I just got her fired up after a motor and tranny swap and I'm getting poping and through carb and some occasional backfire through the rear.
I have a 350 with 10.63-1 pistons with 62 chamber heads, but I have 72 chamber sportsman heads so my compression is more like 9 1/2 -1, an xe268 cam,crane 1.5 roller rockers with a performer rpm intake and a 1" spacer plate, holley 750 doal feed carb, mallory unilight vaccuum advance,hooker comp headers.
I have adjusted the carb and have 12# vacuum, I haven't checked the timming yet as I am just trying to get it to run clean by ear. I just adjusted my rockers down and when she cools down I am going to start pulling the plugs to see how their looking next. I couldn't find any vacuum leaks. It sounds good when shes not poping as its not always there, anybody got any suggustions where eles to check? thanks

Was the cam indexed when assembled? Also popping through the carb ... means firing while intake valve is still open maybe rockers too tight, physical timing out, distrib. timing out... etc... just some things to look at.

If the timing is retarded it will pop and cough a lot.
David

The unilite has the photo eye pick up......right? I had one. They suck. Either your not getting enough gas or the unilite is your problem. Get a Q-tip and some Alcohol.....wet the Q-tip wth the alcohol and take your dist. cap off and swab both sides of the photo pick up eye on the distributor. Swab both sides good and put it back together. Sometimes the lens gets fogged/dirty and will not pick up correctly. I carried alcohol/windex and Q-tips with me all the time. No rime or reason on how/why it would fog/get dirty. Hope this helps. graemlins/thumbsup.gif

Set the timing - that's pretty basic to proper operation. How did you lash the valves?
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