318 La with 360 heads
In my crystal ball I see 10.7 Scr and an Ica of 57* @800 ft.
To make 10.7Scr requires a maximum total chamber size of 662.3cc/10.7less 1=68.2cc on a 3.94 bore. Very doable with a closed chamber alloy head.
You can get the 57* ICA on a multitude of cams. This is a very common area for mid-performance cams.
For instance; a 260 advertised. in at 107.
On a hydro, that could be 216 to 212 @.050 That'll make a stout 318@180psi; not 350 hp but in a streeter who cares, cuz with 2.76s she will only hit 3450@60mph with 10% slip and 80" tires (25.5s) .. 3.23s would get you 4100. The power peak with a 260 hydro cam might not come around until 4800. So with these kinds of street gears, absolute power means about nothing. That mythical 350 hp is waaaay outta sight, so you might as well built for mega-torque at where you need it; from 3450 with 2.76s, to 4100 with 3.23s.
To take advantage of a 4800 power peak, outshifting at 5200 with good heads, will require 4.10s for 60=~5180. How many streeters would be willing to run 4.10s full-time without an overdrive.
IMO, a 318 owner will be waaay happier having a tire frier in first gear, that pulls stoutly to 60mph in second, irregardless of it's absolute power rating.
A solid lifter cam , for the same
[email protected] hydro rating x1.5=.012 valve opening, might be over one cam size bigger than the hydro, so say
[email protected]. And that is a funtastic street cam. It will push the power peak up about 300rpm so say 5100, and now those 3.23s are looking mighty fine.
That 180/185 psi is now cooking the tires from a stop all thru first gear, and probably lighting them up at will to deep into the 30s mph. Sixty mph in Second gear with 3.23s is gonna get you about 4400 rpm , a lil short of the proposed 5200 shift rpm, leaving you with some dynomite passing gear power to 5000=~75 mph.
I mean, IMO, in a 2-gear streeter, peak-power should not be the target. Having the right midrange power for every occasion is gonna make a happy driver. You can only ever hit the power-peak once in any zero to sixty speed contest, and that will be in first gear with both tires blazing; and you don;t need 350 hp to do that. Heck, you don't need even 300. There was never a 3.23 equipped 340 that couldn't do that. Heck, even a 230 rwhp 5.2 magnum can do that. So you might as well say ~270crank hp. Any old 318LA with compression can get there, without even breathing hard. That's only ~.85 hp per cube.
Think about this, those early 340s spun both E70-14s to well past 60 mph. I never had one that couldn't. Even the last one I had that already burned a lotta oil, still spun 2 gears.
Anyway,to re-iterate what I would do;
flat-tops at +009 deck, .039 FelPros, small closed chamber alloys, targeting about 10.7 Scr for a 57*(@.012 valve open) Ica with a fast-ramp, tight-lash, solid lifter cam; then all the usual bolt-ons.
That's what I would build. And I would run it with 3.23s, and I would try the stock TC whatever it mightabin. I like me an 850 Carter rated TQ spreadbore for this combo. Why? For the visceral roar when the secondaries announce their arrival to the party.
Like I said; If I was building a 318, which at age 67, I can't see me doing, that's what I would do.
Except;
I would aim for more pressure, and
I would run ~4.10s with an overdrive,lol., and
Probably a manual trans.
And no skinny donuts in the back, cuz spinning ain't winning,lol.
