We use the factory thermoquad amd manifold even thou it is a major
mismatch to the heads.
I still race a 318 small valve 302 4000Lb Aspen /Wagon with stock 390 lift cam and stock compression/
heads/manifold/ carb when I am not feeling good enough for the faster cars. I was shocked how well the stock 302 flowed compared to
my best 202 X heads up to max lift of 390 on the same bench even with the tiny valves (Hint: well over 200 CFMS's with the
right valve job.
The Wagon held the O/SA NHRA record @ 11.83 @ 109MPH. complete with Roof Race and Air Deflector
for years!
To see it Google: John Irving Drag Racer