The first is correct.
The second is normally "If Tom had had more money, he would have bought a fast car", but your example illustrates a common substitute used in everyday speech.

The first focuses on what Tom may do in the future (depending whether he gets more money!).
The second focuses on what Tom did not do in the past (because he didn't have enough money!).

Hope that helped.

CJ

2: Tom doesn't have any money now, but if he did [have money now], he would have bought that fast car.

JT:
You're getting as good as Mr. Pendantic in the humour department!!!
Jim

JT,

You could be right about the "too strict" part, but even under your interpretation the sentence bothers me, which will become more clear in a short while.

Nevertheless, I can accept the possibility of the following, which I think fits right in with your point:

If Tom had half a brain, he would have bought that car.

Here we are saying that Tom, because of his general failure to recognize good deals when he sees them (part of his character "now" and "then" and "always" - "eternal present"), did not buy the car ("then") -- that he would have bought it, however, if he were smarter about purchasing cars. He didn't buy it then because he doesn't have (even) half a brain and never did, i.e., he isn't (and wasn't) that smart a person.

I don't sense that same "eternal present" idea in "If Tom had more money", because having sufficient money is not the sort of thing that is part of a person's character or anything that can be thought of as "eternal present". It's a very time-dependent situation. Today you have enough money, tomorrow you don't. Further, the having of a sufficient amount of money has to occur at the time of the buying, not later.

Now if you want to change the original sentence slightly to suggest that Tom is/was rich ("eternal present"), then we might have,

If Tom were a rich man, he would have bought that car.

which sounds all right to me.

But I just can't get my brain around,

If Tom now had/has enough money to buy the car (and he doesn't), that means he would have bought it (then), but he didn't buy it then because he doesn't have enough money to buy it now.
[Side bar: I can't see how you don't find this hilariously funny. It's an absurd string of words!]

I suppose it is my failure to wrap my brain around "didn't buy then, because not enough money now" that leads me to interpret the whole sentence in the past: He didn't buy then because not enough money then. So to me, as I've said, "if Tom had" is just a variant of "if Tom had had". The only way I can understand the sentence as you interpret it is through mental gymnastics -- a forced reading. But if it works for you, that's cool.

Jim

Whatever. I'm sticking with my original response, which I think is succinct and accurate, and a very fine-and-dandy way of answering the question:

The first is correct.
The second is normally "If Tom had had more money, he would have bought a fast car", but your example illustrates a common substitute used in everyday speech.

The first focuses on what Tom may do in the future (depending whether he gets more money!).
The second focuses on what Tom did not do in the past (because he didn't have enough money!).

Hope that helped.

CJ

PS.

The original was:

If Tom had more money, ...

My take on 'having more money' differs from yours. I don't see this as having anything to do with being in a habitual state of poorness.

I am not "habitually" poor; yet, there are many things I would do differently "if I had more money"!

CJ