1982 G20 Engine Swap

I have a 1982 G20 Waldoch Conversion van I converted into a work van. On my way home from a job I blew the head gasket in the original 305. The 305 was pretty much worn out and I got a built 350 from a friend for dirt cheap. Got them swapped, and had the 350 running, but it backfired like crazy and idled between 1200 and 1500 rpm. Advanced the timing so it stopped backfiring but then wouldn't start. Was told by a friend that has done quite a few swaps to put the distributor from the 305 on because it has ESC. Swapped distributors, now no spark at all. Possibly a bad module in the distributor? Another problem I have is that the power steering pulley is slightly out of alignment with the crank pulley and water pump pulley. Do they make shims for the power steering pulley or is there another way to get them lined up?

Any help would be greatly appreciated.

Travis

I believe your back firing is a timing issue...and I know you don't want to hear this but I think your timing marks on your chain and gears are not in the correct position...now I could be wrong and your issue may be caused by incorrect rocker arm adjustment, but I doubt it....remove the timi8ng chain cover...if for nothing else...your own piece of mind...ensure it is correct..bring number one piston to TDC and set your distributor...after you put it back together leave your distributor a little loose this way you can make small adjustments to the timing as far as your power steering pulley ..I've done this swap before and had the choice to either go buy the correct brackets or use washers to shim it...I wound up making my own bracket it worked great but in the mean time I used a couple washers so I could drive it until the bracket was complete...kind of tough needing to drive the vehicle your working on ...while you make some parts for it....good luck

Backfiring was a timing issue. We advanced the timing to get rid of the backfiring and the engine wouldn't start. I may be wrong but the firing order for a 305 and 350 should be the same. Right now I'm 50 Miles from the van, but the plug wires were not where they should have been, but it did run. I'm at a loss. Currently I have no spark at all from the distributor off of the 305. Even if the timing is off I should have spark. I'd like to nail down the spark issue and then move on to timing.. If you would like more info message me. This van is how I earn my living.

Backfiring was a timing issue. We advanced the timing to get rid of the backfiring and the engine wouldn't start. I may be wrong but the firing order for a 305 and 350 should be the same. Right now I'm 50 Miles from the van, but the plug wires were not where they should have been, but it did run. I'm at a loss. Currently I have no spark at all from the distributor off of the 305. Even if the timing is off I should have spark. I'd like to nail down the spark issue and then move on to timing.. If you would like more info message me. This van is how I earn my living.

Rule no one always use everything off of old engine on replacement.
Water pump and pulleys and crank shaft and all bracket.
Did you do that?
On no spark.
Check all wiring and plug ins and power feeds.
Do you have good even compression on all cylinders?
Is dist shaft still tuning when cranking engine?
Firing order should be the same 305 or 350.
Double check your firing order.
Was the valve adjusted right?
Is the ign coil getting good 12 volts key on?
Where are you checking for lose of spark?
At plugs or out of coil?

What year was the 350 engine?