these are both suppose to be fd twin...why does one have 3 dp studs and the other has 4 dp studs?

 

I've never seen that kind of casting on the turbine housing flange before?? Maybe it's from a Cosmo?

 

cosmo twins are streched out more becuase of the 3rd port, these twins only have two ports.....i really dont think thier fd twins...

 

mine are like that, all two of them

 

the ones with 3 studs are cosmo RE twins, hitachi ht-10s I think, the ones with 4 studs are REW twins, hitachi ht-12's I think. You'll find that the cosmo manifold is also a bit different, plus the plumbing is too. They are not a direct swap, and the cosmo turbos are inferior to the rew's. Spool time would be reduced but so would top end...that engine was made for max low end torque to pull the heavy cosmo chassis around in automatic form while the REW was more suitable to a lightweight sportscar with a nice top end.

 

thanks for clairifying that...i forgot some cosmos have 13b-re's

 

and i always thought the 13b-RE's were singles.....D'OH