4.6 V8 Engine swap - 1966

I'm thinking of swapping out the 390 and trans. for a '96 4.6 liter and trans. Has anyone tried this and if yes, what were the biggest hurdles and hoops?

Howard Helser


Active Member
Is this because you have oen of those little suckers lying around? Not sure if putting a small block (and a small 281 ci small block to boot) with those oversized heads and tiny 3.55" pistons in a Bird is great idea. Plenty have talked here of dropping a small block 351 in these cars; I'm sure one of them will chime in. For me - for the money I'd do a build on that big 390 instead. I'd HATE giving up all that torque and all those ponies.


Forum Moderator
Staff member
unless you're wanting to drop a Terminator 4.6 into your Bird I agree with Danny. the standard 4.6 would be gutless in your Tbird..... like 225 hp gutless
I had a 1996 Mustang GT with the 4.6, it was 215 HP. A modern 3.7 V6 has more power! Also, the 5.0 was 225 HP.


Active Member
The only justification would be if the 390 is siezed or ruined and you have that little motor from something else lying around. But bear in mind "H", that car has a lot more steel than the cars made today and it's a load to push around. It's designed for that high torque, high HP big block. You'll lose some weight with the motor swap but not what we used to term "a passenger's worth". It will not glide effortlessly around town anymore (well, mine does).
Thanks Danny, Biddle, and Highwaymanrte66!
My reasons for wondering / thinking of swapping were: 1. Yes, I have the 4.6, w/ tranny and harnesses from my rusted out '96 T-Bird. 2. Yes, the 390 does need work but I'm thinking possible intake gasket - doesn't idle. 3. I am fond of the 390s but NOT the emissions air pump. Back (way back!) in the day I had a '63 1/2 Galaxie w/ 390 that gave 360 hp on the chassis dyno. at tech school. 4. I like the idea of the fuel injection / electronic ignition. I do remember hearing the "passenger's worth" comment. So guys .... deferring to your knowledge - is there , do you know of any retro fit kits to convert to FI, EI, and serpentine belt with an idler to eliminate the air pump? The '66 T-Bird is factory air equipped.

Thanks folks, HWH