Backfire through intake? 5.0

[thorsteinarg]

Hey guys, just wondering if you had some ideas for me, soo, the motor itself I tore down, changed head gaskets and all the gaskets above that, timing chain also, and put stiffer valve springs and a b303 cam.
Now I have the motor assembled, but when I start it, it manages to ignite the fuel in one of the drivers side cyl bank, but nothing comes out of the other header. It just backfires through the intake.

Ignition has been synchronized and is spot on, at first I thought it was just the cam synchronizer timing, so I did it twice. No change.
Is it possible for me to have gotten the timing on the cam itself 180* wrong when I changed the cam and timing chain? Its been 2 years since I did it so the memory is not fresh.
All ideas welcome!
Thanks!
:Edit:
When I did the cam synchronizer timing, I used the timing marks on the crankshaft pulley, with nr1 piston at compression stroke, and aligned it with the pointer on the crankshaft sensor, this procedure requires me to use the pointer on the crankshaft sensor correct?

 

[Mbrooks420]

I'd surely think your timing is way out. If it were remotely close, something would come out of the exhaust. Likely you are 180 degrees out like you suspect.

 

[thorsteinarg]

Nothing seems to solve this issue! Tried flipping the cam sensor 180 degrees, nothing. Am I timing it the right way? With n1 piston on compression stroke, and aligning the arrow on the crankshaft sensor on "0" on the camshaft wheel. Still nothing.
Running a b303 cam from a mustang, even tried changing the firing order. Nothing.
The front balancer I think its called? It can only be mounted one way right? So "0" on it has to be right.. And I am supposed to align it with the arrow on the crankshaft right?
Starting to run out of ideas here..
Car has b303 cam, bbk shorty headers, gt40p heads with stiffer valve springs.
Also, I am running a 1996 computer so pats would not be a problem. 1999 motor most likely.
All ideas greatly appreciated!

 

[vroomzoomboom]

start from the beginning and try it this way. pop the #1 plug out. either have you or someone bump the motor with the starter with your thumb over the spark plug hole (#1 is the front most cylinder on the passengers side, if you knew that already, just wanted to verify with you. not trying to make anyone look dumb or anything like that). when the air pushes your thumb or finger which ever you use off the hole, you are now on the compression stroke. use a coat hanger and put it in the plug hole so it rests on the piston. rotate the motor until you feel the coat hanger want to go down. as soon as that happens, turn it back the other way until you feel want to go down again and split the different in rotation. you will be at TDC. double check the mark on the balancer to the pointer. then also double check the cam sycro. if those are fine then double check your plug wires for the firing order. if i remember correctly, a HO mustang 302 is the same firing order as a explorer. now if all those check out, you might want to check compression. it might be possible you have a valve hanging open, and you will have to reset your valve springs.
\this is all a PITA to do. trust me, its happen to me more then once.
let i know how you make out.

 

[thorsteinarg]

Verified the timing a couple of times. Even did it all over again. Compression test sounds good, besides the fact that taking these bbk shorty manifolds, wrapped in heat reflecting thingy, on the gt40p heads, is a biiiig pain in my a$$. I have thought of the possibility that a intake valve is open, matches my problem perfectly.. But my head tries to deny that fact

 

[thorsteinarg]

On these engines, the timing marker is the arrow on the crankshaft sensor correct?
Compression test -》 Verify engine timing -》
Remove heads, inspect valve clearence.
Guess this is what I am down to .
Then hopefully

 

[vroomzoomboom]

On these engines, the timing marker is the arrow on the crankshaft sensor correct?

yup