straight six in 63 rambler 440

I was just curious if anyone knew where to find performance parts for it. Or if there was anyway you could fit an ambassador engine into it. thanks.

A 63 Rambler 440 is the small American body. That means it will have a 195.6 six, either L-head (flat-head) or OHV.

There are NO performance parts available. You might luck up and find an old Offenhauser intake that takes two model 1909 1V carbs for the OHV, but that's the only aftermarket part I know of. There is a 2V factory option that would work better and can be found more easily, uses a Carter WCD 2V carb.

For the L-head Nash made a 2V head and a two carb head, and there was an aftermarket twin carb head (by Edmunds), but all of those are hard to find.

The best thing you can do for any of these engines is to have the original cam reground, assuming it's in good condition.  I had one reground for an OHV with 20 degrees more duration (244 to 264) and 0.10" more lift (0.370 to 0.470). That gave it about 20 hp at 1800+ rpm. There's nothing you can do to make it get up to speed faster though --  the small bore (3.125") and long stroke (4.25" just make that impossible. It would make a great tractor engine though! It was designed for economy, so it pulls like crazy right off idle but speeds up slowly and doesn't build a lot of horsepower.

The engine bay of the small Americans (58-63) is tight! The car is basically the same structurally as a 50-55 Nash Rambler. AMC just changed the outer skin a bit in 58, a LOT in 61 (also the firewall in 61), but that's about ALL that was changed! Only minor mechanical differences -- most parts interchange all models. That car was literally designed around the 195.6 L-head engine. The OHV fits only because it's adapted from the L-head.

With a little ingenuity you can install a small block V-8, but not the older Ambassador V-8 or the newer AMC six. The engine bay is way too short for the 64+ AMC six, too narrow for the 56-66 AMC V-8. The later model V-8 can be fitted, but it takes a lot of work. An SBC is even tight -- the Ford 302 would be the best fit as it's a couple inches narrower than an ABC, but even it would be a tight fit. Four cylinder engines are too wide on the intake side -- major work under the hood is needed to make one fit, almost as much as fitting a V-8. Small V-6s (any Ford V-6, 2.8-3.4L GMs -- 4.3L is as wide as a V-8) would be the better fit, but you need to get "hot rod" accessory mounts or roll your own -- the factory mounts put the accessories beside the engine and way too far apart for the narrow engine bay.

There is ONE "better" (meaning easier to get parts for and has a little more power) engine that will fit that engine bay -- the Ford 250 in-line six and the smaller Ford in-line sixes. Their curse is having the intake cast into the head -- which is why it will fit the small Rambler engine bay, that and they have a small bore which makes them no longer than the 195.6. You will need to change the transmission and have a driveshaft made, but it fits! See www.fordsix.com for performance parts/ideas for that engine. You will still need to fabricate engine mounts, but no major cutting on the body will be required.