I found a '74 13B engine from an RX4 complete with tranny , exhaust etc.

anyone know if the '74 Thermal Reactor will fit/work on my '79 ?

 

No the 13B block is wider than the 12A. why not run headers? or are you trying to smog it?

 

Thermal reactors... *shudder*

 

Yeah the 13B is longer so the ports are farther apart.

 

Are they further apart? I haven't looked at thermal reactors too closely, but the inlets on 12A and 13B exhaust manifolds are the same distance apart. I'm using a 12A exhaust manifold with slotted stud holes on my 13B right now. Either way, you'd have to add 10mm to the rest of the exhaust system for it to mate up.

 

That was what i was wondering . My current thermal reactor is in bad shape and I will likely go RB header , but I would like a stock setup to have anyway. Was hoping the RX4 stuff would match

 

Yes they are. Try matching a 12A exhaust manifold gasket to a 13B header or manifold, it doesn't line up. I got a 13B header last year by mistake when it was advertised as a 12A header and it was a no go on the 12A obviously unless you cut it

 

i would personally just get the correct thermal reactor for the engine you are trying to use. that or go with a racing beat exhaust. why are you replacing the thermal reactor on your 7?

 

Good-condition SA thermal reactors are getting a little hard to find.

Mine's a worst-case (Cali EGR 5-port TR) but it takes some sniffing around to find even a vanilla one that's not cracked, has the correct (uncracked) port inserts, and the all-important outlet ring insert.

If you don't need a TR for smog purposes, you're much better off running headers.