'72. Engine swap F to 2F Help (1 Viewer)

6h9

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Sep 19, 2018
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I need some help on this. I have a '72 F engine. Recently the rod bearing spun on the crank. Good news it didn't blow a hole through the oil pan or destroy the cylinder. Bad news it is a costly repair to do it right.

Im thinking of finding another F engine. Possibly a 2F. From what I gather, it should be a easy swap. Im not sure about the transmission. Should I keep the 3 speed or find the 4 speed that would go with a 2F. Does that change the transfer case, drive shafts, etc. Or is it a pretty easy swap out and in?

If I stuck with the 3 speed, can that be mounted to the 2F? Im ok with the 3 speed unless at 55mph #4 gear allows me to cruise a lower rpm.

Not sure. Im still in shock about the engine. It is a pretty sad day since the girl when down.

thanks for your help!
 

Xpnsv72fj

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Hanover VA
I as well as many others have this exact swap.

My setup is a 72
86 2F
4speed

The 2F with swap in easy, you can use either a 4 speed or 3 speed trans. If you stick with the 3 speed you will need to use the 3 speed bell housing which will bolt up the 2F. The gearing is the same so going to a 4 speed isn’t gong to help you go any faster.

Josh
 

6h9

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Sep 19, 2018
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Thanks for that. If going to a 4 speed isn’t going to get me a little faster on the highway, I may as well stay with the 3 speed. Sounds like the motors are a easy swap.
 

Jdc1

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You’ll want to run the F intake and carb on the 2F. 2F intake won’t clear the brake booster and having to retrofit the steering linkage is a PITA.

Another option might be using the Holley sniper fuel injection and 2F intake to clear brake master but I’m thinking out loud and haven’t gotten to play with it.

4 speed is a lot more driver friendly as 1st is synchroed. Just use all of either the 3 or 4 speed clutch plus 4 speed bellhousing and tranny/trans.
 

4Cruisers

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4 speed is a lot more driver friendly as 1st is synchroed. Just use all of either the 3 or 4 speed clutch and flywheel plus 4 speed bellhousing and tranny/trans.
All clutch components for either a 3-speed or a 4-speed (flywheel, throwout bearing/hub, clutch fork/retainer clips/pivot stud, and pressure plate). The clutch disc is the same for the 3-speed and 4-speed. All parts for the 3-speed clutch components can fit the 4-speed bellhousing. When I installed an H41 4-speed with 3-speed transfer case in my '76 FJ40 I used the 3-speed flywheel and clutch components. The extra mass of the 3-speed flywheel helps keep things spinning when shifting gears at lower rpms.
 

6h9

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Sep 19, 2018
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PA
I did hear that the benefits of the F is the height of the flywheel. If I can put that on the 4 speed that would be awesome. I did recently have my flywheel surfaced and new clutch accessories are installed. I would hate to lose all that work I have done already.
Same thing with the manifolds. I had them reground so they are flat. Also I have a Holly carb that was working great. If that can get swapped , it would make me happy.

By the way, when I bought my fj, it came with two original carbs. If anyone is interested. For that matter. I have a number of parts I haven’t listed that are sitting in my attic since my restoration. Tie rods, bench seats, glass, body parts that can be used for patching, e brake slide. Let me know if you need something.

Thanks again for your comments. It has been very helpful. I appreciate the help!
 
Joined
Jun 7, 2011
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413
Location
East TN
My March 1972 FJ40 has a 4 speed out of a 1978 matched to the transfer case out of the '72 and the disk brake front axle, also from the '78.
The 2F engine should swap in for the 1F however going to the 4 speed is a BIG project.

The center cross member on your 1972 frame is too far forward to accept the longer 4 speed transmission.
I believe it may just fit if the engine + transmission + transfer case is installed as a unit with the parking brake assembly already on the transfer case but there will only be about 1/2" of clearance to the cross member.
You will not be able to remove the parking brake assembly with the transmission installed.

The common fix is to cut and re-weld the cross member further back or to rotate it and re-weld it so the arch clears the brake drum.
I cut out the cross member and welded flanges on the ends so it bolts to the frame further rearward.
At the time the body was off of the frame.
It would be a nasty task to do it all from under the truck.

Since the 4 speed is longer, your current drive shafts will be the wrong length... Rear must be shorter, front must be longer.
The drive shaft flanges are different on the later models for the 4 speed trans. bolt holes won't match.
Your earlier transfer case won't fit the 4 speed transmission unless you buy an adapter kit to swap out the gear that goes on the transmission output shaft.
Depending on what combination you end up with you will probably need to adapt the ends of the drive shafts.

I think that some of your accessories from your 1F may not fit on the 2F.
If you just get the long block for the 2F for example, your 1F manifolds may not fit.
The alternator may also be different.
I have a complete 2F for my 72 to replace the F someday so have all parts for both setups but haven't gotten into it yet.

I see two 1F motors for sale today south of Knoxville TN, one "rebuilt" and one not.
Check Knoxville Craigslist.

Good luck.
 

6h9

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Sep 19, 2018
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PA
thanks. that is helpful. I located a 2F with 50k on it. he has the 4 speed, transfer, and drive shafts. Im not sure if those shafts will work or not. length wise.
 

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