I just have to butt in here.Theres something I dont get. You already have a 360, not 20 ft away. I heard you say it needs a rebuild. Then I hear you talk about spending all this money on the teener. I can almost guarantee you, that you will be disappointed in that 318 after you spend alll that time and effort on it. That 84 D-100 is not a lightweight Dart. It needs torque to get it moving. That means more cubes. plain and simple. Any performance cam you put into that 318 will push the tq up higher in the rpms. That means your gonna have to slip the clutch more to get going, and once is out it will still be a dog until you get the revs out to where the tq is.And the worst thing you can do to it, is to put that 340 cam into it. Headers/duals are good. The rest? Unless you change the rear gears, is a wash. Have you weighed that truck?
You may be thinking; who is that jerk?(me).Well, I have exactly that D-100 tank. And The reason I have it is My son begged me to sell him my snappy 318 winter motor out of my Formula S. He really liked that motor. I explained all this to him. He wouldnt listen. He made me an offer I couldnt refuse. Well of course that little motor fell flat in that beast of a truck. So he begged me to sell him one of my diffs. So he coughed up the cash and I put in an 8.75 set-up with 3.55s. Well that woke it up. A bit. Now it had a ton of wheel-hop out of the gate. Well theres no way a pinion snubber will work under that box. So I fabbed up something for him. Ok,wheel-hop cured. He drove it this way for a year or so, complaining about how much fuel it sucked.And how terrible the handling on it was. And this and that. And finally he wanted out. So I traded him for my winter beater; a 95 Sunfire. That truck is still sitting out in the back forty, going on 5 years now.
So long story-short; why not do the obvious; Give that 360 a quick once-over, and in she goes. 360s make torque, and thats what that truck needs. You will be way ahead in the end.
Sorry if I rained on your parade, but honestly 360 - 318 = 42 cubes. Thats an easy 30hp right there, and a mountain of torque more, right off idle. If you are cash-limited, put your money where it counts.
And if for some obscure reason you just have to stick with the teener,do yourself a favor. Before you spend a nickel on that girl, upgrade the rear gears to something between 3.55 and 3.91. Since you stated you have the od box, go 3.91s. Its all you will need until the 360 goes in.
Sincerely AJ-bin-there .
Edit; Calling that truck; a beast,and a tank, etc, are actually terms of endearment,lol.Thats just what we all used to call it. My son drove it for quite a few years. It collected all kinds of; Im struggling for the expression,character damage(?), along the way. And my rant may have come off sounding as if Im bitter about it. Heck no! We had good times together, and a boys gotta learn. After I lost my winter beater to him, I picked up an 03 Grand Am GT, as a winter beater. Well that sunfire only lasted maybe a month when someone broke into it and wrecked it. He used the insurance money to buy my GT. hah. Im still walking. Kidding, I got something else. No no, we had a swell time together. Hes still driving that GT, now with more than its fair share of, character damage,again.