I have an engine from a 1971 Camaro in my 1965 Chevy 1/2 ton stepside. It began to backfire a few weeks back through the exhaust when the weather got cold out. This truck is garage kept during the evening hours. When I started it, it would take about 10 minutes to warm up to the point where it would run right. Then one Monday about a week ago now, it would not start at all!!! I have since changed out the points, condensor, and the coil...the cap and rotor look good so I have not replaced them as of yet. I turn the key and the starter turns and turns but there is NO fire what-so-ever. CAN ANYONE HELP END MY NIGHTMARE!?