1969 Race Dart w/ 426 Hemi- garaged for 45+ years

I’ve been a similar situation although MUCH smaller scale. Where I had a guy build an engine with mostly my supplied parts. I didn’t ask him his rate, how much he thought it would cost or anything like time ect. I knew I could trust him and this was at the top of my list. Like they say priceless.
Well, 6-8 months later plus or minus, I didn’t keep track, the engine was ready to be picked up and already dynoed with paperwork.
When he sent me the bill( he is out of state 12hrs drive ) I couldn’t believe how little he charged me.
The check I sent him was several hundred more than required because I was grateful for his honesty and integrity.
Long story short, maybe the op will have an opportunity to pay fair market value. Maybe payments over time as funds are available? I don’t know.
You both seem to be great people and I hope it works out for both.