I'm also involved in classic cars, and I have a funnel that you can bend, twist, mold around just about anything. I use it to drain the oil in my 67 GTO because the oil pan has the drain pug on the right side. It normally made a real mess dripping all over everything. A friend gave me this neat funnel. It's like a hard silly putty, and mine is green. I believe I've seen a couple of companies that advertise a few sizes in my car magazines. I don't know the name or brand, but could try finding out. I'm not sure, but I would think it would work better then foil and tape. It stays put and is will even drain around corners. Cleans up real easy and deals with any fluids other then acid. Mike