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Charter Member
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870 Posts
Discussion Starter · #1 ·
My question is after I complete the build with the EFI,If for some reason I dont like it,will it be difficult to convert it to carb???I'm just unsure if I should go with the EFI ,when I took it out of the donor it wouldnt Idle under 1000,it would just stall out anything under 1000.The engine does have some work(302 Trick flow aluminum heads,trick flow intake and upgraded cam,I dont know the exact specs on the engine build as I did not do it myself,it was done by the previous owner who had all the rebuild work done at a shop,the owner put the engine in then couldnt get it running till I got my hands on it.
Whaddaya think fellas???
 

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Super Moderator
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29,535 Posts
Different dizzy
Different fuel pump
Different regulator
 

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Premium Member
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5,159 Posts
I did mine in about a half of day. I used the stock fuel pump and a by-pass regulator followed by a standard regulator. A different distributor and coil and thats about it. You have to ground the fuel pump wire going to the ECU to get the pump to run.
 

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Registered
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11,828 Posts


for the pump, you can do what Lex said, or you can switch out the motor itself for a lower pressure Master Brand Electric E2025, $45 at Autozone, and add an external fuel pressure regulator. i used an inexpensive Holley non-return style fuel pressure regulator.
 

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Junior Charter Member
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815 Posts
Most information I have seen states to use a 3/8" or larger fuel line for a carb. Any issue with using the stock 5/16" EFI fuel line?
 

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FFR Craftsman
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5,834 Posts
Um, just to be sure you have everything:

-Intake manifold :D
-Carb of course
-Possibly a linkage kit (i.e Lokar)
-Gaskets for both carb and intake manifold
-Air cleaner
 

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FFCobra Craftsman
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24,711 Posts
Lurker-I'd position the fuel pressure regulator relatively near the carb.Run the stock line at it's normal 35-40 psi to the reg,then run the 6-7 psi coming out of the reg to the carb in 3/8 inch.
 

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FFCobra Fanatic
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12,975 Posts
Lurker not sure I would use smaller then 3/8" line for a carb motor useing machanical pump. Useing less psi it needs the larger size line. Electric pump 5/16" would be ok.

Eric no big deal swapping over to carb later once installed. Only major mod would be if wanting a machanical pump instead of electric pump and regulator set up. Removing the timing cover to add pump excentric should be done now since its easyer then when engine is in car.
Do some basic trouble shooting and adjustments to the efi on car now. may find it only a minor problem to make it work with your engine combo.
TBS,adjustment,timeing,vacum leak,ect. Any could cause hi idles problem.
 

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Premium Member
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5,159 Posts
As I said Earlier I'm running the Mustang pump with 2 regulators. I'm using the stock 5/16 fuel line. The by pass regulator would only get the pressure down to 9 psi. With the second one I got it down to 5 psi. I've had no fuel starvation problems whatsoever with a 650DP but my engine is stock on the bottom end. This includes long full throttle runs and even in heavy traffic on very hot days no vapor lock.
 
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