im swaping engines out of my 82 gsl and taking a 79 but the intake and exhust manifold ports are different.

would it be better if i rebuild my 82 12a or modify the 79 to fit.

thist is my first rx7 engine swap.

ok first off, you do not want to replace new tech with old tech, unless the old tech is better. In this case it isn't. The 79 motors are a pain in the a** to work with due to all the different exhaust recirculation ect. I did a 84 swap into my 79 and am happy with that. and besides you still can get factory parts for the motor (irons, rotor housing etc.) If you need to have the motor rebilut thats fine. DO IT. You will save a lot of heart ache and problems in the long run. IN FACT, what are you trying to do? Just a rebiuld, get it on the road and drive it, or are you after something else? If you want something more, look up my rebiuld under "the rebirth of my 78". MY personal suggestion after dealing with all this bs for nearly two years is this, call a engine biulder, a good one who uses non floor swept parts and have them biuld you a 12a w/ polished ports (no port timing changes but, better flow) and go one of two directions. One, get a weber ida 48 setup (~$700.00 outside of the motors cost) with a RB exhaust and cat (~$400.00)(for legality). or two do a fuel injection setup (~$1,800.00, if done right) the fuel injection will be a bit tuffer but when your done the car will have a little better fuel mileage, which with gas price going up to four buck a gallon is a big thing. NOW HERES THE BIG THING PAY ATTENTION, if you try to peice it together yourself you will get reamed $$ wise. If your going to eventually doing something like i was talking about, do it all at once, it will be much cheaper and you'll get more out of it. OH the guy who biult my motor was Rob "pineapple" golden. HE IS A AWESOME GUY AND KNOWS HIS SH**. He only biulds the good stuff, and the motors have a warranty. If you would like a quote for a full setup Call him at 1-503-233-3878 or go to his website http://www.pineappleracing.com. Hope this helps, cheers