Being a "grandpa" I tend to shift at 2000 Rpm for the best gas mileage. Being an old drag racer I did run her up to about 3500 Rpm soon after I got it. When accelerating on a highway ramp I'll bring her up to 2800 rpm. When it hits 200k I plan to change the timing gears to metal and plan to do the chevy I6 rocker install.
I have had a mounted vac gauge in most of my vehicles since the 70s. This gauge will help in diagnosing engine issues as well as saving gas.
The old stock exhaust system is kind of restrictive and will be changed out when the warmer weather hits.
The 300 is a truck engine that is probably the closest thing to a diesel in the way it builds power at low rpm. With 3.55 gears I find it a good compromise for my needs as a commuter/ work / and occasional hauler. I have had many I6s and the 300 has more torque and hp than all but a 706 Cid REO ( 5 ton Army 6x6) that I have driven.
At 60 mph I can get about 20 mpg. Mixed driving 16-17. On a 150 mile blast @ 75+mph dropped it down to 15mpg.
BTW back in the 70s an older gent had a Pontiac Tempest Sprint with an OHC 250 6 that was pretty impressive. He did change out the 250 block for a 292 and had exhaust cutouts for the drag strip. He used to embarass some of us V-8 boys. With 4.11s he would get revs up over 6000 grand IIRC and it sounded awesome.
Happy New Year
rikard

 

Rikard: I had a truck almost exactly like the one in your sig, but it was a LB. I agree that the 300 5spd & 3.55 gears made for a great all around truck. I got close to 20MPG on the 35 mile commute during the week, and still had plenty of pulling power for the weekend toy hauling duty.
My ex totaled it just shy of 50K (late 97), and I bought the 1980 to replace it. As much as I love my classic truck (I kept it, and got rid of the wife), I would really have preffered to kept the 94. I custom ordered it, since I couldn't find one speced like I wanted. Unfortunately, I had overlooked the Tach option somehow. The 80 really fits, now that I am officially a grandpa myself.......

As for spinning these big sixes to 3000 or higher, yeah they'll go that high, but I seldom see any need to exceed 2500. The higher you wind them up, the sooner they wear out. These engines can live for a very long time, as long as they are not abused. They'll work harder, at lower RPM, than most other engines. The odd part about that is, they will also get decent MPG when driven with restraint, loaded or empty. Wind them up, and the MPG goes away.

 

Yep, I suppose it is the big block effect. 4" bore and 3.98" stroke will really suck a lot of fuel.

Yes, you don't need to go over 2500 rpm unless you want to pass or get going really quick. Mostly over 2500 is for fun. However, pulling a trailer in the Rocky Mountains I had to run in the low 3000s up some grades--that or go really slow.

 

yeah mine doesnt really go high unless i want to you just dont need it in my opion but anyone have these motors to about 5 and a half? one day i was driving it with new floormats went from 2nd to 3 and it stuck spun the wheels in 3rd yeah i thought i tour sumthn up they wil scream at 5500 rpm great motors

 

There are members here who will take their 300s up to 5000 - 5500, but only breifly. Redline is relative. It will cruise all day at 3600 rpm, but at 5500 I suspect the engine would be in trouble in a short while if not a matter of minutes. Still I would not recommend going over 4000 and don't take mine over 3800.

For those of you who never go over 2000 rpm. Back in the 70s we used to be warne about buying an old car that a little old lady drove as the old lady never revved it and thus there was a step worn into the cylinder and when the hot shot kid bought the little old lady's car (or grandma's car) and floored it, he hit that step and broke a ring. Not sure it is a real problem anymore, but just a thought.

Sure wouldn't hurt to wind it out once a week or so even if you otherwise never rev it.

Now my wife's Aerostar (below) I wind out into the 5000s all the time. Kind of have to to get that little 3.0 to go anywhere.

 

haha yeah i dont get mine past 4 ussualy unless im messing around burnouts and what not but i ussually dont get it up there the 5500 the pedal stuck suprised me i didnt mess sumthing up but these 300s are reliable cant tear em up if you keep the oil changed my dads has just over 200k and when i say hard miles i mean he has driven it untill it quit from getting too hot when pulling a trailer or just driving and his rad. hose blew out i would never do that but it proves that these motors dont die change ur oil .....wow sorry for rambeling on there is nothing about a tach in all of that but hey once again at least its about the motor sorry again and thanks for letting me ramble on

 

In re: the above post. In regards to changing oil, one time I drained the old oil put the new filter on and forgot to add the new oil. Still did not kill it. That was one of those days were too many things were happenin at one itme.

 

tallpall, thats a good point. i have been stepping on the pedal more now that i got all this feedback. i dont think i got it over 3000 yet but anything over 2000 is high for me. i'm hardly ever in a hurry and i just take it easy. plus theres sooo much traffic in this area sometimes im lucky if i ever get past 2nd gear.

old rust bucket. thats crazy! im glad you didnt lock it up. how long did you run it with no oil?

 

I think I normally shift around 2500 rpm for regular driving. But what I noticed with this truck (my first EFI) is that there is a power surge at 2000 rpm that pretty much stays with it all the way up, so it's a lot more fun to get it above 2000. My carbed 300s didn't have that effect.

 

Dude.. you motor isn't supposed to go past 3,400 stock. O_O

I think one or more of the men on this site has a built six that goes past 6K.


I'm not the only one? Ha! I knew it. My dad jumped in my truck one time and revved the heck out of it( this was before I started really beating on the motor). Ole' Betsy surprised me - I had no idea she could sound that mean. She immediately died down to a low growl, as if she scared herself. This was with the stock exhaust. I was proud of her.



What are you geared? My truck never went much past 2k when I had 3.08's. Now it pretty much stays above 2K because of the lower gear swap.

 

6cylBill,

i forget what gears are on that truck. its a 95 4x4. i dont go above 2k rpm in overdrive until i hit 70mph. i know i can check the tag on the diff cover but ill have to wait til i get home to do that.

I agree that these engines sound really mean when they're revved up even with the stock exhaust but i cant wait until i get a flowmaster muffler on it. thats gonna sound awesome. and ill wonder how i got along without it just like every other upgrade i do to this truck

 

You probably have either 3.08 or 3.55, more likely 3.55. If so you should be revving past 2K I think, but I'm not sure. I've never had 3.55's.

You sound as if you have "the fever" too. It's been going around. I have it myself.

Ah to be a truck guy.

 

Mine has 3.08 w/ the 4 speed and it hits about 2500 at 60ish

 

What are your RPM's doing at 20MPH and 30?? 1100??

 

To be honest, I havent really looked.. I'll have to check that when the weather is a little better.