2 come to mind...

I took my 79 cutlass off road and knocked a hole in the oil pan. I had just spent 2 weeks putting a 1970 high compression 350 Rocket V8 in it and didnt want to change the pan. I bought a fiberglass gas tank repair kit to patch it. It lasted the next 80,000 miles until I put a 403 V8 under the hood.

I was using a rusty 82 dodge maxivan to get stock for my business in Chicago. On my way back to wisconsin my roof let loose in the back and started flapping. It was only still attached in the front. One of the items I had bought was a case of mixed color duct tape. I used 5 rolls to tape the roof down. Orange on the left, blue on the right and red on the back. I drove it for 2 years before I sold it for $200. The guy didnt believe me that you needed to add a quart of oil every week and he got less than a month out of it, but the tape held.

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1959 Gravely LI, 1963 Gravely L8, 1973 Gravely C12
1982 380SL
1978 450 SEL 6.9 euro restoration at 63% and climbing
1987 300 D
2005 CDI European Delivery
2006 CDI Handed down to daughter
2007 GL CDI. Wifes