Here’s a similar build: Flat top 446, sidewinder heads flowing 290(same casting as the Toth head), 250/254-108 SFT cam with Chevy lobes, 1.5rr, rpm, 850DP carb, 2-2 1/8 x 4 dyno headers. Notice the difference in VE, and bsfc.
Those are good numbers, especially with the large headers!