What's the bottleneck in my engine?

[ItBites]

I'm not up to speed on Ford heads, but I noticed a few things I would do differently in general since an engine is an engine:

2.05/1.60 valve sizes are a little small for 425 ci. (I use 2.30 for intake size on 427 ci BBCs). Your valves would make big low RPM power however.

750CFM, while OK by the usual formulas is a little small for PEAK (dragstrip) power in 425 ci. See other posts I have made regarding the relationship between max power and manifold vacuum and charge density at the valve. I use 1000 CFM throttle body on 427 ci.

.544 and 230 deg (I assume at .050 valve lift) is indicative of a low end power cam (short duration and low lift), but 110 deg lobe center is a little narrow and will produce more overlap similar to a high RPM cam. This cam seems to be a contradiction of itself from the manufacturer?

while .544 and 230 deg will work with 10.5:1 CR, the 110 lobe center wants higher compression and higher RPM. I would use 114 lobe center with 10.5: CR.

I think the Vic Jr is a high RPM manifold, and with 10.5:1 CR and 230 deg you can't effectively use that manifold.

210 cc intake runners in a BBC would be a low RPM power setup with good throttle response. I assume Fords are comparable (?)

In summary, I think you have some mismatched parts. My suggestion is to use the 10.5: CR and heads and go from there (since those are the most expensive components). The 10.5:1, 210 cc runners, 2.05/1.60 valve sizes just scream to me low RPM power with good throttle response. Now how to get the rest to match(BTW 600 HP is likely not where you are going with those heads/valve sizes and CR):

I'd put in a cam with maybe around or less than 230 deg at .050, but I'd up the lift to ~.620 and 114 lobe centers. This cam will have enough lift to fill the cylinders nicely (even with the little valves), a short duration to work with 10.5:1 and along with the wider LC, will tend to make the engine think it has higher compression (dynamic compression).

Then I'd go to a dual plane manifold. Maybe Air Gap or Stealth and if they have a separated plennum, I'd machine the divider out to get a combined plennum below the carb. Id also go to an 850 double pumper style carb.

I saw a suggestion to run to 7000 RPM earlier. I wouldn't with your CR and valve size. 7000 requires more overlap and your low static CR doesn't develop enough dynamic CR to work well with a lot of overlap.

I think you'd be much happier to try to work with the 10.5:1 CR and small valves and build more power on the low RPM end.

My $.02