we are goin to swap a 86 13b into a 85 rx7 that had a 12a 6port in it has anyone tried to use the ignition off the 13b on the swap plus what rb exhaust sytem should we use going with the webber carb set up any help would be grateful thank you

 

You'll need to run the stock ECU from the 86 to control timing, as the FC's get their signal from the CAS whereas the FB's get their signal from a distributor. In all honesty it would be much easier and way less wiring to use the FB ignition system again.

For the exhaust it'll be a hot debate, whether to run long primaries and do a true-dual exhaust system (one pipe for each rotor housing) back from the header to a collector at the muffler or just run a single-back pipe from a collector right at the header. 2-1/2" pipe is all you'll need, and even that is probably over-sized for your application.

 

ok i was thinkin of doin a dlidfis sytem with the stock 13b ignitors and coil packs with a dizzy out of the 12a

 

Replied in your other thread: https://www.rx7club.com/1st-generati...-pack-1136695/

For your exhaust you really want to the true dual full exhaust of the RB SP system. Get the whole package, its a bolt on an will last longer than the car. It will help make that weber sing.