Well since most of us, or at least a lot of us, are running about 1.1 or better hp/cid, .040 is about 7 hp at peak.This is about a half, or almost a half, a cam-size.
But the boost in ftlbs at low rpm is a welcome thing with a stick-car.
But mostly, I have a 4.04 x 3.58 cuz I can sorta call it a stroked 340 which elicits oohs and aahs at car shows whereas 367, invariably brings out the ignoramuses who parrot the "you shoulda put a 340 in there" mantra.
I coulda put a 340 in there, if I wanted to be slower with the same parts I chose.
In fact I had 4 of them sitting right beside the 360 on decision day.
I mean why settle for a 340 in this day, when you could have over 20 cubes more for the same money spent? Stick cars especially like the extra oomph off the line, Cuz we don't have the extra TM in the TC, which can be very significant. So for us, the 22 additional cubes, and the one size smaller cam, adds up to a stronger punch off the line a much stronger midrange, about the same top-end power, and more mpgs with perhaps one size smaller rear gear.
Here's a comparison
First a 345 cuber(4.07x3.315), with a 268/276/114 cam in at 110
Static compression ratio of 10.3:1.
Effective stroke is 2.57 inches.
Your dynamic compression ratio is 8.21:1 .
Your dynamic cranking pressure is 165.35 PSI.
V/P (Volume to Pressure Index) is 133...............................................133
Second, a 367 (4.04 x 3.58)with a 262/270/110 in at 106
Static compression ratio of 9.75:1.
Effective stroke is 2.95 inches.
Your dynamic compression ratio is 8.21:1 .
Your dynamic cranking pressure is 165.35 PSI.
V/P (Volume to Pressure Index) is 150...............................................150
Both are set up to run the same Dcr and cylinder pressure, at about the max for pump gas and closed chamber iron heads.
Notice the VPs, 150/133 = about plus 12.8% for the 360. This will allow the 360 to run 3.23x2.66 (M/T) for a starter gear of 8.59,times say 200ftlbs take off=1718# at launch.
against the 340 with 3.55x2.45=8.70 x an instantaneous say 1.7 in the TC =14.8 times (say at 2800TC and) 177 ftlbs=2624# instantaneous, falling to 1562x1.1(lol)=1718# just a short ways out. So this makes them about equal in the lower rpms, in first gear.
Then at peak torque, the 360 is gonna make maybe 420 to the 340s say also 420. But the 360 is gonna make it at least 200rpm sooner.
So the 360 at 49mph and 3750 will be putting down 2468 road ftlbs, in 2nd gear.
and the 340 at 49 also in 2nd gear will be spinning just 3300 rpm(5% slip) , no where near its 3900 torque peak. But let's say it's making 95%, or 380ftlbs; then 380 x1.45x3.55 x1.1 in the TC=2152
But let's wind 'em up to the power peaks. I chose 5200 for the 340 with the 268, and 5000 for the 360 with the 262. And I chose the same power level for both,say 360hp for kicks.
So lets bias this for the 340 at the top of second gear. Ok so 360x5250/5000=378 ftlbs. and 378 x3.55x1.45x1.1TC =2140# @74 mph.
So lets compare this to the 360 at 74 mph
This will be 5671rpm, so we will be on the downside of the curve quite a long ways in second gear. Lets guess the 360 is down at 335hp so about 310 ftlbs. Ok' 310 x 3.23x1.91 = 1913# so she's down 11%.
So lets take her up to peak power in the 360 in 3rd gear; this is 360hp/343ftlbs, and 343 x 3.23 x 1.40 =1550# at 89mph.
Now the 340 at 89mph, is doing 5976 rpm and is 776 rpm past its prime, so I'll guess 300hp or 264 ftlbs. So 264 x3.55x1.45 x1.1=1492, so it's down 4%
Now let's take them both to 100 mph.
So the 340 car will have to be in third, and that gets her 4630 rpm, about569 rpm below peak power, so I'll guess 380#. And 380 x 3.55x1x1.1= 1484 ftlbs.
Next the 360;which is still in 3rd gear@ 5618rpm, or 618 past it's power peak, so I'll guess 320hp, or 343 ftlbs. And 343x3.23x1.4=1548 ftlbs and so it's up 4.3%.
So I'm gonna guess they'll run neck and neck to the stripe.
But the 360 will cruise 65=2608 compared to the 340 at 2867(zero slip), or plus 259rpm. So that gives the nod to the 360 for fuel-economy.
Now let's talk about overlap and power extraction. the 340 cam has 44* overlap compared to the 360 cam at 46* so that's a wash,
And the 340 has 104* extraction as compared to the 360 at 111*, so that 7*/6.7% gives the nod to the 360 for fuel economy. Again.
If I were to guess; the 360 will get at least 4 mpgs better in point to point steady-state cruising at the same speeds, mostly cuz of the lower cruise rpm
And lest anyone missed it, the 340 runs 10.3Scr to the 360s 9.75 for the same Dcr/pressure. At zero-deck the 340 needs about a 62cc chamber, compared to the 360 needing a 72cc chamber. Both for a .039 gasket and 5cc eyebrows.
so to recap; the 360 will need less cam and less gear to trap with the 340 car, but cruise 259 rpm lower, and extract more energy out of every gallon of gas consumed, mostly while cruising.
And the part I like is when I stomp it at LOW-rpm, I don-need-no-steenking hi-stall; I got VP.
All pure speculation, your results may vary.
But yeah, as to the price of them, up here they still are not worth much,which is why I've been hanging on the 4 or 5 I got. But I've had them now since the 70's so............. maybe it's time ....................
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