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Old 10-25-2013, 03:50 PM   #16
concours
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This thread reads like an old J.C.Whitney catalog... "more power" "faster passing" "lower ET" "higher top end" "stronger mid range" "better MPG" "cooler running" "deep, mellow sound"
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Old 10-25-2013, 04:43 PM   #17
Baroquenride
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Originally Posted by broncobowsher View Post
so true! But as originally stated, doesn't care.

Getting the right mix and good atomization are needed for best power, best economy, and actually do a pretty good job at running clean emissions as well. The 2-barrel can be good. A 4-barrel generally can be better. The trick is actually getting it tuned right. I know a lot of people who can tune so it runs good, but when checked with a good wide band exhaust sensor they are always off. Tune with a wide band and it gets better. More safe power on less gas.

You may want to try that with the stock 2-barrel carb first. Many heavy duty applications were set to stupid rich for "engine cooling" under heavy loads. That is if the stock 2-barrel isn't wore out already. Sloppy throttle shafts, melted boosters, delt with lots of this crap. Time for new carb, might as well make it a 4-barrel.

Good rv cam and sufficient exhaust are also good upgrades.
+1
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Old 10-26-2013, 07:01 AM   #18
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One more time, the 2bl carb is NOT the restriction limiting horsepower (at these "working engine", NOT racing speeds). A cam (the right one) would most definitely help, but combustion chamber design is also a limiting factor. The dual exhaust thing is also waaaay overblown, (again at working truck revs) Someone mentioned timing advance curve... VERY relevant to power output AND economy, but with a FULLY LOADED motorhome, the conditions for engine destroying detonation would be very close at hand. It would have to be very carefully monitored. Knock sensors on modern engines have helped us forget about this once serious danger. A lightly loaded passenger car gives more leeway.

Summary, you could spend $2000 and 20 hours in mods, and have 3 more HP.
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Old 10-26-2013, 08:20 AM   #19
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Originally Posted by concours View Post
One more time, the 2bl carb is NOT the restriction limiting horsepower (at these "working engine", NOT racing) speeds. A cam (the right one) would most definitely help, but combustion chamber design is also a limiting factor. The dual exhaust thing is also waaaay overblown, (again at working truck revs) Someone mentioned timing advance curve... VERY relevant to power output AND economy, but with a FULLY LOADED motorhome, the conditions for engine destroying detonation would be very close at hand. It would have to be very carefully monitored. Knock sensors on modern engines have helped us forget about this once serious danger. A lightly loaded passenger car gives more leeway.

Summary, you could spend $2000 and 20 hours in mods, and have 3 more HP.
+1

Its the heads and low compression pistons in that 360 that are the road block. The heads have small valves and very restrictive ports.

You could put the biggest bumpstick, a 1150 CFM double pumper and dual 3" exhaust on that tired LA series 360 and maybe notice a tiny improvement.



The OP would be better off saving up some coin and getting a 360 crate motor from Mopar Performance.
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Old 10-26-2013, 11:28 AM   #20
Baroquenride
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Originally Posted by concours View Post
One more time, the 2bl carb is NOT the restriction limiting horsepower (at these "working engine", NOT racing) speeds. A cam (the right one) would most definitely help, but combustion chamber design is also a limiting factor. The dual exhaust thing is also waaaay overblown, (again at working truck revs) Someone mentioned timing advance curve... VERY relevant to power output AND economy, but with a FULLY LOADED motorhome, the conditions for engine destroying detonation would be very close at hand. It would have to be very carefully monitored. Knock sensors on modern engines have helped us forget about this once serious danger. A lightly loaded passenger car gives more leeway.

Summary, you could spend $2000 and 20 hours in mods, and have 3 more HP.
You're absolutely right. In my previous post I was thinking he was asking for better fuel economy and depending on driving habits and type of carb etc, could be obtained with a 4bbl. However, in re-reading the original question, that wasn't what he was looking for.
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Old 10-26-2013, 05:05 PM   #21
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I concur with Concours. He is absolutely correct.

If you want to toss money at it, spend it on the things that will actually make a difference such as a new ignition system. Or possibly buy a new replacement carburetor after a professional inspection of the original one, I suspect there are probably many age and wear issues such as a worn throttle shaft, etc that could benefit your performance by getting repaired.
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Old 10-26-2013, 07:35 PM   #22
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I agree with Red83GT(in normal circumstances), camshaft with the Edlebrock intake/carb combo may wake it up, right in the low to mid rpm range where it is needed. You should see a slight increase in mileage with the right camshaft due to not having to have the throttle opened as much to go . When a motor isn't struggling as much you don't need to constantly be giving it more gas to keep up with traffic, so less gas used.
I'd call Edlebrock tech line and they will set you up with the parts that compliment each other . Maybe even their EFI setup ??? , maybe not worth it right from the start, I haven't done much mods on mopar so whether they take to these additions I can't say. I do know some areas that 2 holers have given the best running and economy with good tuning. Maybe that crate motor would be best, but not really worth the coin.
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Old 10-27-2013, 07:06 AM   #23
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Thanks for all great advice guys. I was told my existing carb is worn out and needs to be replaced. I thought if I was going to replace it anyway way not go bigger. I will probably just try to find a replacement 2 barrel and see how she runs. I'm not dumping a ton of cash into it. Most of the time it's a storage shed for bike parts anyway.
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Old 10-27-2013, 08:42 AM   #24
concours
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Thanks for all great advice guys. I was told my existing carb is worn out and needs to be replaced. I thought if I was going to replace it anyway way not go bigger. I will probably just try to find a replacement 2 barrel and see how she runs. I'm not dumping a ton of cash into it. Most of the time it's a storage shed for bike parts anyway.
How many miles total? Motorhomes usually don't get 100,000's of thousands of miles. If the throttle shaft bore in the body isn't sloppy (quick manual wiggle test) then a gasket/rubber parts kit could restore performance. I'm old, and "rebuild kit" in carbs was a common thing, most times now, though, R&R is the ($$$!!!) order of the day.
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Old 10-27-2013, 01:49 PM   #25
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Changing to a four barrel would be a lateral move. That 2 bbl flows all the air/fuel that engine needs at the speeds it's being used at.

Many, many myths stated above. Spend the money on beer/fuel.
Agreed your stock 2v should flow about near optimum. If you do go with a 4v swap keep it within usable range. I'd suspect 400-500 CFM is what a 360 could likely use. Just don't go monster 4v carb the racers use. Just stuffing more air and fuel in the motor doesn't gain you anything unless you've got the internals(cam, valve train) to handle more volume. Big honker carbs w/o other mods for street use generally don't gain you much other than "I'm running a 4 barrel" bar stool bragging rights and the cool sound when the back barrels kick in. Sounds cool but doesn't mean you're really going faster as to the guy with the correctly set up 2v who just passed you will remind you of at the end of the run.
Do your homework before buying parts.
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Old 10-27-2013, 05:08 PM   #26
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I can tell you I could tell the difference between a 4 barrel only running on 2 and running on 4. Hint, when putting the hose clamp on make sure the tail doesn't press up against the secondary shaft holding it shut. That little 302 ran noticeably better on 4 instead of 2.

About 18 years ago I was working on a 440 powered Class A Winnie. At one point I was standing over the engine as it was being driven around town. Really cool watching the white cloud of fuel vapor pouring out the venturi boosters. Probably not the smartest thing straddling a big block V8 at full power, but a really cool sight I still vividly remember.
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