xlemon15x

Hello everyone! This is my first post on the forum, and so far, it been a great resource in my Miata adventure. I'm planning to put a Ford 427 FE in my NA Miata this upcoming year, and was wondering if anyone has ever done this swap? I know that the 427 is a heavy motor and will make the Miata handle worse, but I want to do it because the 427 has been an engine I've been infatuated with ever since the Cobras and GT40. I have no idea where to start on this kind of project (I don't even know if the motor will fit in the car hence why I'm wondering if anyone has done this swap). I have done a K20 swap in a Civic hatch before, so I familiar with doing a swap myself, but this will be the first time I ever do a fully custom swap without any kits or such. Any help would be greatly appreciated! Thank you!

mrmustang

Having built numerous small block V8 miatas, as well as small block and big block Cobra replicas, I can tell you the biggest issue will be clearances. Clearances for the custom oil pan, and clearance for the type of intake and carb you plan to use. Low rise intake will be a must, the rest, potentially doable, but not quite as streetable as you might think.

Look forward to watching you accomplish your dream

Bill S.

engineer

Hi,

I am with you on the love of cobras and the 427 idea. Its a great thing to have large engine in a small car...hence why we are all here

But the reality of doing it will likely bring its challenges.

I think it "could" fit, but you will run into hood clearance issues without a hood scoop. Also the subframe will need to be a custom unit, exhaust will need to be custom. Steering shaft clearance will be tighter, firewall clearances, radiator clearances, overheating issues (just like the old 427 cobras) , etc.

If you eventually get it all to fit, the other challenge will be to make it work dynamically. Having too much torque too quickly, will make the car break traction a lot easier. This may sound like fun but can become tiresome if the car cant accelerate cleanly, or simply taking off from traffic lights in the wet. All the extra torque and power is lost to wheelspin...and cant be used.

For these Miata cars I would advise that a higher revving, higher power engine is more favourable in contrast to a heavy, torquey lower revving engine. By bringing torque in later the car has more time to get its traction down.

A small block option 8.2 in deck block can go to 372 ci (dart block) and can (with the right combination of parts) make up to 550hp..this is big block power territory in a package that will fit relatively easily. There is a lot of merit in having a high revving (7000rpm) 331/347/363 engine in the car.

I would be inclined to go down the small block 8.2 deck road (there are many options for config like 289, 302, 331, 347, 363, 372) as the 427FE road is going to be a headache and for little to no gain in actuality.

I know this is an old thread, but i am bored at work today

Cheers,

JimD

I would think that if you really loved the look of a BB-FE motor in a car like the MIata, then maybe you might entertain the idea of a sort of fake 427FE. What I mean is a smaller engine (like a 351 that can be taken out to 427 cubes), or a
302/331/347, ect. with the FE valve cover adapters for a small block. With cams, intake and large exhaust, it can sound and look like a big block FE! Just for fun anyway-right?