Hughes heh237/242 in a 360?
I have been thinking about adding another fuel tank in the trunk LOL
That ain't the
[email protected] cam! sucking your tank dry!
Nor in the 3.55s by themselves.
I installed an A833-overdrive behind my 367 and a GVod behind that, which I used as a gearsplitter; and double od on the hiway.
With 3.23s and 28s it was was 65=1400
With 3.55s and 27s;, 65= a tic under 1600.
That 223/230/110 (270/276 advertised), cam easily pulled that, and with accompanying timing changes, pulled mpgs deep into the 20s USg.
At 180/185psi cylinder pressure, and 3.55s and a 3.09 low gear, that combo was a dump it and go deal. I mean with just a lil blip on the throttle, the flywheel unloaded into the 10.97 starter gear, and the car pulled away very nicely.
I eventually got rid of the overdrive A833, in favor of a Commando box, which also has a 3.09 low gear.
People say cylinder pressure ain't all that big a deal. That has not been my experience.
People say Quench ain't that big a deal. That has not been my experience either.
In my experience;
alloy heads, tight Q, and 180 plus psi, with accompanying timing changes, makes a chitload of torque from idle to shift rpm. I tell you a truth, I had so much bottom end, I could not use it all in first gear without tirespin. Granted the tires were 295/50-15 BFG-TAs, but they spun anywhere in the rpm band from just above idle to 4000rpm (the highest I had tried; which is 47mph in second gear), with just a footstomp (750DP).
BTW, I revved that puppy to 7000/7200, and she went 106 in the Quarter doing that, @12.9 seconds, spinning street tires until third gear with the 3.55s. IIRC that mightabin with 245/60-15s.
It is a great street cam.
If you map it out you will find that using the advertised specs; power duration plus exhaust duration comes to 227degrees. This is a good number for a street cam. In at 106, that is 119* to compression and 108* to power; both are reasonable numbers.
But with a 360 I ran it at 110/straight up, changing that 119 to 115, and the 108 power to 112. That's one of the benefits of having a preponderance of torque; you can give some up.
And at 112* power extraction is the beginning of fuel economy.
You may know the following, IDK; but to save someone else from this lack of bottom end thingy, caused by lack of pressure; I thought it would be worth mentioning.
Here is a comparo;
First; my 4.04x3.58=367 combo,
Static compression ratio of 10.8:1.
in at 106*/ 930 ft elevation
Effective stroke is
2.86 inches.
Your dynamic compression ratio is 8.83:1 .
Your dynamic cranking pressure is...........
181
V/P (Volume to Pressure Index) is
...........159
and retarding the cam;
Static compression ratio of 10.8:1.
in at 110*/930ft
Effective stroke is 2.77 inches.
Your dynamic compression ratio is 8.58:1 .
Your dynamic cranking pressure is.............
174
V/P (Volume to Pressure Index) is
............. 148
Notice I gave up 11 points of VP, and 7psi cylinder pressure, to get ~200 operating rpm at the top.
Second; in a 340; 4.04x3.315=340
Static compression ratio of 10.8:1.
in at 106/930ft
Effective stroke is
2.64 inches.
Your dynamic compression ratio is 8.80:1 .
Your dynamic cranking pressure is
.............180
V/P (Volume to Pressure Index) is .......146
Notice at the same install of 106*, both engines are making about the same 180/181 psi. But
notice the change in VP, which is a performance measure that can be used to compare the bottom ends of various engines and cam installs.
Read about VP here; V/P Index Calculation
it drops from 159 to 146; why is that?
Both engines are at 4.04 bore, and both are at 10.8Scr; so the difference has to be in the stroke. Notice the effective strokes; 2.86 in the 367, to 2.64 in the 340.
Ok so now, lets reduce the Scr of the 340, to burn pumpgas
Static compression ratio of 9.8:1.
Still in at 106/930 ft
Effective stroke is 2.64 inches.
Your dynamic compression ratio is 8.01:1 .
Your dynamic cranking pressure is..............
159 see note1
V/P (Volume to Pressure Index) is .............
129
Ouch!, you see the new VP of 129? That is about what a good 5.2 Magnum puts out. and so that is what a 340 with this combo, will feel like, as to bottom end. And that is why you need the 3000TC to get moving.
Note1;
with iron heads;
160 psi is pushing the detonation limit with open chambers
165 psi is about tops for a tight-Q design, and 91 octane. unless you are YR, then;
170 or so is for a pro-built combo
with alloys, and tight-Q
170 is nothing
185 is still on 87E10; been doing it since 1999
200 is what some guys on FABO have reported, still on pump gas, but requires careful timing.
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My Chevy Orlando Direct Injected VVT 2.4liter 6 speed,2500TC, pumps 220 psi and runs 87E10; and makes 167hp at 6700 on that; Yippee! Boy you can really feel that VVT kick in at 4500,lol. Truthfully, I have never found that Orlando to be underpowered; and I rarely venture into the 4500 Plus arena. I'm guessing the gears have a lot to do with it.
vroom, vroom, vroom, vroom, vroom, vroom, 6 gears; and into 3rd by 40/50 clicks Wahoo!
