230/236/110 is a big jump from 216/216/110, that looks like 3 sizes.
That will move your peak power upwards from about 4700 to about 5300, or some 600 rpm......... at the expense of losing some low-speed torque in your short stroke 318.
The 3.91s will help with that, but you may find the 2500TC a lil lazy off the line.
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I have a 230/237/110 in my 367 cuber with a 4-speed. My starter gear is 3.09x3.55=10.96. My cylinder pressure is a tic under 180. For a streeter, I wouldn't go any bigger.
Your teener/904 has a starter of 2.45x3.91=9.58, about 13% less, but you have the Convertor, so that will be close to a wash.
The difference will be in the cylinder pressure.
For your stated use;
Mainly street and a little strip use.
Im not looking to spend a bunch on cam, lifters, and springs. Worse case ill just get new lifters for my current one. Im just trying to build a fun street toy for this year. Next year im planning on building hot teen.
forget 8/1 Scr. Forget 9/1 Scr; yur gonna need some pressure.
I was much happier when I had a 223/230/110 cam, also running 180ish. With this I ran 2.66x3.23=8.59 with no complaints.
Jus trying to help.
In your case I think I would just swap to anti-pump ups and run them at a minimum preload. You will have to run adjustable valve gear and new length pushrods. I run my 367 a lil clacky, on the hydraulic Hughes HE3037AL cam.Makes great torque. Bindatway since 2005ish.
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Edit;
This;
Your teener/904 has a starter of 2.45x3.91=9.58, about 13% less, but you have the Convertor, so that will be close to a wash.
might require a bit of an explanation.
The TC has an internal Torque Multiplying function; that is to say, it multiplies the incoming torque to a new higher number when it leaves. The amount is often expressed as a multiplier, like 1.05 or 1.1 or 1.8 etc. You can apply this multiplier to your crank output, or if you don't know it, then you can apply it directly as if it was another transmission gear.
The thing is this; the ratio is highest at zero mph, and decreases automatically as the vehicle builds speed. I have read/heard of ratios as high as 1.8@ zero mph. And guys often report numbers still at 1.08 at 100 or so mph .
In your case then, at zero mph, you might expect 2.45 x3.91 x1.8=17.24 instantaneous ratio, rapidly declining to something like 2.45 x3.91 x1.2=11.5 sustained in first gear. I'm not preaching absolutes, just insight into why autos usually blast off harder.
Thus your effective starter gear of 11.5 or better is very similar to my 10.97, less than 5% difference. Which I call; "close to a wash".
And besides;on the street, there is such a thing as too much starter gear, as you can get into second gear too early with it, leaving you with nothing to downshift into at 35 mph.The math on that with 3.91s is ;
35=4750 in first, and 2810 in second. As you can see; downshifting into first gear gives you only about a few milliseconds to shift-rpm, but at 2800 in second, your teener might labor a ways until it gets back up on the cam.
So it depends on your driving requirements.
A bigger cam will extend your first gear, but when you shift into second, the engine is stuck again, laboring up the power curve, until it gets back on the cam.
This happens because of the rather large 1-2 ratio split in the 904/727.You can't change that split of 1.45/2.45=59%; but you can work with it.
A higher stall will keep you out of the soft zone.
More pressure will make the soft zone less soft.
A wider LSA will bring down the peak power, and extend the power a lil lower, so you won't feel the softness as bad; it's still there just less noticeable.
The best plan is a trans with a closer 1-2 split; but Mopar doesn't have one
, at least not among the autos.
If you think about it; your TC is acting like as if it was another automatically adjusting gear,similar to a CVT. The ratio-split is about 1.1/1.8=.61 or 61% which is very similar to your 1-2 split of 59%. That effectively adds a "bull- low: to your A904, or any trans actually............ which makes it perform like a 4 speed, but with only two pulls on the shifter.
So in the big picture; you could think of these ratios as;
(4.41 diminishing to 2.94)-1.45-1.00 If you add in the TM of the TC, it might look like this;
4.41>2.94-1.67-1.1 in Drive. If you also had a lock-up, then
4.41>2.94-1.67-1.1-1.00 .....5 gears, with a short 10% into fifth. I call it 4.5..
If you think about this sumore...
and if you needed less than 3270 cruise rpm at zeroslip, which could be 200/300 more with up to 10% slip; then;
You might consider say 3.23s with an A999 loc-up, to cruise 65=2700
Your starter drops from 3.91x2.45x1.8= 17.24,
to 3.23x2.74(in the A999)x1.8=15.93 a loss of 8%
If you needed to, you could easily make that up with; a couple of hundred more rpm in the stall, more cylinder pressure,shorter ramps on that cam, I tighter LSA, or a shorter-period cam. The penalty for running the A999, is the splits are slightly wider than the 904/727, but at your power level, this is not a very big issue.
Just for comparison's sake; here are the A999 numbers with 3.23s, compared to my Commando,with 3.55s . Check out the splits;
15.93>9.49-5.39-3.55-3.23,...........splits of; .60-.58-.66-.91
-10.97-6.82-4.97-3.88-2.76(GVod); splits of; .62-.73-.78-.71 ; I split 3rd then go to 4-od.
Why is this important?
Cuz your tires don't care how much power your engine has. They only care about how much is coming out the axles. And your combo cares about staying on the cam, to maximize the average power over time,or distance.
