Intake compatibility
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Intake compatibility
I've got an '89 F150 4x2 4.9I6 with the mazda 5speed and 145k miles. As my user name implies, I used to be quite the Chevy guy until I bought a Ford and have loved it UNTIL now. I would like to 'downgrade' to a carb setup because the engine has been running so poorly lately that it has almost gotten me into several crashes. I have given up on the efi because I think there are several things wrong with it (various sensors broken) and I don't know how to diagnose/fix them. I know this because it has stored so many codes that I am lost. I also prefer simple machinery to more complicated things 
.
I want to know if the head on my engine is compatible with an older intake manifold for a carburated setup. Ideally I'd like to put on one of those offenhauser or clifford manifolds that will accept a nice simple 4bbl carb.
So what I'd like to know is simply if a manifold for a pre-86 300 engine will bolt up to my '89 engine or not. You guys are great and thanks in advance.
.I want to know if the head on my engine is compatible with an older intake manifold for a carburated setup. Ideally I'd like to put on one of those offenhauser or clifford manifolds that will accept a nice simple 4bbl carb.
So what I'd like to know is simply if a manifold for a pre-86 300 engine will bolt up to my '89 engine or not. You guys are great and thanks in advance.
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Joined: Jul 2003
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From: Chicago, IL
Intake compatibility
Hey! wanna swap?? lol i'm actually wanting to upgrade to EFI due to its reliability and fuel economy. I'm real good with diagnosing EEC-4 EFI problems (i've owned 6 Fords with the EEC-4 EFI setup and worked on a million others) so getting it to run right its no biggie for me.
i'm also interested wether or not the heads are the same. if the heads are the same, intakes will boltup.
keep in mind when switching to carb:
you will need to remove your fuel pump. luckily f-series had them on the frame rail rather thn inside the tank, at least in the '86-91s.... simply bypass the pump. after bypassing the pump, you will need to buy a mechanical fuel pump. theoretically the cam and the poening on the block should be there ready for a mechanical fuel pump.
also just for reference, '86 300-6 still had the 1bbl carb...
i'm also interested wether or not the heads are the same. if the heads are the same, intakes will boltup.
keep in mind when switching to carb:
you will need to remove your fuel pump. luckily f-series had them on the frame rail rather thn inside the tank, at least in the '86-91s.... simply bypass the pump. after bypassing the pump, you will need to buy a mechanical fuel pump. theoretically the cam and the poening on the block should be there ready for a mechanical fuel pump.
also just for reference, '86 300-6 still had the 1bbl carb...
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Joined: Jun 2000
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Intake compatibility
There are some minor differences in the EFI and carb engines but they can be interchanged. I am not sure what year the air injection holes were put in the head, my 86 has them but I don't know if it is original. The mechanical fuel pump mount is cast on the 87-later blocks but the hole for the drive lever is not machined. It is easy to make the hole using a gasket for the pattern. The cam does have the fuel pump lobe.
Post Fiend
Joined: Jan 2000
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From: Dryden, ON, Canada
Intake compatibility
On the 87-91 trucks, the high pressure pump is on the frame rail, but, it also has in tank pumps, which makes things real easy, remove the high pressure pump and hook up a pressure regulator with a return line into the existing lines, and you're good to go.
The EFI and carby heads are not the same, but, when it comes to swapping manifolds, they are the same, with the EFI having a few more manifold bolts, bu, no change in the pattern.
You'll have to swap to a vacuum advance distributor also, as the TFI-IV system requires the computer, and most sensors functional to give you advance.
Evan
The EFI and carby heads are not the same, but, when it comes to swapping manifolds, they are the same, with the EFI having a few more manifold bolts, bu, no change in the pattern.
You'll have to swap to a vacuum advance distributor also, as the TFI-IV system requires the computer, and most sensors functional to give you advance.
Evan
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From: Memphis, TN
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Senior User
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Intake compatibility
Thanks steve83, but I've done that and got many codes. I investigated some of them and they are basically telling me that half of the sensors are not working properly. Also, the thermactor system is pretty messed up and I just want to un-clutter the engine.
PS - If I had the money I'd just throw a diesel in
PS - If I had the money I'd just throw a diesel in
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Joined: Jul 2003
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From: North of Toronto, Ontario
Intake compatibility
the manifold will work because i have done just the project that you have in mind. As mentioned above, the best way to manage your fuel delivery is to ad a fuel regulator to the existing line. When you change the manifold, there are air injection lines in the head that need to be plugged. You can cut off and plug up the individual lines, or leave the collector tube, and plug the large rubber hose that feeds them. The distributor swap is simply 1 out and 1 in. Now you have to get rid of that damn computer. Find a wiring harness off of an older carburated 6 engine. Plug one end into your new distributor and another end into an older style ignition modual. Feed the modual with 12 volts from the key ( your old coil wire will work fine ). The coil will have to be fed from the same wire, but you must install a resistor so as not to overheat the coil, or else buy an aftermarket coil designed to run on 12 full volts. Thats it Simple as it gets. Good luck.
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