knocking mustang 5.0

[5150coupe]

i have an 89 coupe and just installed a new set of gt40 heads, e303 cam, and 1.7 crane rockers. when starting the car up for the first time there was a loud knocking noise. i thought the valves hit the piston since it was pretty loud, but the numbers show plenty of room for this combo. anyhow, i took one head off and found that everything looks fine and that there are no signs of the valves hitting. i put everything back together and still get a knocking. other mods are c&l 76 mm maf, bbk 70 mm tb, tf track heat upper and lower, and heads are port matched on both the intake and exhaust. i bought spark plugs based on a '93 cobra. even when i retard the timing it doesn't seem to have a possitive effect. any ideas?

[DaLe five OH!]

bent push rod? bad rocker? loose rocker? bent valve?

[Dark_5.0]

Take off all of the rockers and pushrods and inspect eveything. Look for bent pushrods or damaged rockers. The rockers are pedistal mount right???

[5150coupe]

i ended up finding out that it was just a timing issue. just backfiring...but now i have a couple other related issues. i can't seem to set the timing to 14 like it was before. at 14 i get backfiring and it won't idle or run well unless it is advance way to high at about 22-25. it doesn't seem to ping even though it is high, so i thought maybe the timing marker is off or something, but it looks to be at the same location as my friends coupe. i'm going to put it on the computer and start checking codes.

[USMC302]

Sounds like you a tooth off. Pull the dist, set engine to TDC, and restab it. Double check your ignition wires as well to make sure you don't accidentally have one crossed.

[goodyear1984]

13726548 firing order and i think u point the rotor to the ft drivers side upper intake bolt its like 1 oclock