351c backfiring problem

hi everyone,

im going to try to discribe my problem as best i can. i have a 351c bored 30 crank 10, 4v heads, lunati cam 572 lift, hei dizzy edelbrock torker intake, 650 cfm carb, trick flow push rods tripple valve springs, hypertitic pistons,roller rockers, i pretty much took this engine out of my mustang not runing and bought all new parts to put it back together and mostly high performance parts. well wen i first cranked it up a 8 months ago it ran and idled ok and backfired a little bit then alot it sounded as if i was runing on 6 cylnders. i tood the valve covers off and sure enough my stock push rods were bent im pretty sure they bent right when i cranked it. i bought new trick flow hardend push rods and roller rockers and a hei dizzy and installed them. the car now has more rpm but still back fires out of the headers alot and i have only seen out of the carb once or twice i checked firing order and is corect, the cam is on time the motor shakes alot and gets a lil hot also i dont know where to start now can anyone give me any ideas? i saw was leaking out of the headers a lil but i will tighten those tomorow but i doubt thats the problem actualy i know its not

Are you sure and did you double check the position of your marks when you put the timing chain on? Pull the plugs and see if they are fouled. I had the same thing happen to me. It was driving me crazy for days. I finally pulled the plugs and they were fouled. I changed them and it ran great. Sometimes when you are trying to get a new engine started you will foul the plugs. Also, did you break your cam in? Or did you install a roller cam. I'm asking these questions just trying to narrow it down because it could be so many things.

180 out? waaaay advanced? With backfiring and bending pushrods, id check proper cam placement and dist placement, maybe even pushrod length?

Bring no.1 up and check rotor

well the spark plugs and wires are brand new like i replaced them 2 days ago and the cam is set right i took it apart to check it before i went out to buy more stuff, i thought it was the dizzy and i went hei and it runs better now that i did all that but still back firing, and for the push rods i called summit and i got some to match the cam they arent bent no more,,,,,,,,, and for the cam its a hyd cam with lifters its not roller .... i wil check the marks today again and get bak to you and i will pull the plugs just to see cuz wen it started up it was good for like 1second and then it started pooping again most backfiring is out of the headers

You're running a 572 lift cam with triple springs? That's a lot of spring for a hydro cam. If you feel the need to keep those springs, you should be running 3/8 push rods and guide plates. You don't buy push rods to match the cam - you use an adjustable pushrod to determine the correct geometry and then order that length of pushrod. For example, stock is 8.4 and on my new 4V engine the pushrods needed to be 8.250. I'm not surprised the stockers bent with triples on there - did you check piston to valve contact before closing up the engine? You may have tweaked some exhaust valves.

Also, if you didn't break that cam in you may have flattened a lobe. Especially with your pushrod ordeal.

I would check the timing and choke settings. A lean mixture will cause back firing through the carb and retarded timing can cause over heating and back firing out the exhaust. Double check the firing order be sure to remember that the distributor turns CCW. Everything else has been mentioned.

ya if tried both retarding the timing and everything im just going to by some more spark plugs it look like im running a lil rich they do look a lil worn i dont know y but ima start there and then ill try it again ill keep it posted i just hope its not that big of problem

I hope not either. Good luck.