1986 CADILLAC FLEETWOOD BROGHAM
Discussion Starter · #1 ·
What motors will fit a 1986 fleetwood brougham? i have the 140 hp 307-y. What all will i have to change if i replaced my 307
I though about it a little longer and my theory about the 500 fitting in fine wasn't exactly correct. The largest engine that could go in to your car, without any modification to the dimensions of the engine compartment is a 425. The 472 and 500 are big block motors, so you will have to increase the size of the engine compartment to make the fit. I don't know by how much and what, if anything, you would have to sacrifice to make the fit.So lets take a 76 500 Cadillac, with around the cam cam specs as a LS1, made a pathetic 200 hp. And the LS1 made 350 hp.
To each his own, I would keep my options open. More work to put in newer engine, but far more efficiency and better emissions. But it isn't a no brainer drop in swap. A Cad 500 would be a fairly easy swap in comparison.
the 425 was over 100lbs lighter than the 472. It was slightly smaller, so they had to have changed the dimensions. Maybe for economical reasons they cut out some of the dead space between the cylinders.If memory serves the 368/425/472/500 are identical dimensionally engines. So they all fit.
in order to make it a vin 9 engine youll need a set of 5A heads and A4 intake along with the parts you listed. the Y engines heads swirl ports are too small to make any real power and can only be used with the stock intake. if you get a set of 5A heads you can use an edelbrock intake. if it was me id just find a 350 rocket or a 403. the extra torque will launch this big boat.To modify the "Y" engine, you need a performance cam, stiffer valve springs, a larger vibration dampener, and a high flow carburetor. "9's" also came with duel outlet exhaust, so you can get a new exhaust system installed. Being that the "9" still used a feed back carburettor, you may need to change the computer (otherwise it may starve the engine and throw rich codes).