New 440 combo in the works !

[Clyde9]

From: ZR91  (Original Message)
Sent: 4/23/2008 10:34 PM

Well,
after much research I have decided to try something different for the MoHo this year.

But, before I do, I thought I should ask your opinions!

1) I have been advised by Comp cams to NOT change my rear gears from 4.10 to anything lower numerically-3.73/3.42, etc, because there is no cam that can create the torque required to move an 11,000 pound motor home at lower rpm's.They swear it will just lug the motor and make it use more fuel.
-They recommended changing the cam instead to an XE 262, part # 21-222-4, as well as the timing chain and gears.

2) I talked at length with Edelbrock about their carbs, and they feel that with the lower rpm range of the MoHo that I should change my 750cfm Edelbrock carb part #1411-to a 600 cfm carb part #1406. Apparently the 600 cfm carb will give me better fuel economy as the smaller bores will increase the air velocity and fuel atomization, up until to 4,000 rpm (which I never get to anyway)

This all sounds good, and the parts are very inexpensive to do this.
I just need some feedback from those of you with actual experience with these parts.

Thank-you,

Jay



From: bluebird5750
Sent: 4/24/2008 12:19 AM

Before changing cams to get better fuel economy, do lots of research. When you increase duration on the camshaft, you raise the power band to a higher level. You do increase the output of the engine, but you also raise the power band  to a higher rpm. Where does your mh like to run at right now? Changing the carb will also have a effect on power. Going to a 600 carb on a 440? You will be losing 150 cubic ft of  air per minute at wot, that's a lot. Consider your engine an air pump, because that's what it is. You just add fuel to keep it pumping air. Take away the air and you loose power. I am sure there are some mopar sites on the net. Find them and ask some of the guys that race, and see how they setup their tow vehicles. I'm a gm guy, and if I were building am engine for my mh I'd go with a cam with no more than 215 or 220 degrees of duration@ .050 valve lift. When building an engine for economy you have to build it for the torque curve it runs in. Similar to what the factory did, but they built them for many different drivers. The mid 70s were built a little on the lean side for emissions control. you may get better millage by riching up the carb a little, and increasing the timing just a tad.

Chuck



From: ZR91
Sent: 4/24/2008 10:25 PM

Thank-you for the input.

The duration on the cam they recommend is exactly the duration that you suggested.

This cam (on their dyno) apparently raises the torque to 410 at 2000 rpm, and a solid 525 + between 2800-3200 rpm.

The torque is what I am after, especially when we start pulling the boat.

I will do a complete pictorial of the teardown and install, and post results, just in case anyone is truly hard up for entertainment...

Did I mention that I just bought a powerdyne supercharger?

I know-one step at a time...



From: WestcoastRedneck5
Sent: 5/4/2008 1:21 PM


.I have the 440-3 with the750 edelbrock.Very happy with it lots of power & I need it pulling my 3000 lb boat up logging roads.Highway I get 12-14 mpg which actually is pretty good.I think a must is 3 inch dual exhaust with flowmasters.Sounds great to.