[olddog]

I never hear much talk about intake charge temp around here, but this can be the cheapest Hp you can buy. Air density is proportional to the absolute temp (use the Kelvin scale). If your under hood temp is 140 F (assuming your carb is pulling in under hood air) and you can reduce that air temp to 90 F, air density increases ~9%. So a 335 Hp 428 would get a 30 Hp increase. Now the air temp that actually matters is after it is pulled into the cylinder, and the air temp increases coming through the intake manifold. So just because you drop the air temp entering the carb by 50 F, it doesn't mean there will be a 50 F drop when the air gets to the cylinder. Also a 335 Hp 428 is a number that was corrected to what the engine would have made at sea level and I think 70 F air, so you most likely are not producing 335 actual Hp where you are at.

But the bottom line is that a good air gap type intake (not sure about availability for FE) and getting outside ambient air to the carb can be a big help. This is not going to break the bank and requires little modification to the engine.

Point #2. Most engines have not been tuned to get the correct AFR and best timing. There is usually Hp left on the table that can be grabbed by a good Dyno tuner. Dollar per Hp gained may not be so cheap, but after an intake and routing cool air to the carb would be a good idea anyway.