So this is my first post and I figured that I"ll make it a good one. I have a 07 monte carlo ss 5.3 50,000 miles that I just finished last Saturday. the list of mods go on as follows... ( I did all this at once)

lunati cam 21460701
lunati valve springs 73925-16
lunati lifters 72332-16

gm block off plate dod or (active fuel management) gm 12570471
Thorley headers thy-340-c
k&n cold air intake
diablo trinity I 1000 tuner

I'm having a couple issues... (I have to go through emissions)

im getting a p o 300 code which is a misfire
im getting that only in the morning at cold start ups.. so I clear the code and it's gone and it doesn't come back until the next morning starting it cold.
so both my evap and my heated o 2 monitors are not ready so no pass emissions.
Has anybody done a cam change and had this same issue any input would be appreciated. im leaning towards changing the injector slope first...

oh btw this thing is sick

 

Here's some pics

 

 

Having not done a cam swap on one of those engines and never having the start up problem that you are having with the codes I can't answer your questions.

But.....the motor looks bad a## I hope you get it all figured out

 

Thanks... I have alot of blood sweat and tears in this ls4...
I will say it does not lack any power... im hoping for some input on which way I need to go with it. I figured someone on here has had this same issue.

On another note anyone that is wanting to cam a ls4 be prepared to get an aftermarket hydro boost for your brakes...
Ran into the problem that I have a big cam and under wot it steals all the vacuum. Meaning if you floor it and have to stop asap its not going to happen. Trust me not a good feeling at all.
Im also wondering if anybody has the diablo trinity tuner and if so where they have the injector slope set at. What im thinking I have to do is fool the computer that I have larger injectors.
Again any help is appreciated.
More pics to come
Thanks matt

 

That looks amazing man! I'm only aware of one other Cammed LS4 and that's a Grand Prix on youtube. Can't wait to see more pics of this buddy and def need a sound clip!!!!

 

Does this happen every cold start, random misfire? Do you have a way to watch misfire counts during a cold start. Do you have any base line dyno numbers before all this work? Is there a tune on this setup? Dropping the craddle is the smart way to do all the mods to these ls4's, nice job.

 

My only assumption could be the tune, it might be looking for fuel at start-up. Do you have any ways to monitor this stuff?

 

I figured that a lot of monte carlo fanatics have done a ls4 cam swap. thanks a lot I will get more pics on here and a sound clip.

 

As far as every cold start yes it has. I got the car going on Friday night 5-30-14. Saturday started it and got the 300 code. Sunday started it and same thing. Monday I knew better and I started it and took off right away I didn't let it idle at all and it never came on. I have a solus to watch misfire counts and the last time it was cyl 6 and cly8 6 had 4 mis and 8 had 6. I do not have any base line numbers at all. as far as the tuner no I have the dod off and it is on the stock setup. yes dropping the cradle is the way to go.. you have about an hour on top and 45 min on the bottom and cradle comes right out. also the only way to get the headers on, and the cam unless you want to drill a hole into the passenger side of the car and weakened the whole structure which I would never do...