300 carb vs 300 FI diffrences
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300 carb vs 300 FI diffrences
Aside from the fuel system is the fuel injected 300 different then the 300 carb engine ?
I know when the 460 went to FI they changed the head design, but does anyone know about the 300 what changes it might have had ?
I know when the 460 went to FI they changed the head design, but does anyone know about the 300 what changes it might have had ?
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Joined: Dec 2007
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From: Boise, Idaho
Quick things I can think of.
There's no opening for the fuel pump in the block on the EFI motor, since it was moved to the fuel tank.
The head has 16 bolt holes for the intake/exhaust instead of 13. The 3 extra are insignificant though, since they're mostly there to hang the manifolds from during installation since there's 3 pieces instead of 1. Sped things up in the factory.
The EFI head also has quick burn characteristics added to the chambers, but will readily bolt onto any carb engine.
The oil pan is slightly different and can use a 1 piece rubber gasket (jealous).
They also went to serpentine belts.
Other than that, they're pretty interchangeable. I may be forgetting one or two things.
There's no opening for the fuel pump in the block on the EFI motor, since it was moved to the fuel tank.
The head has 16 bolt holes for the intake/exhaust instead of 13. The 3 extra are insignificant though, since they're mostly there to hang the manifolds from during installation since there's 3 pieces instead of 1. Sped things up in the factory.
The EFI head also has quick burn characteristics added to the chambers, but will readily bolt onto any carb engine.
The oil pan is slightly different and can use a 1 piece rubber gasket (jealous).
They also went to serpentine belts.
Other than that, they're pretty interchangeable. I may be forgetting one or two things.
Posting Guru
Joined: Apr 2003
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From: Venezuela
A few more things...
Since there is no fuel pump at engine, fuel pump lobe on camshaft is present but not machined. It can't be used on carby ones
EFI Head has a higher compresion ratio so should't be used on carby application or knocking problems will appear.
Since there is no fuel pump at engine, fuel pump lobe on camshaft is present but not machined. It can't be used on carby ones
EFI Head has a higher compresion ratio so should't be used on carby application or knocking problems will appear.
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Joined: Dec 2007
Posts: 7,987
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From: Boise, Idaho
Haven't heard that one before. People use EFI heads on carb engines pretty frequently. The 240 head has higher compression than the 300 head, and it's a sought after bolt on for a performance upgrade.
Posting Guru
Joined: Apr 2003
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From: Venezuela
Yes right, when you are doing a performance upgrade you should not modify just one thing since everything on engine is related so... using a higher compression head, require also a dizzy re-curve and/or a different fuel strategy to control knocking.
There are countries like Venezuela or Colombia where Ford never assembly EFI 300, so any truck with 1987 or newer 300 engine comes from factory with a separator plate and double head gasket + longer push rods. All this just to reduce the compression then Ford can still using same distributor and carburetor with no calibration modification.
There are countries like Venezuela or Colombia where Ford never assembly EFI 300, so any truck with 1987 or newer 300 engine comes from factory with a separator plate and double head gasket + longer push rods. All this just to reduce the compression then Ford can still using same distributor and carburetor with no calibration modification.
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