So I finally finished rebuilding my engine and got it back into the car this week.
I installed the ls2 timing kit, ls6 cam-oil pump-valley, rebuilt the heads with ls6 springs and seals, and installed pacesetter coated lts.

I got the radiator back in this morning, installed all the coils ect. Turned it over a few times without the coils or fuel pump activated. Afterward I started the engine and got to see a nice plume of white smoke. At first I thought it was just oils bnurning off, but apparantly I have a exh header leak on the pass side.
Decided to let it run a liittle longer to warm up.

After about 10-15 mins I got a couple of backfires. At turned the engine off and checked everything back out, topped off the coolant and restarted the engine. No leaks but now I'm getting the p0300 code and nearly constant backfires. Any idea where to start? I removed the valve covers and could not see anything that look out of the norm.

 

Did you check all the plug wires? Make sure the header didn't burn one and that they are snaped on all the way. Also did you check all the spark plug gaps before installing them?
Is the p0300 code a random misfire code?

 

I'm sure that none of the wires are burnt. I will double check them.
The plugs were gapped correctly.

 

Did you fix the leak on the headers? How did you extend the o2 sensor wires? Can you tell which cylinder is misfiring?

 

Do you have a stall?
Have you gotten a tune?
How about a crank or cam position sensors?
Did you kink one of the wires maybe?
Check your coils too!

Goodluck and keep me updated.

 

I tightened the headers untill I thought the bolts would break. I did put o2 ext on.
I noticed that when I installed the coil harness on the drivers side, I may have installed the harness backwards. the grey main plug would not reach the clip that holds it on the valve cover. I'm thinking that if I installed it wrong, the drivers side coils are firing in reverse order. Make any sence?
I have not run the car again because of the popping and I live around alot of 80 year olds.
I have no way to tell which cyl is misfiring. I was planing on getting the car tunned on sat if the engine ran ok.
Thanks for the help so far guys, I'll keep u posted.
The crank and cam sensors are connected and had no problem before the build. I made sure to be carefull around them.

 

Raining today

 

Ok I went in the rain and reversed the coil wiring. The car runs great now.

 

Good Job!!! I bet you feel a lot better now!

 

Yea...except that i forgot to install the tranny dipstick tube before I put the block in. I tried every which way to do it.........now with a kick in the nuts....Its at the stealership getting installed on monday.

 

And I thought GM Murphy proofed the connectors and harnesses so that couldn't happen. Oh, well. Next time use a digital camera as you pull parts off.