bugdewde

2 Newb questions...... seems I can't search this forum or google very well. Maybe I'm over-thinking it......

Is there a bolt-in crossmember/mount for putting this GM V8 T-5 into a NA Miata? I'd planned on just fabbing up a crossmember out of tubing.... but if there's one already out there...... ???? Apparently, my google skills suck...........

I have a NWC T-5 trans from a V8 Camaro with the 0.63 OD.
Torque isn't an issue with my intended tiny Buick 215 V8 swap that only puts out about 240-250 lb-ft of torque (old SAE rating ... probably much less by today's rating).
I plan on using the stock '94 Miata rearend/axles/hubs. (again, I'm only making about 240 lb-ft torque).

Really wanting to use the LT-1, T-56, six-speed since I'm using the 4.1 ratio Miata rear, but I don't want to do the major tunnel cutting that Flyin' Miata LS swap shows to fit the T-56. So if the T-5 fits without major cutting, it will get the nod. And I'll just have to live with the higher 2800 rpm cruising speed at 70 mph.

Also.... is there a specific hydraulic clutch (master & slave) that is preferred for the GM T-5 in an NA Miata ?

Sorry for the newbie questions, but it's past my bedtime already....... lol.... and I haven't found anything yet.

BGordon

Not sure there is a good definite answer to your question because it all ties back into engine & transmission placement.
You mentioned the Buick 215 which could throw a monkey wrench into the transmission placement due to oil pan and starter and exhaust manifold layouts. Without a mock up there is probably no way to get an absolute engine mounting location, which in turn defines the transmission mounting location.

As a starting point my guess is that you are wanting the shifter to stay in the stock location, presuming the things mentioned above allow for that placement.
If that presumption is correct, you might consider fabricating a mock up transmission crossmember by locating the transmission in your desired location and then fabricating a piece that would bolt to the transmission tunnel.
Take a look at this fabricators thread as he makes his own piece.
https://www.v8miata.net/general-moto...d-thread-2893/

Once that mount is mocked up you could do a trial fit using your engine and transmission to see if it will work or not.
Unless somebody else has done that particular swap, I believe that is your only practical way to see if everything will work.
If you mock it up and the factory front subframe appears to be a problem, V8 Roadsters makes their front tubular subframe without motor mounts for situations such as yours. It gives as much clearance for everything while keeping the correct suspension mounting points and steering rack location. As an added bonus it weighs quite a bit less than the factory stamped steel piece but is stronger and much easier to put engine mounts onto. In my opinion well worth spending the money even if you are pinching every penny.

On the hydraulic clutch hardware you can find several different ways to get there in the Ford V8 build threads as they commonly utilize the T5.
GM builds normally use the T56.
I believe I do still have the factory Camaro pieces laying around and you would be welcome to it if you want to try to make it work.

cvx_20

If you look at the areas where the tunnel is cut and enlarged, it is mainly to accommodate the bellhousing, not the trans. You can probably find an adapter plate for the early GM bellhousing to the T56. Or I know there is a Quicktime bellhousing that works well as an adapter for Fords, there probably is one for the Buick pattern as well. The transmission crossmember similar to the one sold by Martin and V8Roadsters is a good solution and is pretty simple to fab.

bugdewde

I like the idea of the upgraded subframe... that might be an option.

I'm not opposed to cutting the shifter hole, but moving the tunnel/firewall junction really isn't all that appealing (like in the Flyin' Miata instructions). When I do this swap in my Chevy Vegas, it only requires a little massaging with a hammer to fit. Cutting and welding and all that jazz isn't my thing.
Obviously, getting it further back would be best, but I'm not opposed to sticking those ears out past the firewall an inch or so if need be.... The 215 is quite light and I wouldn't think one inch forward would hurt much... unless I start getting into radiator issues.

Sadly, the 215 uses a specific Non-Chevy and Non-BOP bellhousing bolt pattern. It is unique an specific to only the 215. It has quite large "ears" protruding at 10 & 2 o'clock. However, the bellhousing appears to be a bit smaller than the traditional chevy or BOP bell. (215 on left, 64-later Buick on right)

bugdewde

It seems the only 215 swap I found with build pics show a Ford T-5 trans without the bellhousing. It appears he also cut the tunnel and widened it. Dang.... really didn't want to do all that. Guess I'll have to hire that out.

BGordon

There is one kit that fits the GM V8 and T56 into an NA Miata without cutting the transmission tunnel.
It locates the engine away from the firewall.
Perhaps since you are doing custom mounts this would work for your swap.
You might check out an ongoing series of YouTube video's being done by a guy named
Taylor Ray.

If nothing else it might give you an idea or two and point you in a workable direction.

Sorry that I can't be any direct help as your swap is interesting and very close to the original concept that Carrol Shelby did when installing small block Ford engines into the Sunbeam cars.

cvx_20

You might try the "other" forum at miata.net. Do an advanced search for "rover" in the engine conversions subforum. Also, you might look into the T5 used on the earlier Camaro V6. It might have the wide bolt pattern to fit your bellhousing. Also, the kit used by Taylor Ray came from Martin at Monster Miata, the guy who has been responsible for many, many Ford conversions. He now has a new subframe designed for the LS motor that mounts the engine somewhat forward, minimizing the cutting at the firewall. Probably worth a phone call: http://miataroadster.com/monster-mia...s/g-67757.aspx