I haven't made that mistake, but I'll share a fun one. When I built my first "hotrod" flathead, I was 15 years old - 4 1/8" stroke 3 5/16 bore, 284 cubes, Weber F6 cam, Navarro heads, Edelbrock 3x2's intake . . . lots of good stuff.
I acquired a Harman-Collins Dual-Coil distributor (looks like a crab, with a few extra pieces). Anyway, got the engine all together and was going to start it on the engine stand (just couldn't wait to complete the rest of the car! - had to see it run!).
Now imagine, you're 15, you've been working on this engine with the help/mentoring of Joe Reath (and others) . . . it is ALL you've thought about and slaved over for a couple years. You have a lot of your own hard earned money in it - too many hours to count as far as time . . . and you built and assembled it yourself (with some great assistance along the way - thanks Joe!). AND - you've never built a flathead before.
Back to the Distributor: I had Joe Hunt (another great mentor) run-up the distributor for me - he checked it all out, put new points in it, checked the advance out, etc.. Heck, I had help from a lot of experts, but I'm still nervous as Hell, but excited as all get out . . .
So my wonderful Mom is in the garage to participate in the BIG MOMENT. She's always been my "HotRod Buddy" - even went to Bonneville in 2013 with the FlatCad crew (flew out to Salt Lake all by herself, rented a car and met us on the salt - at 81 years young!).
Time to Fire Her Up: I pump the accelerator pumps on the three 97's a few times, then hit the starter button I'd rigged up (to a Mustang solenoid). Crank, crank, couple coughs, couple spits out the zoomies. More fuel, crank it some more . . . crank, crank, BLAM! - huge backfire - flames out all three carbs. The backfire was big enough to create a huge amount of crankcase pressure . . . blew that nicely chromed dip-stick right out of the pan and hit Mom in the chest! You should have seen her eyes - like saucers . . . and I'm sure mine were as well.
Well, something was OBVIOUSLY wrong with my ignition system - was firing at the wrong times. Hell, the distributor has an indexed slot/tang - it only goes in in one way (unless you try hard to get it 180 degrees out.
). I knew I had that right . . . so what was it ???
Firing Order - Dual Coils - Firing Order - Hmmmm: Well, I sat there and I looked at that distributor and knowing that it was a custom rework for dual coils, dual points, 4 lobe cam, etc - there was something I didn't know - what was it? The rotor had TWO contact tips on it - one for each coil. Ah Hah! The firing order had to be different than what was on the stock Ford cap - as it fired back-n-forth across the rotor (switching sides each time). So I traced it out and put stickers on the cap for the four cylinders that were off, put the plug wires in the now "custom/correct" position and off she fires. Mom and I are now laughing hysterically over our prior "dip stick" incident! (PS: Saved that dip stick all these years - put it in my 32 Cabriolet and sent Mom a picture - asked her if she remembered our little 'incident' 40 years prior . . . she did!). It ran like a beast . . . we were both relieved to say the least.
Custom Distributor Cap: I didn't know there was such a thing as a custom "Harman-Collins" crab cap - where they used hot steel lettering punches to melt in the new firing order . . . didn't see one until years later.
Experiences, Fun Times and Good Memories: So yes, maybe one of the added benefits of these old cars is that because of our work on them, our blunders, our falling down and getting backup up, the problems we resolve, the "helpers" we rely on - we actually learn a lot of things (and we make a lot of friends along the way).
Experiences that last a lifetime . . . with others who enjoy our madness.
THANKS MOM!