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when I first picked up this engine I pegged it as a stock s1 12a. however when I got all the manifolds off and saw the long primaries with the air pump port it threw me off, specially when I went to mazdatrix to try and match it to an intake gasket. so what is it? is this an untouched engine, or one that someone opened up the primaries on an s3 engine? its not a huge deal as I have an extra s3 center iron, just wondering exactly what this is, as I had never seen it before. also if anyone has suggestions on what to do with it I appreciate any comments (I.E. use this center with s3 intake, replace it with the s3 iron ect....). I may be getting an RB side draft intake, so if that has any sway as to what I should do those suggestions help as well https://www.nopistons.com/forums/pub...IR#>/smile.gif thanks in advance!

is that a semi pport? j9 can probly help

no, those are coolant passages for the stock intake https://www.nopistons.com/forums/pub...IR#>/smile.gif

Unless it has 2 dizzys the motor belongs to the 78-80 series 1 rx-7 (I say 78 because the car was distributed on may 78 as the 79 model) I had the same motor in mine before I replaced it https://www.nopistons.com/forums/pub...R#>/tongue.gif



cheers

more pics would be good, but it looks like 79-80 rotor housings and 81-85 irons?

nope, one dizzy.





thats what I am thinking too, but why open up the primary ports like that, when it had the small primary intake on it to match the air pump port? any real advantage to it? and do y'all think the RB intake will take advantage of those bigger primaries or should I just put a stock center iron in?



I'll try to have more pics by tonight, I had just snapped these quick to get some answers https://www.nopistons.com/forums/pub...IR#>/smile.gif

the 81-85 center housings are like that stock

really? then maybe I don't have an '85 center. the center I have came off of the engine that was in my '85 and it matches the 81-85 gasket at mazdatrix



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verses the 76-80 gasket, which more accurately matches the ports on the engine in question, minus the air pump port of course



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so, will the stock '85 intake (which matches the 81-85 gasket) take any advantage of using the center with longer ports or not? I know its kinda a dumb question, but I'd hate to build it one way only to tear it apart again to make a better combo later (specially since I AM going to be getting the side draft fairly soon)

the later centers dont match the gasket. the intake does.

ah I see. so I know the engine I pulled out was rebuilt. could it have been built using a 13b center?