D50394
IIRC you are running a turbo,right?lol.
OP;
275/50-15s to 275/60-15s is about a 9.4% difference. All mopar chunks from 3.55 down(in numbers) are also about that same 9% difference. [From 3.55 larger (in number),they are about 5% change per size.]So the tire swap is way easier than the chunk swap. Unfortunately, it's a one-size swap, from minimum to maximum. Still 9% at hiway speeds is about 5 to 6mph, or 200 to 300 rpm,or about the same as a lock-up convertor.
Is it worthwhile? It wasn't for me. But neither was swapping chunks.
Trying to get a 74 Duster into the 12s with a stock LC long-block and bolt-ons,is gonna be an exercise in futility.You are gonna need a power-adder.
The turbo idea, solves this issue very neatly. Never worry about chunks, or tires, or lock-ups, again.Just put it in D,and let the turbo do the work.
If you want to really impress yourself,run two of them; a little-one and a bit-bigger one;staging them.The little one will blast you off the line, (think VW Jetta with a 1.8liter),and the lil-bigger one will carry the power through the midrange, and beyond; in effect eclipsing perhaps a stroker. If you get it dialed in just right,and keeping up in the traction department, you will have a force to be reckoned with.
These ideas are not mine, nor are they new. Nor are they easy.Most of the fabrication work will be custom, especially the big-N-little. The nice thing about duals, is that the secondary turbo can be remote mounted, while the smaller one, is, well, small.
The smaller turbo can be replaced with a little shot of N2O, to get the bigger remote turbo spooled up sooner. But refilling the bottle all the time is not for me. Some guys have made the remotes work really well.
So basically, I think the things that turn people away from this combo are;
a)fear of the unknown,
b)unwillingness to not have a car to drive while the fab.work is going on,and
c)the fear that if one cannot finish the project all this money is tied up and you may as well have just set your cash on fire.
But here's how I see it;
Building a 350/400 SBM is neither cheap, easy, or particularly quick. It is easier if you sublet it, but you have to trust the builder. Then when the engine comes back, about a week later the tranny blows up and you have to spend more time and money. So now you have a power-house but stock teeners are embarrassing you at every light. So you pull the tranny down and install a big TC. Now you are sling-shotting off the line and the racing bug hits you. You go to the track, and find out it is really fast, but not very quick. So next track day you show up with 4.30s and the ET is getting there. But you are burning up the tires most of the way down the track. So back to the drawing board. You narrow the rear-end and put some serious rubber back there, and off to the track you go. Ok now she's 60 footing pretty good and the ET is where it aught to be.
Of course, along the way, you discover that the ignition system cannot keep up, nor can the cooling system, nor can the fuel system. So all of those had to be upgraded. Furthermore, getting the beast slowed down at the big-end was a real challenge, so bigger better brakes were needed. By this time you are into the project for something like; engine=7000,+tranny/TC=3000,+rear=2000,+suspension=2500,+ig/fuel/cooling/other=1500,total over $16,000Canadian.So maybe $12,000Usd.
And what do you have? You have a purpose built machine that goes like snot, stops on a dime and is able to burn up fuel at an alarming rate,all summer long;no matter what you try. It is loud and obnoxious and is a cop-magnate.As soon as it gets cold out, into hibernation it goes.After a while nobody will ride with you cuz the tranny wants to break your neck on every shift, and 65mph is screaming down the road at 3400 rpm.So you end up cruising by yourself, wondering if you made a mistake.And eventually after a few years the car has accumulated 12000 miles; or about a dollar a mile, and you're just not that interested in driving it anymore. So it languishes under a tarp, until the body returns to dust,the rings seize in the bores, as do the valve-stems, and the valve-springs fade away.
But as to the turbo car, when the fun has run it's course, you pull off the turbo kit, and sell it to someone here on FABO.Then return the car to stock, and sell it; or,continue to drive it 4 seasons until there is nothing left to drive.
If the car doesn't ET that well, heck it's boosted; crank it up till it's too fast for you. If it blows up, hey a replacement used engine is about $200 bucks, and next weekend you are back in business!
Ok,anyway, that's my dream.
I already have the engine(s) lined up.
Sooooooooo,where should you start?
I say, how deep are your pockets and what are you hoping to to achieve?
Now I read that you want to qtr mile it,
And I did not see any reference to street driving.
But I did see such things as; eventually,and morph, and long distance cruises, and good street manners,etc.
A 12 second NA-car is or can be a real nice streeter. And once you are into it, the bug may bite harder. When this happens you may be tempted to throw a lot of money at it to go just a little bit faster. Then the thought comes to you that you've got all this money tied up in a car that accumulates mileage at an microscopically tiny rate. So to get some value out of your dough, you may decide to run it more as a streeter. A 12 second streeter is very much fun.
I think a turbo is a viable alternative for you. Easy 400hp. Easy torque monster.With 3.23s easy on gas. Cruising at 2500=65 is nice. Not having a 4000TC is nicer. An engine that doesn't overheat,idles like a stocker, has factory manners,etc; these are all good too.
Trying to get a 74 Duster into the 12s with a stock LC long-block and bolt-ons,is gonna be an exercise in futility.You are gonna need a power-adder.
