Txcorruptor

Installed new E303 cam in my sons project. New double roller timing chain. New roller lifters and new push rods. New water pump and high volume oil pump. I bought it pulled apart with damaged cam due to collapsed lifter. Got it all together and it runs. After some vacuum leak issues it idles and has some power. After a test drive it showed potential. Then it suddenly decided to sit on its *** when you give it throttle. Now it doesn't want to idle. Now when you give it throttle is sputters and backfires. Any ideas would be appreciated.

mjr46

check the distributor.........make sure the roll pin in the gear hasn't sheared....if it did, could have an oil pump issue......sounds like timing is off.....and if it is, it didn't just go out on it's own.......to verify, point a timing light at the balancer and with spout out check to see where base timing is at and if it is erratic....erratic timing could be a result of a distributor issue or other things. Also I assume you installed the correct valve springs on the heads for that cam as well and if so set installed height correctly???

1TUFF302

I have the X cam in mine and I had to fly cut the pistons because of to little piston to exhaust valve clearance,lets not forget I all so have a gear drive in it too.kind of sounds like you have a bent valve with the back fire or you your vac leak came back.

67LimeCoupe

I had a distributor bolt come loose while on the highway, bucking and backfiring and finally quit. Double check the timing, newer roller 5.0s need steel geared distributors, if yours wasnt it couldve eaten itself.