I have a 81 ford with standard clutch a 400 engine. I am looking at a 5 speed transmission with a low first. It came out of a 1990 bronco with a 302. I haven't been able to see it yet. I just wondered if someone could tell me if it might work and would I have to switch to a hydraulic clutch. Thanks.

 

I also have an 81 with the 400 engine, I have the T18 (granny-low) 4 speed transmission, 4WD and 4.10 axles.

I understand the best we can do is get a ZF 5-speed transmission (I forget what years & models have the variants that will fit onto a 400's bell housing bolt pattern (the ZF 5-speed has the bell housing built into it)) but it'll require converting to a hydraulic clutch.

Do your research here, I think the only other 5-speed transmissions offered were those made by Mazda, something like an M50D or some such. I don't recall if that has a bell housing built into it or not.

 

The 351M and 400 engines share the bell housing pattern with the 385-series engine, which includes the 460.

I wanna say something like an early 90s F250 with a 460 would be a good donor vehicle for doing a ZF swap but, remember, need a hydraulic clutch (which involves fab work and possibly (probably) pedal assembly replacement).

 

All the 5 speeds that Ford used in their trucks and Broncos had a integral bellhousing. And since Ford decided to use a different bell pattern on almost every engine they built(not really but it seems like it), you only have certain choices for a 5 speed that will work. The 460 zf is your only choice. And yes, you will have to convert to a hydraulic clutch. That's not as hard as it sounds if you can find a 86-down truck that had a hydraulic clutch setup already and rob it.

 

I just swapped a Mazda 5speed into an '83 w/a 300 six. Although I can't speak to the Z-5 swap, I can tell you about the hydraulic clutch needs.
You will need to reinforce the firewall or it will crack under the pressure exerted on the clutch Master Cylinder. I do not know when they started putting the small reinforcement plate on the firewall but I know it is on the '94's, I used it in my install.

I was lucky in that the '83 has a large reinforcing plate already installed on the firewall in the engine bay that had the cutouts for the MCyl already there. All I had to do was drill through the firewall sheet metal where the cutouts showed & trim some ribbing to fit the MCyl. My understanding is that was the first year that occurred so you will need to take measurements from an existing hydraulic clutch installation, or at least an '83 with the cutout plate.

Before you do that, figure out how you want to set up the pedals. You have a few options, I chose the cheap way out but it is not the only way. My results are why I caution you to check measurements on the MCyl placement before you cut, let me explain.

According to others on the board, you can bolt in an '86 or older pedal assy. I was pressed for time so went the following route.

I used the existing pedal assy. in the '83 (my donor was a '94 & would not be an easy swap). But since the '83 mechanical clutch went down through the floor, the actuating lever geometry was wrong & I could not get sufficient throw to depress the MCyl completely. I tried swapping the pedal assy. from the '94 which did not work, tried swapping the pedal shaft assy. which was too short, and finally settled on swapping just the lever. The problem is that the lever attachment is totally different between the '83 & '94. I ended up cutting out the '94 lever to fit the '83 shaft w/a Dremel & a file. It worked (see post page https://www.ford-trucks.com/forums/1...roblem-7.html? for some explanations & pics).

Anyway, the reason I caution you on the measurements is the MCyl mounting MIGHT be different depending on the year. I actually tend to doubt this but just throw it out there as a possibility because of the different lever offset between the '83 & '94. It might be explained by the shorter pedal shaft but "measure twice - cut once" is not a bad mantra to repeat.

Hope this helps...

1999 E320 (mine but daughter has it)
1994 F150 #1 (hurt) 1994 F150 #2 (parts)
1989 560 SL (wife's DD)
1994 945T (daughter's but I have it) 1986 242Ti (fallow)
1968 GT500KR (under restoration)
1941 Luxury Liner (son's project)

 

Also be aware of the difference in the transmission input shaft splines. You will likely need a new clutch and the flywheel properly drilled for it.

If you have 4wd make sure you get a 4wd transmission and vice versa.

Since the ZF/460 combo was most likely in a '88 and up 250/350 you might have to mod the driveshaft(s) in your F100 or use offset universal joints.