103.38 on one 6.54 slip I have here

For what it might be worth you can get away with quite a mean smallblock and keep some kind of drivability and fueleconomy good enough for daily driving if you just have it tuned right and have a happy combo of parts.
15 Years ago i had a 340 with a 260+@0.050 solidroller cam in my duster and i drove that thing everyhwere all the time,sure it had less converter than optimum for racing but the thing ran excelent on the street and didnt eat endless amounts of fuel as long as i keept my foot out of it,it sure didnt fool anyone into believing it was a stock 318 when it was ratling windows already at idle and was flat out screaming when turning 7500rpm but the thing was deadreliable, and on the open roads with a soft foot fuelconcuption stayed at about 1.2Liters/10km even ran it at pretty much 1L/10Km flat in some instances running about 90km/h with no stoping or accelerations.
However this thing was probably not realy a 500Hp 340,probably more likely a 480hp 340.

Docile is in the eyes of the beholder but here was my combo that made a touch under 500 according to the wallace calculators.

.040 360
KB107 pistons zero deck with .039 quench
Shady Dell Stage II ported Edelbrocks
258@.050 solid roller
Victor 340 intake
830 carb

It went 11.16@120.5 wieghing 3525lbs in good air for here. It had a big cam, and big converter but it was very driveable. It was in the car for 5 years and did 4 drag weeks in that time. It got a best of 15MPG on the highway on drag week. I never measured it in town, but it wasn't good due the converter and my right foot lol.

Pretty easy on parts, it ate the thrust once for reasons unknown, and we jammed a new crank in it over the weekend and went on drag week the next. I changed lifters once in 5 years and I changed the springs($100) every year before drag week as insurance.

I’d expect that to easily make 500+

According to wallace that is about what it made. It had small tube headers and a full exhaust system that was probably costing it a little.

My stock stroke, 11:1, W2 head, MP intake, antique Cam Dynamics .620/.640 roller, too small carb, 360 was about 525 in decent air according to my Moroso dream wheel.

In my view 'docile' could mean power brakes should still be possible. But of course an elec. vacuum pump could take care of that perhaps these days.

Of course 'Docile' is easy to interpret differently for anyone.
Let's say, could you wait for 5 minutes for a traffic light?
How about 10-15 minutes of idling in a traffic jam, all without overheating or fouling plugs?

I’m gonna say the xe256 cam and 302 heads aren’t the kind of items I’d be seeking out to use if the goal was truly 500hp.

Maybe with some boost.

The sidewinder heads flowing an honest 265+, a small roller like a Comp XR280R, with the other stuff you already have should get you close.
Not sure how the propane fits into the equation as far as power output goes.

Powerbrakes could be made to work with a vacumpump or possbily hydroboost.

My old 340 with a 260+@.050 solid roller didnt have any problem what so ever with a 8hour lap around Västerås during a very warm cruisenight at PowerBigmeet, Thing was pretty much runing at a 800rpm idle for 8 hours straight except for one occasion when i got of the cruise to get some fuel and found myself alone on a empty street where i gave it one big step on the loud pedal and the thing sure responded just like usual.

Thing didnt even have a huge colingtsystem,just a radiator out of a 4cylind Ford Scorpio and a MRGasket 16" electric fan and never ran hot at all despite what internet toughguys tried to tell me and that was with a tallfilled block.
In my opinion its mostly about having an happy combo that is well tuned to stay out of trouble with heat and fouled pluggs.




Thats not a bad idea you have there,if those sidewinderheads are real efficient and everything else is just right they might just reach close to 500hp with that cam,

Thats actualy the last cam i ran before my worn out 340 finaly expired it sure has a long flat powerdelivery ,Its a very nice running cam in a stock stroke 340 and might be even better in a 360.

The 302-heads and XE256 cam were chosen purely for streetdriving.
Now that I've driven with this engine for some 2 months, goals might have changed and I started thinking, I *think* I 'need' more power.
A cam and headchange might be in the works perhaps.

I'm running a XR274R roller in a 496ci stroker, which has a very obvious idle. Running a stock stall convertor behind it and it's pushing against it. This engine however is quite a handful because of the long-ram intakes with 2 carbs doing kinda 'whatever they like', according to the AFR-gauges in the car.

I can only wonder how an even bigger cam would behave in a way smaller 360ci.

Propane can be seen as a 100+ octane fuel but with a little less energy.

You’ll have to decide for yourself how rough an idle you can live with.......cam accordingly..... and the final combination of parts you assemble will make what it makes.

I was talking with a customer yesterday that just finished putting some finishing touches on the install of a 418 6bbl in a challenger with ex manifolds and a stick.
That motor used a fast rate solid lifter cam, 242@.050....... he said the thing was very mellow.

How mild or wild it is, is mostly about how each person perceives it.

There is a homerun for you, one person's race motor is someone else's motor for there haller.

Very true, I personally thought the .484 hyd. had more of a lope than the DC.590" solid I changed to in my 10.1 340 and it drove real smooth on the street...nobody would probably use any of those cams today though.

The .290@.050 comp solid I ran in my 440SP motor ticked over at just over 900rpm, I wouldn't call that a wild cam either, and it was only a 10 sec. brkt car, most wouldn't go anywhere near that much duration unless all out max effort, but that was with ported 906's.

That is true. Everyones idea of mild and good idle quality can be all over the map.

But the rest if the cam and motor specs matter too. That cam might only have 50° overlap, and/or high compression, effecting significantly idle characteristics. And the stick also changes the perceived mildness as the motor is not loaded at idle like an auto.

I too would be looking at a small solid.

An XR280R in a 360 is not going to fool anyone into believing that that 360 is a stock engine and it sure wont appreciate a stock converter either,it probably wont even idle in gear with that. But it will idle at 750-800rpm until you are out of gas if everything else is right and yes it has an idle that you will notice, In my 340 it had a nice long powercurve even if it might have been alitle soft down low,but that was in a seriously worn out engine.

A friends Edelbrock RPM headed tunnelramed 383smallblock with that cam was perfectly tuned and was very mild manered all around,had a fairly tight 3000rpm converter,could idle forewer,started by just a very quick twist of the key,but standing still just slam the throtle wideopen and the thing would smoke its 28x10.5 ET-STreet tires for probably 200meters(thats about 1/8mile for you Americans) and go about 100km/h(about 60mph) when letting of,thats how a well tuned 500HP smallblock behaves when everything is set up right and ran mid to low 11s in the quartermile shifting at about 6000rpm.

Hey we all need more power and there is always tradeofs but rest asure that build it right and tune it just right and you can make something that is wild in most people books behave quite good on the street even if it wont idle like that stock 318,but its not for everyone,a real 500 horse engine will eat stock drivelineparts over time unless you run it on ice or never step on it,and it will show alitle attitude.

BTW how is that 100+ octane measured? I know that we have a way different measuring system up here in Sweden compared to the American system.

I'm Dutch and we have the same Octane-system as Sweden I think.
Our gasoline octane ratings go from 95 to 98, and a few locations sell 102.
Propane's octane rating varies, depending on how the mixture is done at the pump. Overhere, LPG is a mixture of Propane and Butane. I believe Summer/Winter blends have the ratio change from 40/60& to 60/40%.
So it's hard to put a definite octane number on LPG, but the general idea is that most folks think LPG has a rating of 100-104 octane.

Seeing how the 11.3:1 CR engine in my daily driver can run without any issues on LPG, tells me the octane-rating must be good.

I'm currently on the fence about either upgrading the 360 with heads and a cam, or focus my energy on rebuilding a 6.1 Hemi I have laying around.
The Hemi needs new pistons, machine work, and electrical work in the car. Oh, and probably custom welded headers.

In the end the 360 will be cheaper, quicker and easier to upgrade, but a 6.1 Hemi in a daily driven Dart should be fun either way.

Try a turbo. With a bone stock 318,(deck O-ringed with copper head gaskets), blowing through the 2bbl intake,(draw through system), with a 800 Thermoquad at 26lbs. of boost, 536hp&586 ftlbs.
I have since upgraded cam, heads, intake and gone to blowthrough so it needs less boost. I am hoping to have the motor bolted to the dyno this weekend.
I dynod the 318 with the stock 2bbl at the time, just advanced the cam a bunch to try to get some cylinder pressure. It made 160 hp. 1 hour later with the turbo 536 hp. It cost me less than a grand.

Hard to beat turbo-power I agree, but I don't like the plumbing involved.
Specially not in an A-body.
And I'm already at 210psi cranking compression with the 360ci.

A cam change would “cure”(?) that