Guys,
I'm in trouble again. Every now and then when I start the engine when it's cold ( only cold ) the engine will backfire through the carb. It's a 390 with new everything. I've tried the unilite distributor and the point distributor with the same results. The timing is on 6 degrees. It has 9.3 to 1 compression. The engine runs strong after startup without any problems afterwards, just the initial start. During the first 2000 miles after building this engine, I didn't have this problem. I also used ARP Stainless bolts in everything except the rod and head bolts and I have had to retorque the exhaust manifold bolts once. I haven't checked the intake yet. Also the float level on the holley 570 was checked and found OK. The engine seems to run a little rich but I'm still getting 15 mpg around town and goosing it quite often. The comp cam I used keeps the exhaust open a little longer than the stock 428 cam did, I don't know what that would have to do with it but I thought I'd throw that information in also. Like I said, everythings new so what do I look for.
Also, is there anything I can put on the ARP bolts in the exhaust manifold to keep them from loosening again.
Thanks,
Jim

 

i've used and been told to use thick teflon tape...i tried and had good success!

 

Sounds like choke adjustment to me.

 

Thanks Rusty and 8Mile,
The electric choke was adjusted down pretty tight and come to think of it, when I didn't set the choke before turning the key it wouldn't backfire. I've put just enough spring in it to close the choke when cold.
The teflon tape will go on the exhaust manifold bolts next weekend.
Thanks Guys
Jim