Compatriots:

I have a 1990 F150 with 300 4.9L I6 engine (in wonderful shape) that has a mazda pos 5-speed bolted to it, which is now grinding when I have it in neutral. I would like to toss the mazda and get a nicer transmission, since it leaves much to be admired. Any suggestions? I would like something that gives me good towing capacity without driving my rpm sky-high.

I have heard good about the ZF-5, but am having trouble finding information concerning if the bell-housing bolt pattern is the same for the zf-5s that have been placed on diesel engines vs the 285/300/302 blocks. Any information you have on this would be great. The reason I ask about a diesel-mounted ZF-5 versus that which has been attached to a 300/302 block is that I have found a zf-5 which was on a diesel for $750.

Let me know what you think and what you know. I appreciate your help.

 

There are about three different configurations of the ZF. You will need a small block version for the 300 as the diesel and big block versions won't match. You didn't mention if it were two or four wheel drive truck (have to have a matching ZF), but with the two wheel drive trucks, you'll need a new driveshaft for the ZF. I think the length difference is less on four wheel drive trucks and you may be able to use the same one, but I do not know. My experience is with the two wheel drive version. Maybe this link will help: http://www.zf.com/na/content/media/i...ion_Charts.pdf

from this main site: ZF Friedrichshafen AG / Pickup Driveline

 

It is 2wd...

 

On a 4wd, you need 2 new driveshafts, not just 1... the difference is 3.5" longer rear shaft and 3.5" shorter front shaft. Not sure on the 2wd.
I would not buy the ZF unless you like winding your engine up a lot - the gears are widely spaced. Or, youcould get a diesel ZF and a gas Zf and swap the gears - diesel ZF's were made for lower revving motors.

Realize that the ZF is really a 4 speed, with a granny gear useless for normal driving. However, it has overdrive, so for "normal, around town driving, you have 3 gears to work with. I don't mind it with a 302 and 3.55 gears, but it might not work so well with a 300.

 

First off, welcome to FTE
second, look down in my post and view my classified ad, I have a 2wd ZF. Are you are close to ohio?

 

The 300 six should do just fine with the small block ZF and the stock gear ratios. Ford put the ZF behind the 300 from the factory, so I would think it works fine as-is. It can't be any worse than the transmission in my truck (no granny, geared like a five speed without third).