[erbssr]

Got a 289 running C-4 & 4;11 rear gears. At 65mph it's turning about 3000 rpm. Anything wrong with long trips at that kind of rpm? I know it will burn lots of gas. LOL

 

[galaxiex]

Nothing "wrong" with it, no... but the high revs and noise, well....

I've done a medium long trip in a 68 Mustang 428 4spd with 3.91 gears and short little 14" 60 series tires.
About 3200 rpm at 60 mph.
It didn't hurt the engine... but....

It gets old REALLY FAST... and the horrible fuel consumption and noise was a killer. Never again!

After that trip I immediately got a set of 3.25 gears. Much better! and the big block still moved the car really well.

The next long trip with the 3.25 gear was MUCH nicer and it even pulled down 18-20 mpg!

YMMV

 

[erbssr]

I'm just buying the car & have to drive it home 272 miles, so I guess I can put up with it. It has sound deadening mat under the carpet. Don't want to change the rear gears since I don't plan on long trips, plus I wanna take it out to the local dragstrip next Spring. LOL

 

[galaxiex]

Well, you could always cruise home in the slow lane....

50 mph would be ok.
Not much fun but would save a ton in fuel, and maybe your sanity.

 

[erbssr]

For sure. Thanks for the reply on the rpm. I didn't see a problem but the guy I'm buying from said he wouldn't do it.

 

[gtaroger]

My Falcon is running 4.11 gears with a 302. I have driven it on trips of 50 miles each way. Sucked the gas up and drove me nuts with flowmasters. I installed a AOD trans and went with Magnaflow mufflers.Long trips are do able now. Still not great gas milage ,but that has alot to do with the big cam and racing carb. It still is much better now.

 

[erbssr]

My Falcon is running 4.11 gears with a 302. I have driven it on trips of 50 miles each way. Sucked the gas up and drove me nuts with flowmasters. I installed a AOD trans and went with Magnaflow mufflers.Long trips are do able now. Still not great gas milage ,but that has alot to do with the big cam and racing carb. It still is much better now.

Well, we will find out tomorrow, how bad it is. It has a mild cam, long tube headers, & Flowmasters

 

[galaxiex]

Ya, I’m gonna guess those flowmasters are gonna drive you nuts.
Probably will have to try find a cruise rpm where they don’t drone too bad.
And they are gonna drone...

 

[extech]

does it come with the flowmaster decal in the window?

 

[gtaroger]

I found there wasn't a rpm where they didn't drone.If it was high enough to not drone, it was blowing me out of the car.My pipes dump out in front of the rear wheels. The flowmasters than were on my car were the single chamber. They were the loudest mufflers iv'e ever had on any of my cars. My 74 Bronco had flowmasters on it when I bought it.I went up north deer hunting with it They droned like hell between 2000 and 3000 rpm. When I got back I had them taken off.I went with Magnaflows on it also. WhenI nailed it it get loud but at idle and cruise speed it's livable . No droning at any speed.

 

[n2omike]

Got a 289 running C-4 & 4;11 rear gears. At 65mph it's turning about 3000 rpm. Anything wrong with long trips at that kind of rpm? I know it will burn lots of gas. LOL

Some general advice for more than the original poster:

Hard to beat a 3.25 gear if you're going to travel at 65 mph very much at all. That's what I ran in the mustang while driving it back and forth to college 100 miles each way... and on 5 hour trips each way during the summers to Baltimore. Still had plenty of zip, and could actually keep up with traffic without making you cringe.

You can still keep a 4.11 for 'special occasions' as it can be really fun in town or if you want to go racing. A couple things to look out for in case you want to swap back and forth and/or not have to change driveshafts...
1. Make sure each rear is set up for the same spline axles. (28 vs 31 spline) It is probably 28.
2. The rear end YOKE. These came in four versions. Short and long length... and wide or narrow U-joint. They came in every variation... Short/wide. Short/narrow. Long/wide. Long/narrow. You'll want to have the same yoke for compatibility.

I've had my car since age 15, and I'm 52 now. It was my daily driver for YEARS. I've had more engines, transmissions and rear ends in the car than I care to count... especially rear ends in both 8" and 9". I've used the following ratios (pretty much all of them) on the street and strip, and really like the 3.25 for overall street use on street tires. 2.80, 3.00, 3.25, 3.40, 3.50, 3.55, 3.70, 3.89, 4.11, 4.30, 4.33, 4.57 and 4.86.

So my recommendation from real life experience is the 3.25 for a street engine built to shift at around 6000-6300 rpm with either a stick shift or mild converter and no overdrive. A more 'race' engine designed to be shifted at around 7k rpm and/or a 4k+ stall converter will gravitate more toward the steeper gear.

It's also my experience that Flowdisaster mufflers can sound cool, but don't flow all that well, and will drive you absolutely nuts with their droning.

Good Luck!

 

[galaxiex]

Yep, 3.25 is an excellent street gear.

 

[gtaroger]

I ran a 3.27 gear in my last car and it was great. I had AOD and it dropped the rpms real low on the freeway.I got 22 mpg at 70 to 75 mph. Got great street performance to. Car weighted 2400 lbs.Worked real good for trips and still ran strong on the street.