While I very much respect
@Mark W as his acumen for such things goes much farther back than mine but I like experiments and this could be one of those silly more money or time than sense ones. And to
@Roastchestnuts : I hope you do not mind a thread hi-jack.
Back story - I received both of these engines from friends in trade. The 2F is an 87 from a US FJ60. It has a hole in the block (yeah I know - the head could be warped or cracked). It was a package deal with a car haul trailer. A sorta, "throw that pile of garbage in and you have deal." The 3FE is of unknown condition from a parts truck that was sitting at
@jynx place. Traded for a bare 80 front axle and an old Craftsman tool box I did not need. Oh, and a weekend of silliness.
The 2F has a hole in the block (I believe from oil starvation) but it sat outside and the rockers pretty toasted. I am almost embarrassed to post pics. The rocker shaft and rear most springs are a a rusty mess due to how it was laying in the yard. The cam and lifters are rusted in place. I had to beat the pistons out as they were also mostly rusted in place. Strangely, the carb seems ok, the thermostat housing is in very good shape and the intake, exhaust and EGR all seem good. I have stripped it completely and the block will either be yard art or go off to recycle. Probably the crank as well but I have not decided. The bearing spun on the bade cylinder. I have not measured it and I would not be surprised if it was worthless. The pistons and rods may become desk clocks.

As I was taking it apart and wondering why I was wasting another day, it occurred to me that even German tanks found sunken in swamps were occasionally restored and gotten to run.
The fuel injection on the 3FE is not complete and the wiring is all cut so I just do not think it is worth it to me to try to figure all that out. I have yet to pull the top or even the valve cover off the 3FE so maybe I am getting ahead of myself.
So that is a starting point to build a Franken-3F. I have never built an engine before and if I wreck this without it costing me too much other than time, well, you get the idea. (My mother, rest her soul, would say it keeps me off the streets, others might say my time is better spent elsewhere.)
Anyway, due to the water damage in the valvetrain attached to the 2F I went in to ToyoDiy.com to compare the part numbers of the stuff connected to the two different heads (2F v 3FE). Low and behold
almost everything transfers over.
The part number exceptions are: Exhaust valves, exhaust valve retainers, exhaust valve springs, rocker support studs on which the valve cover attaches, the pushrods and lifters. This means that all the damaged garbage on the 2F head can go to the scrap yard and be replaced with stuff from the 3FE head which is no doubt in better condition (all with the above exceptions.)
The question will be what lifters and pushrods I need to use? I assume the 3FE lifters as they are seated in that engine but I do not know what the difference is in the pushrods. The 2F ones were an absolute rusty mess.
Any insight on the differences between the 2F pushrod 13781-61010 and the 3FE pushrod 13781-61020? @cruisermatt maybe?
On a final note, I have like six ongoing projects so this will not be happening quickly. If you know any of the boys over at the STLCA they will tell you I work on my projects at the speed of smell.