F 1.5 Engine and T-case....

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Oct 9, 2008
Lake Arrowhead, CA (was), Rocky Top, TN (is)
So I have a July 1974 FJ55 in my back yard that has been screaming for attention and, honestly, I just don't have the time to devote to her.

Reluctantly, I have put her in the 55 series classifieds and am trying to sell her as a whole rig for $1000, but may have to part her out if no one bites.

Through my readings here, I've learned that this truck has a pretty coveted engine - the F 1.5 (2F oiling system, but F engine configuration and flywheel for more torque). Am I understanding this correctly?

Also, it has the 4 speed and, therefore, has the transitional transfer case (again, correct me if I'm wrong).

I've also read that these '74 blocks are uber-hard and last just about forever. It seems, too, that the head can be put on a 2f block for higher compressions....

With all that said, would it be a good idea for me to keep the engine and t-case for future projects (if I end-up parting her out)? Are there other pros and cons that I should be aware of? Whatever you can share is much appreciated, as always.....
I would spend the money on a 2F long before I thought about building an F engine. The F and a half is a novelty of the pre 2F engine series.


As far as the more torque idea, the 2F made better power numbers than an F, and the <10 lbs difference in flywheels between the F and 2F does not, and would not ever equate to more torque output, as it does nothing to generate power. Having pounded a 1982 2F since 1995, first with an F flywheel and for the last four years with a 2F flywheel, I have not been able to discern a difference large enough worth fretting over installing an early flywheel over the later style.

Poser - Thanks for your experienced reply on this one. Is there something about putting a F 1.5 head on a 2F engine that makes it worth doing (something about higher compression)? :meh:

Also, what about the t-case - is the transitional shaft worth holding on to? I just don't want to part out a truck and then do a :bang: when I realize I sold something that I could've used or that would have been an improvement for my "keeper" rig.

Thanks again for your input - I really enjoy learning about this stuff....:D
I had that same drivetrain in my 12/'74 Pig...ran it for years, even rebuilt it once.
Moved on to a 2F block with that late F head. Works fine but it's still a dog on the hills.
Also did the 3-speed gears into the Transition Tcase mod...it's a cheap and easy mod but only gives about a 5% increase in crawl ratio.
Those parts may be of interest to somebody, but I don't go :bang: for going with the 2F/465/doubler in my "keeper" rig....
do you think it would be worth putting the late F head on my 3/79 2F block (in my 40) - or not worth the effort?

Well, if your doing an engine build it might be one of the things you could do, but a head swap all by itself probably wouldn't give you any seat of the pants improvement...
So Pighead, Poser, whoever, I need a quick opinion from you: I have a 1974 F.5 engine that I had the head completely rebuilt on less than 500 miles ago.

Today, I dropped off my 2F at the machine shop to begin the complete rebuild, including rebuilding the 2F head. So the question is: I can save money by using the F.5 head instead of paying and rebuilding the 2F head. Is there any other performance benefit such as higher compression, etc? Is re-using the F.5 head the recommended route or should I just keep it as a spare and go ahead with getting the 2F head rebuilt? Let me know so I can call the shop tomorrow and have them hold off on the 2F head if that is what you recommend. Thanks
That's a hard question...it might depend on what else you are doing to the engine.
Higher compression is why I did it.
I am just rebuilding it, .40 over on the bore and putting in a MAF RV cam kit. I would like to raise the compression a little bit. Am I better off having the machine shop shave the 2F head and go ahead and rebuild it, or would you just use the already rebuilt F.5 head? If I use the F.5 head, how much of an increase in compression can I expect?

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