I6 300 to M5r2 trans. Which flywheel?

Hi folks, not been on here for awhile.
I was going to fit a T5 manual trans to my 1980 F100 I6 300 2wd in place of the T18. So I sourced a zero balance 157t flywheel to use for the conversion instead of the 164t flywheel which I believe wont fit in the T5 bellhousing. However, I now have the option of using a M5R2 trans instead.
Would the 164t flywheel currently fitted to the engine fit straight in the M5R2 or would I still need to use the 157t flywheel?
Also, would the current starter also transfer over on to the M5R2 without any issues?
Many thanks for any help
Alan

Blacktop wrote

Would the 164t flywheel currently fitted to the engine fit straight in the M5R2?

 
Yes.

Blacktop wrote

or would I still need to use the 157t flywheel?

The 157 tooth flywheel will not work with the M5R2.

Blacktop wrote

Also, would the current starter also transfer over on to the M5R2 without any issues?

Yes.

For a 2wd, you'll want a 1988-1991 M5R2 if you can find one. The 1992-1996 M5R2 will fit and work just fine, but 1991 was the last year for the cable driven speedometer.

Many thanks Rembrant, yes the M5R2 is from an '88 F250 2wd.
E8TA-YE trans id.
So its a straight forward trans swap then, except to convert for the hydraulic clutch etc

Alan

Blacktop wrote

Many thanks Rembrant, yes the M5R2 is from an '88 F250 2wd.
E8TA-YE trans id.
So its a straight forward trans swap then, except to convert for the hydraulic clutch etc

Alan

Cool! When I did my first M5R2 swap, my trans also came out of a 2wd F250, but a 1991. The ID on mine was F1TA-HB, so the same as yours, with the same speedo drive gear.



Luckily when I did mine, my 1984 F150 already had a 3.08 differential, so my speedometer even stayed correct after the swap.

I later did an M5R2 swap...sort of...I put a 1980 body on a 1995 chassis with an M5R2, so I went through the process of adding the hydraulic master cylinder, etc.

Oh...swap in an 11" clutch when you do the 5spd swap also. That is what came with the 5spds. Your stock clutch is probably a 10"? The flywheel should be drilled for both...at least my factory flywheel was in 1984. The 10" should work fine, but if you're swapping the clutch anyway, why not?

Good tip on the 11 inch clutch👍
Did the conversion for the hydraulic clutch on the 1980 body go easily?
I made a template from my 1984 truck that I intend to use to drill the mounting holes on the 1980 truck firewall. I will add some strengthening at the same time to stop it flexing.
Alan

Blacktop wrote

Good tip on the 11 inch clutch👍
Did the conversion for the hydraulic clutch on the 1980 body go easily?
I made a template from my 1984 truck that I intend to use to drill the mounting holes on the 1980 truck firewall. I will add some strengthening at the same time to stop it flexing.
Alan

Yes, it was pretty straight forward. Like you, I had my 1984 with factory hydraulic clutch at the same time so I had it close by to measure and copy. There's not much room for that master cylinder...it's almost hard against the brake booster, so the side to side measurement is almost a no-brainer. The vertical position is all you really need to study. I bought a hole saw the same size as the master cylinder housing...I think around 1.25" or something like that. It was readily available.

On both trucks with the M5R2 swaps, I ordered new clutch slave cylinders and hydraulic lines for a 1991 F150, and used clutch master cylinders from 1984. The 1984-1986 master cylinder is the same as the 1987-up ones, but the studs are in different positions. Otherwise they are identical.




Good idea to brace the firewall for the clutch master. For my 1984 I installed a brace from Terrapin, but they are no longer making them. I believe JBG is the only company offering them currently. For the 1980 swap, I just made a little brace myself and it worked fine.

I bought new seal kits for both M5R2's...they were cheap-ish and easy to install. They're known for leaking at the rubber plugs on the top cover. I replaced them with the little metal plugs, but I later had an issue with trans fluid coming out of the speedometer cable in the dash LOL. The shifter bushing kits made a BIG difference as well.

PS: You can buy new plug/pigtails for the M5R2 reverse switch FYI. They're cheap if you need one.

Did you get the correct crossmember to go with the M5R2 as well?

I'm a big fan of this transmission and swapping it into Bullnoses. I had great luck with mine. The first one was quite "notchy" shifting 1-2-3, but it got noticeably better as it warmed up. It was used after all, with probably 100,000 miles on it...so I can't complain. That's only what the guy told me...it could have had 300,000 miles on it for all that I know.

Another thing I did was I welded an NP435 4spd shifter stick on to an old M5R2 shifter stub I had. It wasn't that I was crazy about keeping the truck period correct lol, it was just something to do.

Wow, thank you for all the info Rembrant👍
I didnt get the crossmember unfortunately. I'm hoping to use the existing one and just reposition it if needed🤞
I bought a new clutch master cylinder but will also get a new slave and pipe to suit the M5R2 aswell. Also will buy the shifter bushing repair kit and propshaft seal just incase.

Alan.