I guess I've been incorrect but could someone tell me the difference, if there is any, between 70 front fenderss and 71-72

 

1970 fenders have a flat ridge running along the horizontal inside edge. The 71/72 fenders have 'crumple' ridges

Also the inner liner bolt pattern is slightly different.
1970


1971/72

 

So the exterior appearance is the same? Can The inner fender be made to fit?

 

Yes, the exterior of the fender is identical. The amount the inner fender might need adjusting is very small so it will fit no problem. It's just mm's of difference in lining up the fender to inner liner, and with the inner liner being plastic?? No problem.

The reason for the structural change was safety legislation. The crumple zone fenders absorb and bend with energy impact. The flat ridge fenders would typically be driven straight back into the cowl/windshield area.

For those who are purist restorers of 1970, the correct fender is worth some $$ even if it needs repairing. ALL the metal aftermarket fenders produced are the 1971/72 style. I don't believe the fibreglass repop fenders/clips have or need the crumple feature, since they're mostly used by track cars to reduce weight.

 

Early 71's (maybe only from Framingham?) also have the flat lip. I have two.

 

True enough Frank. There have been discussions on this site about Olds using 1970 production fenders for some time into the 71 production. The first 71 I saw that had its OEM flat fenders? I did a double take because it was different than I'd been used to on 71/72!