So I have a N/A 1989/1990 RX7 GTU, I don't know whether to trust the title that says 1990 or the door jam sticker that says 1989, but that's beside the point. I keep reading articles that say the N/A FC RX7's have a 12 a and the turbo models have the 13b, however my intake manifold says 13b, was I scammed or am I just loosing my mind?

The reason Im asking is because every time I order parts, like a flywheel, it doesn't fit, even though the website claims it fits both the 1990 model of my car and the 1989 version, the bolt pattern I get on the flywheels I get are the 6 bolts or 8 bolts, none of them have the single 54mm nut with the drive spline that my car came with. Did anyone else have this issue?

 

Post a picture of what you have, specifically the transmission. Your title should match the VIN on the firewall, dashboard or door jam. It is very common for cars that are labeled as X year to actually be manufactured X-1. Go look at any dealership RIGHT NOW and you will find "2022" models for sale. The FC RX7 was never offered with a 12a from the factory, however if someone swapped it...it could fit. The FB had 12a and 13b options.

If you've ordered driveline parts here is why i've asked for pictures. The NA and T2 version of the FC had completely different drivelines from the flywheel back. The flywheel,clutch, starter,trans,driveshaft, differential and axles all must be either NA or T2. OR you have a compatible driveshaft to mate one half to the other. Regardless everything enclosed under the transmission must match. It also sounds like you purchased an aftermarket lightweight flywheel. the factory FW has a built in counterweight. All automatic cars came with one factory, and had a standard flexplate mounted to it. That is the way all aftermarket flywheels have gone. You will need to find a matching counterweight for your series engine (S4 or S5).

 

In the tenth position of your VIN, there should be a letter. The way FC VINs are structured, a K will be 1989 and an L will be 1990. And as you might expect, I have an M and have a 1991.

 

the door jamb sticker lists the date the car was built, which is in the CALENDAR year. the MODEL year of the car is in the vin number. the CALENDAR year and MODEL years are not the same, my favorite example is the 1993 Rx7, they were all built between October of 1991 and June of 1992, so none of the 1993 MODEL year Rx7's were actually built in the CALENDAR year of 1993.
the title will have the date the car was first sold, but that has nothing to do with when it was built, there is a 1995 Rx7 that got sold for the first time in 2004, so it would say 2004 on the title

the vin decodes thusly, if the vin is JM1FC3317L0800001
J = Country of Manufacture, Japan
M1 = Mazda
FC = The Chassis Code, Rx7's are FB,FC,FD. Miata NA/NB/NC/ND, etc etc
33 = Body Type, 33 is a coupe, 35 is a convertible.
1 = engine, 1 is the NA, 2 is a turbo
7 = Check Digit, this is a Federally mandated thing to stop fake vin numbers or something.
L = Model Year. K = 1989, L = 1990.
0 = the factory, all the Rx7's were built in 0, Hiroshima. 1 is Hofu, 5 was Flat Rock Michigan, etc
8 = i've been calling this the Version Number, it kind of acts like model year, but really it changes when the car changes. in a Japanese vin, FC3S-800001 it would be how you tell what version the car is.
00001 = Chassis number.

For North America:
the 1989 model year starts 12/24/1988 and goes to 6/30/1989
1990 goes from 6/30/1989 to 8/16/1990
1991 is 8/1/1990 to 5/27/1991