hey man, sorry to hear your car gave up it's timing belt...
don't mean to but in on your decision, but I like your creativity & desires...
one of the biggest mistakes I see most amateurs make in building there first car is, starting with the car they have, & not realizing they built the wrong car till there too deep to turn back, then, getting in even deeper... & in the end, it can just turn into a big waste....
now this is not to say that just cause a car is cheap or free, that it's not worth investing in a total redo either...one off my best custom cars that I've built started out as a car I traded for an alarm installation.... total cost to me was about $75 & 3 hours work...
the car had a bent frame, had over 150k on the original 4100 crap motor, & had the most ugly blue velour interior... but it had a straight body, & it was a car that I loved style wise.... I proceeded to rebuild her from the frame up... swapped out a newer low mileage frame with abs brakes... complete new everything... turbocharged drive train with best of everything.... custom body mods, paint, rollbar... etc...
I must have put over $30,000 in that car over the years, & I had many good times driving & racing it... dove it for close to 4 years, then, she's in storage & being rebuilt yet again...
the car I am talking about is my 83 caddy coupe, "turbocad6"... it's also the first car that I ever put a computer in....I've built many many other custom cars through the years, some that started with 10 & 15k cars to begin with, but turbocad is by far my favorite, & the one car in my collection that I know I'll never get rid of.... I know I will put a bit more money into her in the next few years, but I don't regret one bit of it.... I love this car
weather it starts out as a $75 car or a $17,500 car doesn't make much difference if you love the car, but of course, the newer & minter the car you start with, the less work you'll have to do.... if your going to redo EVERYTHING anyway, then theres not much advantage to paying for really nice everything to begin with.... for example, if you know you want a custom paint job & interior, theres no benefit to paying for a car with a mint paint job & interior to begin with, cause it'll just be wasted anyway when you redo it...
,but don't forget to factor in that a clean nice car will be nice in all other respects mechanically, where a beat up car will need more restoring & replacing... again, if you going to redo it all anyway then that's fine, but it sucks to HAVE to redo everything too, if good stock would have been good enough...
but then again, for the average guy without the facilities & resources available, it usually is an advantage to starting with a decent car to begin with, that's why all these guys keep saying "why man... that's stupid"... cause the average guy isn't going to want to start with a car that needs EVERYTHING redone unless theres a real good reason to do so... the average guy is not going to see any reason to putting this much time & energy & resources into a mundane old average car to begin with.... but what anyone else thinks is really irelivant... it all comes down to how YOU feel about the car....
the best way for you to decide if this is really something you want to pursue is to ask yourself one simple question....
"If you had $16,000 in your hand right now, would you take that money & do your dream redo on this car, or would you go out & look for a new car?"
if you can honestly answer that you would redo this car then I'd say go for it.... **** what anyone else says,... but if you think that your answer would be different & then realize that the only reason you want to do that car is cause you already have it, then just throw a new belt in it & decide exactly what it is you really want to put all your energy & creativity into...
either way, good luck with whatever you decide