Engine trouble 292

[NeverDone50]

So I have a 292 swapped into my '50 and I'm having some issues. When starting up, it spits back/coughs through the carb (rochester 1bbl). So i've rebuilt the carb, it's been timed 4 degrees BTC, new pertronox kit, new spark plugs, etc. Anyway, I can get it started, but I it wont run unless I set the idle around 1000 rpm. If I try to tune the idle lower, it coughs randomly and dies. So I did a compression check and all the cylinders were reading about 125-130psi except cylinder 1, which was reading 90 psi. I poured some oil in the cylinder and rechecked the compression and it didn't change. I'm assuming its a leaky intake valve. I'm not a mechanic and I'm learning as I go so what are my options on fixing this issue?