[Outwest34au]

Dodgy (also spelt dodgey) is a aussie term.

Australian term.
1. Something or someone that is a bit suspicious, doesn't seem quite right. Doesn't seem the real deal.
2. Slack, broken, worthless or useless.
3. Not very appealing.
1. That car salesman seemed a bit dodgey.
2. This old car is pretty dodgey.
3. That band last night were pretty dodgey.

It isnt a personal insult and it isn't a reference to Mopar but maybe Dodge wasn't popular here and that's where the term originated? I'll have to try and find out now, I'm curious if it is derived from a car reference.

1/4 inch is pretty solid, unless you're trying to impress a girl. Will you tap threads and bolt the body to the chassis?

Re the backfiring, do you have vacuum advance? Have you tried it connected and disconnected?
Have you measured manifold vacuum at idle? That may tell us a story.
I am not a weber expert, not even slightly so will leave that to the pro's here.