Well, I am pretty certain I will be pulling the fuel injected 302 in my 89 Ford econoline and replacing it with a carbed 300. The following is a list of everything I believe I need to do to swap a 302 out and replace it with a 300. I would really appreciate it if folks who know more about 300s than I do (all of you) could offer any tips, advice, or suggestions. Thanks in advance.

I have determined that a 300 block will bolt up to the AOD (non-electric) automatic transmission I have in the van now. I believe that 302 torque converter will still work, but I don't know what the stall speed is compared to the best converter for a six cylinder.

I will need to get a 300 from another van for the correct oil pan and oil pickup tube and motor mounts.

I will also need to get all the accessory brackets (p/s, A/C alternator etc...) from the 300 motor.

The EFI 300s have superior fast burn combustion chambers in the cylinder heads, but I will want to mill it to raise compression. I can use any 300 long-block.

I want to run an Offy dual-port intake with a Holley Economaster 4350 450CFM carb. This will require fabricating an adapter plate, but thats no problem. This will also require use of the exhaust manifold from a carbureted motor in order to keep carb heat.

I will need to get a Duraspark II non-efi ignition system including a distributor.

I will need to remove the electric fuel pump for the EFI currently on the van and replace it with a standard mechanical fuel pump. The highpressure EFI fuel pump is externally mounted on the left frame rail but there are low pressure pumps in the fuel tanks (I have dual tanks).

What is the best cam for low RPM torque and fuel mileage in the 1000-2500 RPM range? Should I leave the factory cam in there and be happy?

Anything else I have missed? I plan on freshening up the 300 while I have it out of the van (rebuild/mill head, check cylinder bores, new timing set and cam if necessary, new bearings if necessary). I also plan on recurving the distributor.

I have swapped motors in vans before and converted frmo 8s to sixes before (in Dodge vans) so I think I have hit on everything that needs to be changed, but I am still pretty new to Fords.

 

It's just nuts and bolts and some work...just like a Dodge. The 4360 is a good carb to run with the Offy DP and you can easily fabricate a plate with hose barbs installed for heat to the manifold and then you can use EFI exhaust manifolds. Any Spread Bore/Square Bore adapter will work to install the 4360. There is a "bump" cast into one side of the adapter that will hit the linkage under the choke housing but it can be ground off in a few minutes. To get the most from your intake upgrade have the manifolds/head port matched and do some mild porting in the head to improve flow. Check with the various cam suppliers and get their recommendations on which cam to use. Usually something up to the 260H advertised duration range is sufficient. The 4360 carb doesn't like cams with big overlaps so anything that keeps you out of the lumpy range should be fine. There may be clearance issues with the new intake/carb set up in a van to deal with. BTW the 4360 is a mechanical secondary carb and punching the throttle at low speeds may result in a hesitation and kick but if you educate your foot and allow the engine speed to pick up to about 2500 rpm plus before going WOT then it's usually not a problem.

 

Thanks. I am actually running a Holley 4350 Ecnomaster on my 84 E-150 but it has a 351W high output motor. It is a great little carb.

Thanks for the tip about the EFI exhaust manifolds. I will try and get a set of those and a carb heat plate to go with the dual-port.

Because the van has the AOD transmission the throttle and kickdown linkage is all cable actuated like a Lokar setup.

2500 RPM? With my gearing and OD tranny I only see that when I get to about 75 on the highway. Most of the time the 302 only sees 1000-1500 RPM. But I guess a 300 will have 3/4 the cylinders so the RPMs will increase.

I was doing some research over on Fordsix.com and got some good buildup parts lists.
I think I basically want to get an EFI motor, replace the intake with a Offy Dual port, mill the head, and swap the cam. That ought to get me where I need to go. I will get a y-pipe to tie the exhaust into the existing exhaust line for the 302. From there, it will just be a matter of plumbing the fuel and wiring up the ignition.

 

Whoops!...I was thinking manual transmission. The plate for water heat is easy to make...There is one commercially available that is made by a gentleman in Canada (Rasso Enterprises) but it is kinda spendy. When you take the stock manifolds apart, just use one side or the other to make a paper pattern and a 3/8-1/2 piece of aluminum works fine.

 

I thought Offy or Edelbrock sold carb base plate water jackets. Maybe Clifford.

 

You could also use a temperature controlled air cleaner housing (Thermactor?) that will keep incoming air temp above 70 deg. Electric fuel pumps for carbs can be used instead of the mechanical unit.
regards
rikard

 

There's no reason your RPMs would increase with an engine change unless you alter your gearing. If it has less power, it might have to downshift more to accellerate up to speed, but your RPMs in the same gear and at the same speed should be the same no matter the engine.

Hopefully when you do the swap you'll take pictures to keep us posted!

 

Thanks. As a side note, I took the van for a drive tonight and I saw that while doing 85 MPH the motor was turning 2000 RPM. The overdrive and rear gear ratio really keeps the motor spinning slow.

It might be awhile before I can get the time and parts gathered for the swap, but I will post pics as I go.

 

Sounds a LOT like my Bronco's 300. I have overdrive on my manual transmission and hit around 1700 RPMs at 75 mph. Not a lot of passing power, but I love the 18mpg. If I drop to 65mph at 1500RPMs, I get around 21mpg. Hopefully you'll net around the same with your new setup.

 

The van gets well over 20 MPG on the highway even loaded down with four adults, a wekend worth of luggage, and doing 60-75 MPH constantly. It gets high teens around town. I love the fuel efficiency, but it is just a tired motor. last night on hard acceleration it was blowing a huge cloud of smoke out the tailpipe. I think my rings are gone.

 

get the steel timing gear they are plastic from fomoco

 

That is great mpg with a van and a tired engine...kinda hate to mess with it?

 

True, but is it stalling out on me and pinging like crazy. Before I rip it apart I plan on doing a compression check, but my oil pressure is very low (30 PSI at 2000 RPM hot) and my engine vacuum is good at idle (17-20 inches) but as soon as I crack the throttle the vacuum drops almost to zero (I know some drop is normal, but this seems excessive).

If it turns out that the motor is in good shape but it needs some sensor or something else I won't mess with it, but if I end up having to pull the motor for a rebuild/replace I will probable just go to a 300.

 

just a thought...why not stick with an EFI 302? You KNOW that you won't be getting as good fuel mileage with a carb'd 300.

 

Well, I am getting almost as good fuel mileage with my carbed 351W (high teens low 20s) in my 84 Econoline, and I hope to match it when I install an AOD transmission. I figure with some careful tuning I should still get good mileage and have better power where I need it with a six cylinder rather than an 8.