Nice work..I prefer mild builds like this,because you can actually enjoy it daily,& a mild whiff of N20 is there for fieisty issues .
Re-testing 318 (dyno) after changes on Tues
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Nice work..I prefer mild builds like this,because you can actually enjoy it daily,& a mild whiff of N20 is there for fieisty issues .
MRL Performance
Well-Known Member
Nice! Bigger is not always better. Like RRR said, its all in the combo. Avg power is where its at.
More power, Less Fuel! And it good for the environment too, right? The EPA will like this thread
More power, Less Fuel! And it good for the environment too, right? The EPA will like this thread
pishta
I know I'm right....
Sub 300 HP with high flowing AL heads, nice induction and headers? No wonder the guy was pissed. Carb fans take note of CFM, never gets above 450, and the A/F seems preeeety stable, although a little fat. Nice work. A mismatched motor is just a collection of parts. Go in with a plan and you'll enjoy the outcome.
IMO, this is one of the reasons cam makers grind advance into cams. People tend to choose them too big trying to have a mean sounding engine, rather than choose one for best power.
The muscle car era engines were no slouches, yet their .050" duration figures were pretty small compared to what's usually chosen to go in an otherwise similar street engine. I've always tried to err on the small side for cams and carburetors alike. I usually don't get listened to. LOL
The muscle car era engines were no slouches, yet their .050" duration figures were pretty small compared to what's usually chosen to go in an otherwise similar street engine. I've always tried to err on the small side for cams and carburetors alike. I usually don't get listened to. LOL
nm9stheham
Well-Known Member
I generally agree with this reasoning..... 'back in the day', such ground-in cam advance was not standard. But today, I think the cam mfr's want to avoid a bad rap for poor low RPM torque with too much duration. The emphasis on, and articles extolling, peak HP is the culprit, IMO; the inexperienced get all caught up in peak HP alone,and explanations of a wide torque band for good all-around engine performance are few.
Yup. Look at the 340 cam, for example. It was "somewhere" tween 208-228 @ .050, yet how many stories have you heard of one pulling to 7K? My stone stock 73 low performance 340 in my Charger regularly saw 7K and never not once valve floated, burped or farted. It kept right on pullin.
Most hot rodders usually "start" lookin at cams in the 230ish duration @ .050, and that's already too big for a LOT of street engines.
The cam I had Oregon grind for my Mercury Bobcat project.......it is only 218 and 224 @ .050. Although being a hydraulic roller, that does make "a little bigger" than a comparable flat tappet, but still very mild. I "JUST HAD" to beat down the urge to grind more duration in, but I beat it down. lol I cannot wait to see what kinda torque that little 5.0 has with 3.40 gears and a 5 speed.
You guys hit the nail right on the head. It's not about "maximum horsepower at maximum rpm" but more about usable power and drivability for street driven cars.
BigBlockMopar
BigBlockMember
RAMM, what was the reasoning to mill the block that much and not the heads?
With the coloring on the headers, I would think there would be some more power to be had if the engine got a bit more fuel.
With the coloring on the headers, I would think there would be some more power to be had if the engine got a bit more fuel.
mguner
How many is too many?
You would gain more CCs from a full cylinder cut as opposed to the head chamber. I was wondering about the mixture a little also.... Did you get a wideband reading at WOT pull?
nm9stheham
Well-Known Member
Years ago, on most factory heads, you would not have the breathing in the stock ports to make this HP. Hence the value of the Hemi heads and heads like the Clevelands: gobs of breathing out of the factory. I decided (FOR my son LOL) with the Edelbrock heads straight away (like used in this build) just because they breathed about 10-15% better than 351C factory heads, and I already knew that head would go to high RPM's with a mild cam; the Edlebrocks would just be even better. The cam used is a Crane Z-268-H....with the same advertised duration as a Comp XE-268...but with about the .050" duration as an XE-256. 14-15" idle vacuum BTW. Chirps the tires at <1/2 throttle from a stop with 3.55 gears... good torque.
Good breathing ports and intake and exhaust manifolds + mild cam + decent CR = wide torque band for the street. Won't win the peak HP contest on the dyno, but will be niiiiice to drive.
RAMM
Well-Known Member
Cutting the heads alone does nothing for quench. I am a believer in quench and reducing power killing crevice volume.
The headers are a cheap but nicely made stainless by DNA? I imagine they are thin wall. This particular dyno shows best power from 12.5-13.0 flat the way Superflow calculates AFR. I did not get a wideband reading although I am in the process of adding dual widebands and controller to the SuperFlow WinDyn software.
Adding fuel may have resulted in more torque at the very bottom of the test but taken away HP at the top. The fuel curve was actually pretty nice and matched nicely with the rest of the engine combination. J.Rob
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