Yeah I have heard the same that are are a ok head but work alot better if somone removes alot more material I guess edelbrock leave alot of metal to port on and it was a little hot outSome food for thought.
Note that your horsepower is uncorrected for weather conditions. Was it a hot humid day? Was it stormy? Are you at sea level?
Corrected horsepower is adjusted to standard temp/pressure/humidity/altitude by a factor called air density. For example, if air density is 90% then expect "corrected" horsepower to be 10% more in a naturally aspirated engine. It's all about how much oxygen is in a given amount of air that the engine is ingesting. Irregardless of the fuel mix, amount of oxygen present in the air is the limiting factor in production of power. This is how superchargers and nitrous make more power - by adding extra oxygen to burn more fuel. Here is a site that gives historical as well as forecast air densities at many tracks around the country. Air Density Online - Engine tuning weather If you know the day of the dyno, you should be able to get an idea of everything from the Air Density Online site except for the air inlet temp (maybe you have that logged).
Also pulling down the numbers are the water pump, alternator, and the cooling fan. Taking the belts off made about 30-35hp difference on the dyno for me. Then I went to electric water pump and fan.
With my 383 (10.3:1, AFR 195 heads, Air Gap, Quick Fuel SS830) I went 345 HP uncorrected (355 HP corrected) at the beginning. 371 HP uncorrected (391 corrected) with electric fan and water pump. 403 HP uncorrected (405 corrected) with gasket matched Vic Jr and tuning carb. 419 HP uncorrected (448 corrected) with Crower 00307 FT Solid cam, 1.6 rockers on intakes, and tuning carb. Always open headers. Note these are 4 different dyno sessions, so percentage of correction is different for each set of weather conditions. 60' ET was 1.49 1/4 mile was best 10.85 @ 122 mph. Vehicle weight was 3220 with me in it. Was a Dynojet Dyno. Went from 11.80s to 10.80s. I do have a custom converter from A-1 and a TH350 - 3.73 gears - 28" tire. Crower cam was still increasing power at 6750 but I kept that as a redline. Original XE274H was done at 6200 in my setup, but that was higher RPM than published.
Haven't heard a lot about Vic Jr. heads or know which ones you have. Not sure how many people are using them or why. Supposed to have some CNC machining but not as much as the AFRs.