252@ 50 is dinky for a 4 inch stroke motor. The stroke eats duration a ton.
I had a 10.70 combo few years back similar to what you are doing, and almost identical weight.
416, about 11.5 compression. Mildly ported eddies. Went 275@600
Weiand excellerator single plane. TTI 1 5/8 to 1 3/4 step headers( bigger would have been better)
1000cfm 4150 carb. 727/ 8 inch convertor. 4.30 gear, 28 by 10 tire
Cam was Dwayne Porter specced. 260/266 598/623 with 1.6 rockers
Car would have run better with bigger headers, more headwork. Shifted it at 6600, nosed over a little last 100-150 foot in the 1/4 mile. Small heads for that cubic inch. Went right at 125 mph
I drove that combo everywhere. 70 mile round trip jaunt to the track on several occasions on the QTP’s i always had on it.
Get a bigger cam. Trust me. Your a good 10 degrees to small
My cam in my current 360 is 260@50 and its barely 10.5 to 1 and it runs good for what it is. 408/416 is a MUCH bigger motor
