Is it possible to build a new car at home DIY based off an old car chasis?

Question

So, I live in Mauritius and I am an amateur car enthusiast. I wanted to build a 450+ HP car in my garage (I, fortunately, have all the necessary tools). My plan is to buy an accidented car, strip off the engine, and anything related to that. Then, replace the engine with an American crate engine like those from GM motors LS or Chevy 427 engines, do a forward to rear-wheel conversion and put the engine at the back. Also, make CNC mould for a new body and using fibre glass and carbon fibre rebuild the body. But the issue is that I am unable to get any intel regarding this type of work on this island. It would be very helpful if someone can guide me through all of this and give me some information. Thank you very much fellow StackUsers.

EDIT: Following @Pᴀᴜʟsᴛᴇʀ2's comment, I realised my mistake and narrowed down my broad question to very specific information i was looking for:

I have to import all the parts that would be used in the car. Therefore, I would be very glad to be able to learn a few things from the community before i got started:

1. What do i need to be able to swap a completely new unrelated engine to another complete old unrelated car chasis. (i mean apart from the engine itself e.g carburator, flywheels, drive train, harmonizers, etc)
2. Do i need new transmission or can i use my old transmission (automatic)
3. How can i convert the car to a steptronic or manumatic design? Is that even a possibility?
4. Should I use aluminium bars to make the frame or iron/steel rods should be employed?
5. what is the best engine (450HP+) that the community recommends?

Answer 1

The basic answer to your overall question is: Yes, you can do this. But nothing is as straight forward as you'd think it should be.

1. What do I need to be able to swap a completely new unrelated engine to another complete old unrelated car chasis. (i mean apart from the engine itself e.g carburator, flywheels, drive train, harmonizers, etc)

To do this you need lots of time, money, and ability. It depends on your donor vehicle and how complete it is.

2. Do I need new transmission or can i use my old transmission (automatic)

It depends ... if your original transmission works for you and suits your needs, then yes. If it doesn't, then no.

3. How can I convert the car to a steptronic or manumatic design? Is that even a possibility?

To do this the most simplistic way is to start with a vehicle which has one of these options already installed.

4. Should I use aluminium bars to make the frame or iron/steel rods should be employed?

Steel is usually your best bet for any type of frames. Aluminum will stress fracture given enough time and abuse.

5. What is the best engine (450HP+) that the community recommends?

This depends on what you want. There are many different stock engines out there today which will provide this level of horsepower. Figure that into where you start with your build. (ie: There is no "right" answer here. It's all in what you want.)

Answer 2

If your neighbor were to build a 1/4 scale steam locomotive from scratch, he would finish before you, based on the scope of the project as you are defining it.

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You are far better off streamlining as much work as possible. For instance, if you are building an engine old-school with quad Holleys, it is very difficult to reach 450hp, and it happens at totally impractical RPM ranges. Modern fuel-injected engines can do it, however they are highly computerized and tightly integrated with the transmission, fuel injection, smog features, etc.

So you are much better off picking a complete powertrain package that works well together, and keeping it together - from MAF to the trailing oxygen sensor, from EGR to VSS, from body control module to fan relays. Otherwise you are sure to find yourself burdened with a huge array of highly technical, highly specialized problems that would be difficult to crack if you lived in Livonia, Michigan and knew all the bars where all the engineers hang out. Do you really want to spend your hours trying to figure out how to match a 4000PPM negative closure VSS to a 3000 PPkm positive closure one? A few such nitpicky, deadend-laden, time-sucking challenges might sound like fun, but when your punchlist has 49 of them, it becomes inevitable that you abandon the project in frustration.

So for instance if you want a mid-engine powertrain, obtain a bone stock front-wheel-drive powertrain and locate it to the rear. It is far, far easier to "hop up" a powertrain that is complete than try to hork together a bunch of incompatible stuff.

The same advice applies to bodies and chassis. You won't find many chassis pre-kitted for mid-engine. So you will need to select a chassis that is convertible. This is where a long and careful search is a better idea than trying to adapt a poor choice with mass application of engineering skills (that you don't have).

Can anything be done? Yes. But projects succeed when you are very calculating about whether it is the best use of your time.