360, 10.2Scr, 2.94s, 2.74low, 255/60-15s
I know, I know you said with existing parts,but here's the thing;
1-You are trying to hit too many bases.
To cruise comfortably at 68 requires a hi-way gear.A teener, in a tank,with a hi-way gear,and a 3-speed automatic,non-supercharged, just can't be a tire-fryer,no matter how much compression you throw at it.
-So if you need to use the teener, then supercharge it and install 2.94s. This will get you about 2480@68 with 27s in loc-up.The super will dial in the footpounds right off idle and you are firmly in tiresmoke . "Course you're gonna need some HD parts from the crank to the back,heehee.
2-But if you are willing to forget about hi-way NVH, then just put some 4.30s in it,keep your 4bbl teener as is, and you are done.But it won't spin the tires very far, cuz second gear is coming up real quick. For extended wheel-spin time install a line-lock and learn how to use it.
3-But if you want to go Zero to 60 quickly, with a stock-long-block teener in a 4000plus pound tank, you are gonna need two gears, cuz the teener won't carry one gear to 60,with aplomb.Relax, this takes the same 4.30s to hit 60@4936 with 27s in 1.54-second. Oh and make mine a 4bbl,any 4bbl, and headers or at least shorties with a free-flowing exhaust.Oh yeah, don't forget fresh cold air. If the engine is forced to suck up that super-thin,super-hot, underhood-air, it will laugh at the whole idea. You might as well be at 10,000ft!lol.
If you need more top-end get some heads, and an intake.
If you need more punch off the line,lol, get a higher stall TC.
If you need more power in the midrange get some compression.
WHEN nothing is enough, get a bigger engine,lol
4-I would just start with a 360, in the first place and save a ton of fooling around.
-And here's another thing. By going with a bone-stock 360 (OK maybe add a 4bbl), you can use 2.94s and keep some semblance of comfort and economy for the hiway.But since you can continue to drive the boat with the teener, you can take the time to juice up the 360,a bit.( BTW, I use the terms boat, tank and slug, cuz I had a 5th and it was all of those, but I loved her anyways, cuz she was never designed to be anything but those, and what it was designed to do,it does very well.So please don't take offense
).
-So now we have an engine (the 360)that does have the potential to hit a few more bases.
5-So; plan it out: 2.94s for hi-way, is job one. Tire frying is job two. And a quick zero to say 45 is job three, but it doesn't have to be "that" quick, cuz jobs one and two take precedence.And no more than three jobs!
Allritee then;
6-So, tires first. What? Hyup tires first. You need some tires that smoke easy, (or at least make noise)but got some bite when they warm up and get going, cuz 2.94s are gonna be a chore as it is. So BFGs it is, and Ima thinking 255/60-15s. These are tall enough(27) to look good in there and skinny enough to light up, and with 2.94s will spin a long,long,ways with a torquey 360, and have just the right amount of stick/slip, and finally;they're cheap; which is important cuz you are gonna be buying a lot of them.So that takes care of job one.
7-Next is actually making the torque to twist that starter-gear of 2.74x2.94=8.06. Whoa!,that's gonna be tough. Ok so we don't care about horsepower numbers,forget about horsepower for a bit. What we DO care about is getting those tires spinning at just off idle, cuz you don't have a clutch, and a 3500rpm TC defeats job one. We are starting with a long-stroke 360, which naturally makes torque, so all we have to do is enhance it. And job two means we are putting a ceiling at 5000 rpm. So that naturally means, you could bolt on your entire teener top end, heads and all! (The 360 stuff will work too, but not with where I'm going). The teener stuff will respond really fast from idle, pull to 5000, and help with jobs three and two.
So since I myself have run the teener top end,heads and all, on a big-bore SBM(,a 340), and know how that can snap off the line with nothing more than compression, let's write that Teener top-end in stone. We are gonna transfer all of your teener top end onto the 360 short block(with just a freshening of course). But let's keep the 360 2bbl cam with its 252/260/114 specs, assuming it and the lifters are in good shape; cuz the 252 will make all the jobs easy.This combo allows no smaller cam, than about a 58*ICA.
8-So now we just have compression to deal with. I'm gonna assume the 360 needs pistons anyway, and that the teener heads are closed chambers, and about 60.5cc. And I'm gonna work the Dcr formula backwards to walk the thin line of cast-iron. and assume you have FRESH COLD CARB AIR SUPPLY, cuz this will help with hitting all three targets, and help to keep the engine out of detonation. I'm also gonna assume the 252* cam goes in to make a ICA of no less than 58*.
9-So a 360 @ 4.04 bore has a swept volume of 752cc. The heads are gonna be 60.5 say, and the gasket about 8.9( the .039er). So targeting 8.5DCR requires;the calculator says 10.2 Static compression ratio. And that is 81.8cc. So where are we at ;81.8 less (60.5+8.9) =12.3cc in the cylinders. So assuming 5cc in the eyebrows, that leaves us with 7.4 with pistons down in the holes. And that is .035 down. But that's not quite right. We want to take advantage of the tight squish theory, for a few reasons; 1) it will help keep the engine out of detonation, and 2) we are so darn close already,and 3) they make pistons to do this for cheap, and 4) this will help us to get some serious fuel economy at steady-state hi-way speeds, and 5) it will pump up the midrange torque.
-So the answer then is not to mill the decks, cuz this will increase the Scr/Dcr right into detonation, but rather custom pistons. KB makes a series (KB190/191) that one of them has a quench-pad of .050, that can be machined off to whatever you need, to get the 8.5 Dcr .In this case about .050 less .035 =a cut of .015 easy-peasy.
10-Now there is your tire fryer recipe. It will probably even work with the stock rebalanced convertor. It might even work with less than 2.94s but that gear was chosen for jobs one and three. With 2.94s,45mph is 4500 in low gear, and 68mph is 2480ish in loc-up.
A teener can't do all of that,NA.
And you can't do it with X or J heads either without a serious amount of WORK. Magnums maybe..... EQs sure. But why spend money on stuff your combo doesn't need?
11-Ok here's a bit; If you are thinking of wussing out on the Q-Dome pistons and instead getting KB 107s, DON'T do it! These went into my 360 only a few thou down in the holes. Let's call it .010. This is 2.1cc. So your total chamber might be ; 2.1+5+60.5+8.9= 76.5; for a; too-high-for 91@WOT, Scr of 10.83, and a slightly-high-for 91 Dcr of 9.05. The squish-pad will be .039+.010=.049, still in the ballpark; so, me being me, I would try it. But if it rattles,You will have to do something drastic. Premium gas may not be the answer. You might still be able to run the cheap stuff on straight hiway,tho.But if you just can't get rid of detonation, you can move the cam a few degrees and retune. And as a final tidbit, you can get a little bit bigger cam, say a 260/114. This will drop the Dcr to about 8.8. I still think that this will be too high. So that takes us back to the KB 190s, with a custom top-mill.
12-And another bit; I suppose you could stroke your teener out to 3.58stroke for 349 cubes. Or 3.79 stroke for 370cubes. Or 4.00 stroke for 390cubes. Any of these will get you a tire fryer with hi-way gears. But the teener heads will be out; you need a new plan.
22-Now you may be thinking "I said with as much stock parts as possible". Well ok, then, go back to the beginning, square
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