They make a valley pan without openings where the heat riser passages go into the intake.
383 hard to start when warm
- Thread starter lorny
- Start date
Check your carb float level again. I swear to god my old AVS(rebuilt 8yrs ago) & Summit electronic distributor lights off faster than EFI when warm, don’t even touch throttle. A dead battery would still start it!
JG71B
Well-Known Member
Just did this in my 71 with a stock B motor and headers. *** load of heat. What worked for me, fuel filter with a return to the tank, re routing fuel line the same path as the factory did and insulation under the intake. No issues since. 90* heat, not a problem
lorny
Well-Known Member
wr do you get fuel filter with return and for what years and model
JG71B
Well-Known Member
Ebay, WIX 33040
70bigblockdodge
Well-Known Member
Alright I'll add a few details of why return works.
1. It keeps the fuel moving when your idling, moving slow in traffic, underhood temperatures at there highest. This keeps fuel near a very hot heat source from boiling in the line. On the suction side of the pump fuel (mainly ethanol/alcohol boils at just over 100°f) boils at lower temperature because it's in a lower pressure environment in fuel line going to pump.
2. When you shut the car off fuel stops moving, or at least it should stop moving. The fuel that was under pressure from pump to carburetor needle and seat 5-7 psi stays pressurized in the line for a while to long time depending on condition of you components. When engine is hot, weather is hot, air not moving in engine compartment the fuel in that section of line gains even more pressure due to temperature rise. Then it climbs to a point where it pushes past the closed needle in float bowls causing them to overfill which in turn leaks into the manifold causing a flooded condition.
The side tap/return on the filter has a orifice in it to bleed some fuel back to tank (keeping it moving), not allowing it to hot spot on the lines and boil (vapor lock). When car is shut off it allows the pressurized fuel to bleed off rather than forcing it's way into the float bowls and flooding the engine.
Some carburetors are not happy with heat. The one we have had trouble with was a old Holley 3310. When it was doing the dribble thing and you stuck your finger on the vent it would literally start squirting out of the accelerator pump nozzles.
With today's gasoline, ethanol, no surface tensioner additive to prevent easy evaporation, and a dozen other additives that were not in gasoline before EFI modifying the fuel system is not a bad thing. Any removal of heat from carburetor/manifold or lines is a good idea. Not many of these cars running in winter/cold. Gasoline vaporizers so well now to reduce emissions, that a hot manifold is not really needed.
1. It keeps the fuel moving when your idling, moving slow in traffic, underhood temperatures at there highest. This keeps fuel near a very hot heat source from boiling in the line. On the suction side of the pump fuel (mainly ethanol/alcohol boils at just over 100°f) boils at lower temperature because it's in a lower pressure environment in fuel line going to pump.
2. When you shut the car off fuel stops moving, or at least it should stop moving. The fuel that was under pressure from pump to carburetor needle and seat 5-7 psi stays pressurized in the line for a while to long time depending on condition of you components. When engine is hot, weather is hot, air not moving in engine compartment the fuel in that section of line gains even more pressure due to temperature rise. Then it climbs to a point where it pushes past the closed needle in float bowls causing them to overfill which in turn leaks into the manifold causing a flooded condition.
The side tap/return on the filter has a orifice in it to bleed some fuel back to tank (keeping it moving), not allowing it to hot spot on the lines and boil (vapor lock). When car is shut off it allows the pressurized fuel to bleed off rather than forcing it's way into the float bowls and flooding the engine.
Some carburetors are not happy with heat. The one we have had trouble with was a old Holley 3310. When it was doing the dribble thing and you stuck your finger on the vent it would literally start squirting out of the accelerator pump nozzles.
With today's gasoline, ethanol, no surface tensioner additive to prevent easy evaporation, and a dozen other additives that were not in gasoline before EFI modifying the fuel system is not a bad thing. Any removal of heat from carburetor/manifold or lines is a good idea. Not many of these cars running in winter/cold. Gasoline vaporizers so well now to reduce emissions, that a hot manifold is not really needed.
Last edited:
felpro 1214 on a lowdeck.I'm pulling the intake today to eliminate crossover on the 383 my daughter races. Going to an M1 with no crossover. Hoping it will clean up some inconsistency
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After years of having hot start issues with stock A bodies with slant sixes, I was surprised at how easy my first GTX was to start hot. The slant sixes had no return line, but in '68, the factory started installing them on GTXs and R/Ts. A few of the seven GTXs I've owned over the years had the factory return blocked off, and gave me hot start issues. Plumbing in the factory vapor separator/filter always solved the problem.
JimCoronette
Well-Known Member
Try this first. Push the pedal down slightly while cranking it. Maybe an inch or so.
Stonehengeheel
Well-Known Member
I had the same problem with my 440 until I installed a high torque starter. No more warm start problems. The starter speed really helps.
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