Carburetor Adjusting Again

Since replacing the intake manifold, the engine has been running rather rich at up to 12:1 while just cruising around and even more rich when accelerating.  I decided I'd make a few jet adjustments today to evaluate the impact.

I checked the current jets and had 60's in the front bowl and 69's in the rear bowl.  The stock setup for a Holley 570 is 54's in the front with 65's in the rear.  This makes my configuration +6 in the front and +4 in the rear.  According to Holley, there is generally no need to increase jet sizes more than +4 over the original configuration.  

I decided to drop the fronts to 57's with 67's in the rear (+3 front/+2 rear).  After making the change, the a/f ratio was good at idle and around 14.5 or so when cruising.  Under light acceleration, it stayed roughly around 14:1 which leads me to believe the front jets are good.  However, when I accelerated hard, I noticed the engine go rich for a second and then quickly lean out and stay somewhat lean at 14:1.  

I decided to start with increasing the rear jet size again back to 69's.  After this change, the engine did not have as much of a lean spike on acceleration but was still rather lean at an average of 13.5:1.  I obviously need a bit more jetting to get the a/f ratio at the desirable 12.5:1 at full acceleration.

I did not really want to exceed the original rear jet size as I feel I would then be moving in the wrong direction.  I decided instead to increase the front jet size to 58's (+4).  After the change, under hard acceleration, the a/f ratio was near 13:1.  However, it seems that at cruise I have quite a bit of variation with the a/f at times going to 15:1.  

My current collection of jets include the following: 54, 56, 57, 58, 60, 62, 65, 67, & 69.  Seems like I would benefit from a set of 70's to run in the rear and leave the fronts alone.  

While I doubt there is much of a restriction, I wonder if I would be better off using a 670.  It is not suppose to impact my ability to have a reasonable a/f ratio.  I just wonder if jet sizes are so much large due to the flow of my engine with the new intake and heads.  If I were to switch to a Holley 670, the stock jet sizes are 65 and 69.  

I'm going to call it good enough for now.  As I drive more, I'll see what additional changes are necessary.