Hello!
Looking into learning how to swap a 350 small block chevy motor into my 84 fb rx7 gsl. Here are my main questions that I was trying to figure out before anything:
-Since grannysspeedshop has stopped production of mounting kits, does anyone know of a mounting kit for a 350 sbc? I've seen a few still available for fc's and fd's but not fb's.
-If there is no mounting kit currently available, does anyone know how I'd even begin mounting it? I've seen mounting plates before which looked like it might be an easier option, but I really have no idea. I can weld and am not too worried about fabricating something, but just don't know where to start on it.
-For anyone who's done this before, is there a way I can still use the stock drive shaft and rear end? Got a kiddo and don't have a huge amount of funds for this, so was hoping to keep as much stock as possible outside of a new motor, tranny, mounts, wiring, etc.
-Are there any other "gotcha's" when doing a sbc swap that I might need to consider?
Thank you for all the help!
Looking into learning how to swap a 350 small block chevy motor into my 84 fb rx7 gsl. Here are my main questions that I was trying to figure out before anything:
-Since grannysspeedshop has stopped production of mounting kits, does anyone know of a mounting kit for a 350 sbc? I've seen a few still available for fc's and fd's but not fb's.
-If there is no mounting kit currently available, does anyone know how I'd even begin mounting it? I've seen mounting plates before which looked like it might be an easier option, but I really have no idea. I can weld and am not too worried about fabricating something, but just don't know where to start on it.
-For anyone who's done this before, is there a way I can still use the stock drive shaft and rear end? Got a kiddo and don't have a huge amount of funds for this, so was hoping to keep as much stock as possible outside of a new motor, tranny, mounts, wiring, etc.
-Are there any other "gotcha's" when doing a sbc swap that I might need to consider?
Thank you for all the help!
Qingdao
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Mar 31, 2026
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No idea about kits, but your best bet is using the OEM subframe (crossmember or whatever you wanna call it) and make a second attachment a little further back on the "frame rails". But you might be able to just get by using the subframe alone.
A turbo rotary will tear the OE driveshaft and rear up. So I don't think the factory rear is gonna like the torque of a Chevy.
Pretty strait forward easy swap. Might need a shorter oil pan.
A turbo rotary will tear the OE driveshaft and rear up. So I don't think the factory rear is gonna like the torque of a Chevy.
Pretty strait forward easy swap. Might need a shorter oil pan.
Your RX-7 has a hood latch near where your sbc's distributor sits, that will limit how far back the sbc can sit. You want it as far back as possible. The large HEO style distributor caps with the ciol inside the cap will limit how far back the engine can sit, so the smaller dia distributor is preferred.
There is no factory oil pan for the sbc that will clear your RX-7's steering centerlink, so either the oil pan or the centerlink will need to be modified to clear one another.
Your sbc will need a short water pump if you want the radiator to fit vertically behind the core support.
When it comes time to mock the engine/trans in the bay, it's easier to do with the water pump removed. Without the water pump, you can stick a couple long bolts in the lower water pump holes, which can then sit on a 2x4 piece of wood long enough to sit on top of the car's sheetmetal "frame rails". This makes it easy to keep the engine level side/side with the car's chassis, just add equal amounts of shims to both ends of the 2x4 until the engine height is where you want it.
As for fabricating engine mounts, I would just make them solid. Make a couple plates that bolt to the sides of the engine, then also make a couple plates that bolt to the engine mount ears on the car's subframe. When you are satisfied the engine is where you want it, weld a piece of metal between the two plates. After the two plates are tacked together, you can remove them from the car and weld them up properly.
Your steering box will end up between cyls 5 and 7, so not many off the shelf headers will fit.
Stock driveshaft uses really small u-joints, also the length will not work. An '84 GSL should have a 4 pinion limited slip and the larger dia axles, it will be ok with a V8.
That should be enough to get you started...
Grant
There is no factory oil pan for the sbc that will clear your RX-7's steering centerlink, so either the oil pan or the centerlink will need to be modified to clear one another.
Your sbc will need a short water pump if you want the radiator to fit vertically behind the core support.
When it comes time to mock the engine/trans in the bay, it's easier to do with the water pump removed. Without the water pump, you can stick a couple long bolts in the lower water pump holes, which can then sit on a 2x4 piece of wood long enough to sit on top of the car's sheetmetal "frame rails". This makes it easy to keep the engine level side/side with the car's chassis, just add equal amounts of shims to both ends of the 2x4 until the engine height is where you want it.
As for fabricating engine mounts, I would just make them solid. Make a couple plates that bolt to the sides of the engine, then also make a couple plates that bolt to the engine mount ears on the car's subframe. When you are satisfied the engine is where you want it, weld a piece of metal between the two plates. After the two plates are tacked together, you can remove them from the car and weld them up properly.
Your steering box will end up between cyls 5 and 7, so not many off the shelf headers will fit.
Stock driveshaft uses really small u-joints, also the length will not work. An '84 GSL should have a 4 pinion limited slip and the larger dia axles, it will be ok with a V8.
That should be enough to get you started...
Grant