Setting up an engine after rebuild, ignition timing, compression testing, etc

[420sx]

Looking for a little advice on this here dag'gum volvo. haha

I recently rebuilt the motor, first motor ive rebuilt myself. Ive got about 400 miles on her since first startup, oil changed like 50 miles ago. The motor runs very strong- I have no confidence issues with the bottom end. The issue im having is making it run perfect.. i cant seem to get it dialed in. It runs like crap when its cold, and will stall if i try to drive it before its warm. The spark plugs are white, it appears to be pretty lean. I had a coworker of mine have a look at it, and he said its "late and lean," meaning I needed to adjust the ignition timing to account for the head being milled. Once the car revs up, it runs good, but it idles rough and doesnt make as much power as it should.

I loosened the dizzy bolt and tried adjusting the dizzy side to side. When I turned it all the way clockwise (advanced I assume), the car ran better, but the problem was definitely not solved. I currently have it adjusted all the way over.

My next step is going to be to check for vacuum leaks. I can do this by spraying the intake manifold with carb cleaner while the engine is running, right? If the rpms change, ill know Ive got a vac leak.

At idle, the car pulls about 10-12psi of vacuum. I was told to set the timing so the car idles with just under 20psi of vac, but the timing didnt really affect anything when I moved it back and forth. Im really hoping im not off a tooth on the timing belt. I marked the belt on the crank pulley and cam gear when I pulled it apart, and everything went back together the same way.. so Im a little confuzzled. Any advice would be appreciated.

Also, I was at first suspecting a blown head gasket after noticing some seeping on the side of the block. Im starting to think otherwise. Initial compresion test after the rebuild was 120-130-130-150, which kind of followed the cylinder sizing of B-C-C-D. After another 300 miles test results came back at 135-150-150-160. Not sure if i should be worried about that front cylinder or not, but im not stressing over it just yet. Im gonna let the rings keep seating before I worry about it, although given that all of the numbers increased by the same amount roughly, I may be looking at a valve issue.

Im not really sure what Im asking here, Im just trying to provide as much information as I can on the matter. Any advice would be appreciated.

[ThePrimerSuspect]

Is it a pushrod or OHC motor? Does the distributor have a gear or is it just slotted? If its gear driven its probably off a tooth.

[itwillboost]

You set all the timing marks correct to factory specs right ? Sometimes people don't line up the links correctly, and only line up the cams, pistons, and crank. Your right about the carb cleaner but sometimes that doesn't work. I would run one or two vac tests.

[underpressure02]

I just skimmed your post but you said you had the head milled? Did you degree the cams in or just throw the head on and line up the timing marks on the cam gear(s) and call it a day?

Also did you do a leak down test? That will tell you a lot more then a compression test.

[420sx]

Cams were never removed from the head. Motor was rebuilt due to a blown head gasket and bad rings, so the head was taken down to provide a flat mating surface. Timing marks were lined up with factory, but thats the part of the rebuild that Im the least confident about. But the marks I made on the cam gear, crank pulley, and belt all lined up when I put the head back on.

Its an OHC motor with a gear driven distributor.