Tree25is

what year car do these SOB's come in?

1984se

early truck motors and TII...why??? Need one? I got one for sale and you could also use SE housings and 12 end plates and come out 4 port.

-Ryan

Metallic_rock

any turbo 7

my car

Rx4, Repu, Old Cosmo?

or you can make one from a 13b and 12a end plates.

Siraniko

iTrader: (13)

NOt quite..
old 4 port 13-B = RX-4, RX-5 Cosmo, REPU.

Now for the GSL-SE, use the 12-A intermediate and side plates and you will end up with a 4port 13-B.

TII and TT are 4ports

1984se

hey we posted at the same time! ! !

Siraniko

iTrader: (13)

1984se

u postwhore...

Siraniko

iTrader: (13)

Wankelguy

The '74-'75 4-port 13B motors had the largest stock ports of the old-school 13Bs. In 1976 the ports were restricted as a response to the fabled "energy crisis" of the '70s. Also, 4-port 13b motors were produced for the Japanese market much later. These motors have fairly restrictive intake porting, the primaries being the most affected. The Japan-port motors have the added advantage of using newer-style gas-nitrided side and center housings, which are actually easier to port as the metal is softer once the gas-nitrided layer is passed.

Jeff20B

iTrader: (13)

The R5 13B I mention sometimes has four ports and nitriding with rotor housings that were meant for cats. No US spec car ever had an engine like this.

Siraniko

iTrader: (13)

If that is true, why are the intake ports on a 76 RX-4 and RX-5 Cosmo’s are taller than the 74’s.

Jeff20B

iTrader: (13)

Intermediate ports are. The end plate ports are the same height. For what reason? Hmm I know the Cosmo had a reversed runner intake manifold where the primaries had long runners into the end plates, and the secondaries had short runners into the intermediate plate. Maybe this was part of Mazda's AP (anti pollution) program in '76?

Siraniko

iTrader: (13)

i have several 13-B intake manifolds (74 - 76) at home. I will take pix