONY]

hi,

im a little late to the party, so it looks like most if not all questions have been addressed

as per federal regulation, begining in january of 1970 all hood are were supposed to have the crush ribs

while the hoods may have started having the crush rib bracing installed on the hoods by january, they didnt show up on the cars until the assy lines ran out of the non crush rib hoods.  i have an orig paint 70 chall r/t with a spd in febuary and that DOESNT have the crush ribs on the hood, its a hamtrammck car, not sure when the crush rib hoods actually started getting installed, but i would assume later then feb for the r/t hood

id guess the flat hoods with the crush ribs were installed earlier on as there were more cars with those hoods on them, but its just a guess

[cataclysm80]

So it sounds like January is probably when the hood vendor changed to making crumple zone hoods.
It just took awhile for them to show up at the assembly line, based on existing inventory of old hoods, and how many cars were built with each hood style.