The new high compression 300 sees 3800rpm every day at least once as I get on the highway, that's 48mph in first gear and where it automatically shifts while floored. When the vacuum modulator let go, I didn't realize it at first and let it get to 4200rpm before I manually shifted it.
My 84 F250 had a full manual C6, and it sounded so awesome at higher RPMs that I would just let it wind out getting on the highway. It was still pulling a bit at 6000rpm, but I would shift it as I know these engines have a fairly long stroke. It did have a quality, properly set aftermarket tach and the rpms for a given speed were dead on with most calculators.
My 69 F250 had it's original stock 300 with 68,000miles when I got it. 4.10 gears and a C4 automatic, with 33" tires. RPM at 70 was 3000, and it would cruise there often. After I replaced the engine, I had to make a hurried trip from Bremerton to Vancouver WA. My peak sustained speed was around 90mph at just under 4000rpm for about 35 miles south of Olympia. At that speed I was getting some misfiring as the points were worn, afterwards I replaced the points distributor with the HEI distributor I had on the 84's engine and had no more issues. I sold that engine about two years later to a guy on Craigslist to replace his knocking 300.
If your engine is having trouble getting over 3000rpm, something is seriously wrong with it.

 

I didn't mean to sound like a dick, just wondering really. Your experiences with the big six just seem a bit different to most people's. In stock form, these just aren't high-rev racecar mills (no pickup engine is), they are tractor engines. The inline six design itself doesn't lend itself to high rpm performance as easily as a V-8 or V-6, but makes up for it in torque.
Might just be that I feel that running my engine that fast is a whole lot more wear and potential for damage, than is worth the extra speed.

 

I can get a 300 to turn 4000 in stock form no problom.

1)Why? It aint making any power above about 2800 anyways.
2)Why would I want to do 48mph in first? Am I 16? Am I making up for other things I lack?
3)Not only is everything you described a complete waste of gas. It is quite probobly illegal due to noise violations, and terribly hard on engines of any kind.


I dont frag on a 302 like this, and that engine has power in the range you just stated. You are down right idiotic for treating a engine of any sort like this and have given what I consider to be the downright worst advice I have ever seen on this forum here today. The stock shift point is all the proof I need, on a C4 or C6. That is somewhere in the 1800-2400rpm range depending on loading.

No way in heck is this engine supposed to turn those RPMs, nor any engine in normal use.

This is questionable as to your competence as a mechanic. Let alone your common sense.

 

This engine can be tuned and modified to build power up to about 3500 with cams and flow improvements. You can turn a clean 250HP out of this motor it is just prohibitivly expensive. A aftermarket exhaust and intake with a small 4bbl will give one about a 50 HP/60ftlbs boost. even with stock internals. That makes it into about 180HP and 300ftlbs of torque from the 300. Porting polishing and a higher CR will give you another 20-30HP and 30-50ftlbs. assuming you have the carb and cam setup properly.

 

Fine, you want to be that way be that way. I am a far more competent mechanic than you, and I have a bit of a clue what I'm talking about. I have built my own engines, several times over, and not just 300s. I don't just cruise around looking at hot rodding articles and internet forums and BS my way along, I have actually done this stuff. That is what got me to where I am today.
Because you do not provide proof to back up your claims, I feel that speaks volumes to your competence and experience.
BTW, I have had two high RPM engine failures, neither a 300: The first was a 390 that broke a motor mount and stuck the throttle. It shot to 6500, dropped a valve, and split a bore. The second was a 2.3, which popped a rocker out at 5200, but then that was actually the fault of a plugged oil passage in the cam. I pushed the rocker back in place, fired it up and limped it home.

 

Hey Einstein, I am an industrial mechanic. I dont get any magazine subscriptions at all and I only belong to this forum. I have built my own engines.

What are you a profesional forum moderator. You treat your vehicles like a damn 16yearold with a stiffie and too many pixie sticks in the system. I am done arguing this with you as any words to convey the great level of stupidy you are professsing here would get one in trouble.

 

thats funny as hell but the way i look at it if you can fix it and its yours why not? i take it easy on an older high mile motor but a good tight motor i thrash on them all the time and love every second of it.

 

When you buy my van, you can drive it the way you want. Until then, when i pull out at the intersection in the freeway (not an on-ramp), I will floor it to keep from being run over. I don't use the floor as my cruise control, I don't wind it out for every shift, and none of that involves you in any way.
I like the proof you provide to counter my claims. Look over my posts here, look at the things I have done, and tell me I don't know what I'm doing. What you have argued so far does normally get people in trouble, but i have a thick skin. Keep it up and I may get tired of it.
Provide me proof that a 300 cannot handle the RPMs I have stated and I will take it all back and apologize. Until then, you have no right to say what I do to my own vehicle is stupid.

 

Let's be more civil, please! We've been here long enough to know each other well enough to know we're all decent guys.

Flip is a good guy and so is Jared.

By the way, I revved mine to 4,000 rpm today. It was an accident. I forgot had my transmission in 1st gear. I got to 30 mph when I realized my transmission wasn't shifting. When I looked at my tach I nearly pooped.

 

Stock 300s will run to 4,000 RPM no problem, but they don't like it. My engine is a stock EFI 300 in a 1996 F-150 with 305,000 miles, and it has never liked running above 3,500 RPM. It most certainly won't blow up, but in stock form it just doesn't make much power at higher RPM. I have had it to 4,500 RPM a few times in it's life, but it was a futile gesture. I do know that if intake and exhaust upgrades are performed (especially for you carby guys) and port/polish work is done along with a mild cam upgrade, they'll wake up and willingly spin 5,000 RPM with stock valve-train components. I'd be concerned about more than that, but not ripping my hair out with worry. I personally prefer the low RPM grunt of the 300 in it's stock configuration, so I won't mess with mine. On another note, since several of you have copped to running a C6, what stall speed are you running on your converter? I would like to get about 1,800 RPM stall speed, since torque peaks at 2,000. When I do my 4wd conversion, I might put a C6 in.

 

The stall in my van is stock, about 1200 stock/1400 as the engine is done up now.
My F250 had an 1800 stall converter, and I doubt that I would go that high again as there is a lot of low end grunt available before the torque peak that you are missing out on. It also builds a lot more heat in the transmission. It's really only good for drag racing or if you have an engine that makes it's power a lot further up in the RPMs so you don't bog it down.
Your stall speed will vary depending on power produced as well.

 

I had thought so. A long time ago when I first got my truck, the original owner had destroyed the M5OD. Now I know they have a reputation for being less than robust, but the truck had less than 1,000 miles on it. The p/o was having a mid-life crisis, and had to buy a truck. So he bought a high GVW 1/2 ton and wondered why it rode like a tank. He also never drove stick, and destroyed the tranny and clutch (and flywheel) in that brief amount of time. Before I got my NP-435, I used a C6 for a while. I never liked it because even though I had a large diameter converter, it stalled at 2,000 RPM. When it comes to most things mechanical and electrical I am on top of it, but I do not really understand automatics. I thought a large diameter converter would have a low stall. What can I do to ensure that I have a low stall the next go around? Can I request a trans shop build the converter for a 1,200-1,400 stall?

 

1969 F250 300 T18 LT235/85R16

I ran 50mph @ 2500rpm on my way in to work this morning, I pushed it to about 58mph/2800rpm down a hill and it sounded like it was ready to explode, but I haven't gotten mine running good.

 

Stall is a result of the distance between the vanes inside the torque converter. The closer the sections are, the lower the stall speed. A low stall speed also will help with efficiency going down the road since overall the torque converter is tighter.
You can get them made to whatever stall speed you want, but you will need to provide some pretty detailed info on the engine's power and torque. Usually a printout from a dyno is needed.

 

i think most of its based on your cam and where it makes good power (power band). if the cam is stock than a stock converter is all thats needed. my 302 has a .512 cam and highly recommends a 2500 stall but thats for a high reving sbf (6000 rpms)