Won't start...

[fuzz]

I've built a lot of small block chevy engine in my long life. But this one has me stumped. It's an 89 5.7 out of Chevy truck. Bought it from a Chevy dealer mechanic that said it was low mileage from a wreck. I tore it down and inspected everything. Standard crank, standard bore. Cam bearings look good, valves look good but I cleaned and lap them in. Cut small ridge from each cylinder and ran a glaze breaker thru them. Assembled new rings and bearings, put after market [no name] cam with new lifters, new timing set. Dropped it in my s10 project and set timing and valves. Carb came off a good running motor, dropped in a new distributor. Primed the oil pump and fuel line to carb. Start cranking but it won't start. Checked all plug wires for spark, pulled valve covers and checked rocker lash again. All looks good, won't start. What I get is an occasional backfire. It spins over like it has no compression but I can't do compression check due to headers in the way. In fact I have to pull the headers to install plugs. I spent better part of one day checking stuff. Then I pulled the motor and dropped in another new motor I built for a different project.. The new motor fired one the first try. That smoothed my ego some.
Pulled the engine apart looking for something wrong. Noticed the head gaskets fell apart, steel rings around the cylinders looked good but the stuff between disintegrated [cheap no name gaskets]My guess is the cam is ground wrong or the key way in the cam gear is machined wrong. Anyone want to take a guess?[S

 

[dogpatch1]

cam degree

my first guess would be cam degree off. that crank gear having three key way slots it would be easy to do., next time use a cam degree wheel, or a stock lower timing gear set cam timing and intitial valve lash on the engine stand if you didnt, hope you get it fired.