Which chassis to go with?

[Rennkafer]

Miata engines are definitely marked, big VIN tag on the right side of the oil pan.

13B's depending on the year may just be old enough they didn't.

[JAMADOR]

Miata engines are definitely marked, big VIN tag on the right side of the oil pan.

13B's depending on the year may just be old enough they didn't.

My current [non-running] engine doesn't have an oil pan, either.

[tibimakai]

I should probably buy these components from a car part reseller from Ebay or similar, right? This way I have some proof.

[JAMADOR]

Depending on the state, a bill of sale may be sufficient.
In TX, I believe a BOS is all that's needed for non-chassis components.

[Miatav8,MstrASE,A&P,F]

The VIN rules have changed about five times over the years. Used to be FMVSS 115 but is now part of 49cfr 565. The first rule is in 32 FR 20833 (Dec ’67).

Production numbers on the drivetrain are not required to be the vin. I think it is more for traceability than anything. The required vin is anti-tamper and required to be easily visible.

The production numbers (that range from barely associated to the vin to being the actual vin) are convenient for reporting theft if they are known. The inspection process may require access to see the numbers for a theft check.

The donor drivetrain numbers are not subject to a test for matching to a vin. Typically, with “partial vins” only the mfg knows if a particular drivetrain production number was installed in a particular vin vehicle.

The donor vehicle VIN would not necessarily be salvage. People sell the entire drivetrain out of cars for all sorts of conversions.

[tibimakai]

Back again. Last week I have purchased the metal!!
I'm in the middle of a purchase, of a 5 speed 1990 Miata trans.
I'm not sure which bill of sale should I use, the one from the DMV for cars, or just a form made by us?
Any speedy reply would be appreciated.

[Bent Wrench]

You don't need an official form, a bar napkin becomes official when you sign it.

You just need a receipt, for a used trans.

DMV will likely assign a VIN.

[tibimakai]

Found a basic form online and we used that one.
There is a vin plate on the trans and it seems like it matches with the car's vin#.
Now I need to find out, if it any good. It looks clean and dry. The owner claimed that it only has 55k on it.
They have replaced it by mistake, it ended up been the diff that was making the noise. They had this trans in storage for a couple of years.
How could I test it out, if I have got a good trans or a bad one?
I see, that it still has the old "bad" neutral switch on it, that most likely I will have to replace.
It wasn't a planned purchase, it just showed up on CL. These parts are getting harder to find, so I have jumped on it.
Now I'm starting to learn about it.
I think that I will go with a Ford 2.5L engine, they are plentiful and they are cheap.
Thank you for the help.
I'm still not decided about the chassis. I'm between the 442E and Vodou.

[Rennkafer]

Be aware that the early Miata 5 speeds (in the 1.6l cars) are weaker than the later ones. A 1990 gearbox may not be the best answer behind a 2.5l engine depending on how much torque you plan to make.

[tibimakai]

A Youtuber said, that it could take max. 240 tq?! If that is true, I'm OK with that.

[Rennkafer]

A Youtuber said, that it could take max. 240 tq?! If that is true, I'm OK with that.

Maybe a later 5 speed would put up with 240wtq, but only if driven pretty mildly. I wouldn't expect an early box to last long at that power level. Keep in mind the 1.6 Miata only put out 100ft-lb of torque.

[tibimakai]

Then, I guess I will stick with the stock 2.5L for a while, until I will upgrade the trans and engine.
Thanks for the heads up.
Anything that I should know about the 2.5L engine, before I buy one?
Do you know anything about the balance shaft(the one that is inside the oil pan), should I keep it, or remove it?

[tibimakai]

The NA transmission even bolts up to the Ford 2.5L engine?
Do you guys recommend the NA(1990) open differential for my setup, or should I go for a later one?
It matters if it is manual, or automatic the car?

[Rennkafer]

The NA transmission even bolts up to the Ford 2.5L engine?
Do you guys recommend the NA(1990) open differential for my setup, or should I go for a later one?
It matters if it is manual, or automatic the car?

I don't believe that the NA trans does bolt up, the NC used the MZR/Duratec

You definitely do NOT want a 1990 differential. The 1.6 diffs are well known for breaking at low power levels, the later 1.8 has a larger ring gear and is MUCH stronger. My personal favorite would be a 94-95 1.8 Torsen. 94-95 had the Torsen Type 1, 96-97 had the Type 2 Torsen, and NB's ended up with a couple different limited slips used. I like the 94-95 because IMO the Type 1 was the better differential, and it has external 4 bolt flanges for the halfshafts. The later cars all have splined plug in halfshafts. 1.6 diffs also have 4 bolt flanges, so don't be fooled into thinking it's a 94-95 by that alone.

[tibimakai]

Thanks for that.
Unfortunately, the Torsen ones are expensive, at least $800. I don't think that I really need it for street use, right?