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Dead Parrot · 06-23-2020, 02:15 PM

I have a 75 C10 with a similar setup. Stock 350 crate motor/TH350. Performer manifold(spread bore), earlier 1405 eddy carb, no return mechanical fuel pump. 1" aluminum 4 hole spacer advertised to improve low end performance. Ceramic coated headers. Never had a vapor lock or similar issue. It will evaporate off some of the carb bowl gas if it is hot which will give a few seconds of cranking before start.

I still have some exhaust crossover flow but no riser valve to get stuck.
7 blade fan, 3 row radiator, OEM shroud, and standard duty fan clutch 195* Thermostat.
Only emissions are PCV and THERMAC.
About 12* initial advance, vacuum advance connected to manifold vacuum. As much initial as it will let me do before hot hard to start happens.

What is your initial timing? Most stock 350's like lots. More idle timing means less idle fuel needed = cooler engine and engine compartment.
How many blades on your Fan?
Thermostat temp?

06-23-2020, 02:15 PM	#6
Dead Parrot Registered User Join Date: Aug 2012 Location: Oklahoma City, OK Posts: 2,675	Re: Vapor lock/percolation? I have a 75 C10 with a similar setup. Stock 350 crate motor/TH350. Performer manifold(spread bore), earlier 1405 eddy carb, no return mechanical fuel pump. 1" aluminum 4 hole spacer advertised to improve low end performance. Ceramic coated headers. Never had a vapor lock or similar issue. It will evaporate off some of the carb bowl gas if it is hot which will give a few seconds of cranking before start. I still have some exhaust crossover flow but no riser valve to get stuck. 7 blade fan, 3 row radiator, OEM shroud, and standard duty fan clutch 195* Thermostat. Only emissions are PCV and THERMAC. About 12* initial advance, vacuum advance connected to manifold vacuum. As much initial as it will let me do before hot hard to start happens. What is your initial timing? Most stock 350's like lots. More idle timing means less idle fuel needed = cooler engine and engine compartment. How many blades on your Fan? Thermostat temp?