And I will never understand how a budget build 318 morphs into big cam, big heads, big everything; but the stock pistons are still way down in the holes, requiring a hi-stall now, and usually gears. You guys crack me up. The only Thing still 318 is the displacement.
And like I said right in the beginning; on a tight budget, 325hp from a 318 is no small thing.
And now for the ultimate budget build;
since the hi-stall and gears are a given,
just install those right now and leave the engine alone; you will be amazed at how a 2800 and 4.10s can wake up your Duster.
back in 74 the lowly lo-compression 4bbl 360 was rated 240 NET. What does that calculate to at the the crank? Would it be 275/285? What would it take to get that to 300? Ima thinking just headers, a free-flowing exhaust, and a decent tune. Next, just swap that pressure-killing 340 cam outta there, and install fresh cold air. Quick and easy 325hp; and cheap.. Not to mention the mountains of tire-shredding torque.
But I get that you 318-lovers might want to spend wheel-barrows of cash just to be able to say you did it with a 318, and so what if it cruises the hiway at 3200rpm, sucking copious amounts of wrong-grade gas. How is that helping the budget-conscious OP?
I mean, lets add this up; for a 318,
my plan is;
hi-stall and gears; 4.10s will get you 5000=60mph@10% slip, in second gear.
Your plan is
starting to look like; big-valve heads, moderate cam, 4bbl, plus the headers and exhaust, ................... but no pistons , so no cylinder pressure to speak of, so here we are back at; plus the hi-stall, plus the gears
But for a 360, my plan is to just drop it in with dual exhaust and drive it; 2bbl and all. The ultimate in a budget-friendly, smile-creating, tire-frying, satisfaction.
EDIT(here to bottom)
for you 318 lovers
Your love for all things 318 has made you budget-blind. The epitome of HotRodding has been from the beginning, and forever will remain, swapping in a bigger engine.
Nobody cares if your whatever displacement street-engine has whatever horsepower, the questions are; how far will it lay blackies? and how quick can it get to 50/60 mph? Does it haul the mail, and does it look good doing it?
I put it to you that a 110/120psi lo-po 318 with all the big-stuff bolted onto it, is still, at it's heart, a lo-po engine, and will remain so, until you take it apart and give it a new hi-pressure heart.
To the OP, a power number on paper, does not guarantee a smile at days end. To make power, principally, requires rpm, and rpm means a higher-rpm cam. With no other changes; a cam that operates at a higher rpm, does not do well at lower rpms. The higher it operates at, the more bottom end has to be sacrificed.
The 318 already starts life as a low pressure engine. For what is was born to do, it's meager pressure was mostly always adequate. But that same low-pressure, immediately make itself known, in the performance arena; showing up as a loss of power at low rpms. As a streeter, the vast majority of the time, your engine, especially with 3.23s, will be stuck trying to operate at those low rpms. In First gear with 3.23s and 27s makes the gearing to be 10mph per 1000 rpm so 3000=30mph, the end of the low-rpm window, and just getting into the midrange. If you put it into Second, the engine goes pretty dead.
Installing a 340 cam or one like it that has an Intake-closing angle of 64*, in an 8/1 318; the Wallace Calculator predicts a CCP of just 118 psi@900ft elevation. At such a low pressure, there will not be any tirespin, at least not both of them.
And so, with your tires married to the road, your engine IS STUCK in the lo-po mode to about 30 mph. The only bandaid is to install a convertor with higher rpm stall, to get you thru and past that stinking lo-po window.
Ok but, at the other end, with 3.23s, the stall is no longer of any concern. Say that big 268 cam power peaks at 5000 and you spin it to 5500. With 3.23s, that will be 50 mph at the top of First gear. The power may begin arriving at 3500, probably at the earliest, which is 35mph. So then, to be in the fun window, you gotta be in the zone of 35 to 50 mph; But you gotta get there first.. Outshifting First at 5500, the rpm will drop to 3250, and your engine is struggling to get back "Up on the cam". Which is now gonna take a lil longer.....
But anytime you are at under 30mph, your engine will forever be in lo-po mode, lower even than when it was stock. 117psi CCP is pretty stinking soft.
But hey, don't pay any attention to me; according to some, I am a 318 hater.
But from me, you at least get the truth. which is in part;
I strongly advise you, that since you are gonna need a hi-stall and gears, and a "posi" anyway, you might as well just do them first, and see what happens. The buy-in is a fraction of what the 318 lovers are throwing at you. and the ratio of dollars spent to satisfaction is, IMO, incredibly high.
FYI:
I ran a 2800 and 4.30s, behind my lo-po 318LA for one winter, but was so impressed, it was early July before I put the 367HO back in.