rpm

[81f100]

how many rpm does the 300 turn ive heard it runs out of rev at around 4500 rpm

[powerjunkie]

efi or carb? stock or modified?

[300 HIPO]

I think the max HP is produce at 4,500

so I would guess you would never want to go over 5,000 or 5,500. its engine is probadly not doing much anyways over 4,500 to 5,000

[Luckyman]

in stock form 4500 max but after 3000-3500 all you are making is noise.

[81f100]

this one is carb and is stock except for a hedman hedder since my stock manifold came off the truck in four or more peices to say it was running rich was an understatement

[300 HIPO]

This is all good info..I would have never thought it was all below 3,000..I love these 300's..I want one in all my cars.

[81f100]

what can i do to get more rpm out of the motor

and what is the most effiecent power adder s/c turbo or bottle

[Lazy JW]

I think the max HP is produce at 4,500....

Bone stock max is at about 3500. You have to improve the breathing significantly to make much more power above 3500. Fortunately, this is not difficult.

Do some reading in the FAQ's and searches of past posts, then you will be able to ask more questions.
Have fun,
Joe

[FlareSide]

Hp: 145 @ 3,400

Tq: 260 @ 2,000

Not exact. But close enough.

By the way, making a 300 turn more rpm is silly. It's a low revving motor. More rpm doesn't mean more power. In this case, it means broken parts.

[Lazy JW]

....

By the way, making a 300 turn more rpm is silly. It's a low revving motor. More rpm doesn't mean more power. In this case, it means broken parts.

That will be news to 6re6 (The Frenchtown Flyer).
Joe

[Harte3]

I'm silly . Mine pulls hard to 5000 in 2nd. Pulls hard to 4500+ in 3rd but at 75 mph and 4500 rpm in 3rd I am border line "bear bait" in a 70 mph state. Yes, I do indulge the "child" every once in a while.

[FlareSide]

....

By the way, making a 300 turn more rpm is silly. It's a low revving motor. More rpm doesn't mean more power. In this case, it means broken parts.

That will be news to 6re6 (The Frenchtown Flyer).
Joe

If a 300 makes 140 horse at 3K, why would it make more power just because it turns 6K? There's no power up there. Nothing but noise.

[powerjunkie]

oh FTF, please say something!

[The Plankster Prankster]

can't say i've ever been past 4000 in mine.
as for FTF, his are built to breathe so much better than our stock motors, which allows him to produce power at greater speeds.
last i checked, i can run WOT up to about 4000 and just hang out there till i feel like shifting. i don't do that, but it really won't get above it, just can't breathe enough

[wallaka]

....

By the way, making a 300 turn more rpm is silly. It's a low revving motor. More rpm doesn't mean more power. In this case, it means broken parts.

That will be news to 6re6 (The Frenchtown Flyer).
Joe

If a 300 makes 140 horse at 3K, why would it make more power just because it turns 6K? There's no power up there. Nothing but noise.

HP = rpm x torque/5252

I'm sure you see how that works out if you can keep the torque up with sufficient airflow

[willowbilly3]

Run this through the rpm calculator. 100 mph, 3rd gear on a T18, 3.73 gear and 31" tall tire. Done that. Gotta be 6 grand I'm thinking.

[Lazy JW]

....

If a 300 makes 140 horse at 3K, why would it make more power just because it turns 6K? There's no power up there. Nothing but noise.

This principle is the very heart and soul of hotrodding; has been for a great many years now ever since two young fellows lined beside each other in their Model T's and said "Let's Race!"

Longer duration cams with higher lift coupled with proper porting, bigger carburetors, free-flowing exhaust, etc. allow an engine to maintain volumetric efficiency at higher speeds, hence higher horsepower as per the formula stated above. It really does work.

That said, in stock form it truly is silly to rev a 300 much over about 4000 rpm.
Joe

[StrangeRanger]

Run this through the rpm calculator. 100 mph, 3rd gear on a T18, 3.73 gear and 31" tall tire. Done that. Gotta be 6 grand I'm thinking.

Figure those tires at 680 revs/mile so with a 1.69:1 3rd gear you're turning:

680 x 3.73 x 1.69 x 100/60 = 7144

Which is just plain abusive for no purpose whatsoever.

[willowbilly3]

Don't be too quick to judge, you weren't there. Smart? no, Justified? probably not. Would I do it again? maybe.

[American Thunder]

If a 300 makes 140 horse at 3K, why would it make more power just because it turns 6K? There's no power up there. Nothing but noise.

In stock form, it is pointless.

But if you get the induction and exhaust system flowing more air, then the air pump (the motor) will want to rev higher and make more power doing it. I don't rev my stocker 300 beyond 3000 rpm, but my 302 stroker doesnt even start making decent power until 4500, and idles really rough at 1300. If I built up the 300 similarly, it would pull like heck past 4500, too.
(Of course it would, it's a Ford)

[Lazy JW]

I wish I could say I never did anything stupid but I would be lying
Joe

[81f100]

when i do build mine will i need to put stronger valve springs in it to hold the more rpm's????

[American Thunder]

when i do build mine will i need to put stronger valve springs in it to hold the more rpm's????

Whenever you buy a camshaft with longer duration and more lift, you should also buy a new set of valve springs matched to the cam.

[4x4xFORD]

What everybody else has been saying... Hotrodding is hotrodding, whether it be a bent 8 or a straight 6. More airflow equals more power, just at higher RPM's ..........

[80broncoman]

Run this through the rpm calculator. 100 mph, 3rd gear on a T18, 3.73 gear and 31" tall tire. Done that. Gotta be 6 grand I'm thinking.

Figure those tires at 680 revs/mile so with a 1.69:1 3rd gear you're turning:

680 x 3.73 x 1.69 x 100/60 = 7144

Which is just plain abusive for no purpose whatsoever.

I'm about to call BS on that. NO not the math. just on the fact a stock 300 made it to 7100rpm ??

[Lazy JW]

Methinks the valve train "may" have issues somewhere south of 7100 rpm (valve float, anyone?)

[mutt]

jeez- ive yet to take The Senator (big, white, empty, & expensive to keep around) above 3700. Thats WITH my mods. Power falls off, its straining.....but Im very conservative with my gear.
Theres nothing to gain at 4k, the bull wakes up 2100-3, tho it pulls at 1200.
With the headwork, ex, & 2bbl, I had more power up here, to a noticeable degree.
But revvin the sturdy beast past 4k? nah.....im too cheap.

[TCIC 300ci superbeast]

Methinks the valve train "may" have issues somewhere south of 7100 rpm (valve float, anyone?)

my old 300 with only 80,000 on it would float the valves at 4750rpms i really dont see it hiting 7000.
i dont even think that if you were doing 4000prms in forth and then shifted down in to 3 or 2 that it could over rev to 7000

[American Thunder]

Stock hydraulic lifters pump up and float the valves over 6500, generally, even with heavy valve springs installed.

Which reminds me. I found an old operator's manual for a 300 industrial motor. It lists valve lash adjustments, and I'm wondering, do some of the 300 industrial engines have solid lifter cams??

[mutt]

It lists valve lash adjustments, and I'm wondering, do some of the 300 industrial engines have solid lifter cams??

YES! Are there?? That would be a very nice upgrade.
Ive spent many a pleasant time setting valve lash, & i like the sewing machine sound of properly adjusted solids.......of course, thats on rigs with proper rocker arms- 50's Chev/Jimmys, and slant 6's. IIRC- the stamped steel pivot ball setup might e harder unless the contact patch is easily acessible.....cam gears, solid lifters- Back to the Future!

[StrangeRanger]

Was it an actual lash adjustment or was it just the rocker arm setup check dimension for late model 300s with the pedestal rockers where Ford specifies the rocker to valve stem lash with the hydraulic lifter completely compressed as .150" ± .025"?

[THE FRENCHTOWN FLYER]

in stock form 4500 max but after 3000-3500 all you are making is noise.

What luckyman says. Try putting a puny 1V and single exhaust on a 5.0 Mustang and see how it doesn't rev.

[83F150]

I held my 96 in 1st one time (automatic) and popped it to second at 5000rpm, to see if it acclerated any faster.

Mine shifts automatically at 3800RPM, suprising enough it actually felt like it was still pulling at 4500-5000rpm. But it sounded like it was gonna blow apart.

later,
Dustin

[rhetor]

This is my old motor, had mildly ported head, RV cam, 1.7:1 roller rockers, and 2.5" exhaust. 1995 EFI motor.

The head just will not flow anything above 4000rpm. If you put a circle track racing cam in it, you'd probably still peak hp at 4000rpm.

EDIT: just to clarify, the big red line is the tq curve. The dyno printed the line behind a bunch of numbers, as they weren't used to motors that peaked at 1500rpm! There was actually a slight lean spot at about 2200rpm, where the motor peaked torque by about 10-15ft.lbs. 19lb injectors and AFPR fixed that issue later on. You can see how the first pull was started at almost 2000rpm, then lower, then lower. This is because the dyno operator kept saying "what the heck? Its already flat!" I told him to start it at idle, he didn't believe me!

[American Thunder]

On Dyno2000 software:


Stock 300


300 I'm going to build


Pretty hairy 300+ hp 300

[rhetor]

You'll have to believe me on this one- It's all in the head.

Compare any decently performing 400" v8 intake port to the 300's intake port. They are double the size.

The big valves you put into the simulator are essential, as well as the much, much better flow necessary for the 300hp.

300hp is most definitely attainable, it just takes headwork. The intake manifolds, at least the EFI aren't really too bad, the runners are dastardly long, but could be shortened a couple inches pretty easily.

Its just the head. This is true with most motors. Your bottom line is your displacement and headflow.

[American Thunder]

That was my catchphrase back when I did a lot of performance engine work.
"Horsepower - it's all in your head."


P.S. As much as I love the 302s, a 300hp 300 would beat down a 300hp 302. I wouldnt be surprised if it beat a 300hp 351W, too.

[StrangeRanger]

Those "dastardly long" runners are tuned promote high volumetric efficiency at low RPM. Remember it's a dry flow intake. There's no gasoline to settle out and cause problems, just air.

[American Thunder]

Oh yeah, and the 300 from heck. Like to rev it??

[StrangeRanger]

How are you going to squeeze a 2.23/1.78 valve pair into the head? The valve stems are only about 1.91" center to center (tape measure, no caliper handy)

Other than that, I want one.

[THE FRENCHTOWN FLYER]

The valve stems are only about 1.91" center to center (tape measure, no caliper handy)

On a canted valve Boss head?

Also, on my crossflow head I moved the valve guides.

[American Thunder]

The valve stems are only about 1.91" center to center (tape measure, no caliper handy)

On a canted valve Boss head?

Also, on my crossflow head I moved the valve guides.

Ah, that's exactly the model I used in the program. Aluminum motorsport BOSS 302 heads, (with improved exhaust ports, which are far better flowing than the factory iron Boss 302 heads)
The 1969 Boss had the 2.23" intake valve, whereas, the 1970 Boss "only" had a 2.19" intake.

p.s. like my simulation 300's volumetric efficiency?? hah

[rhetor]

Those "dastardly long" runners are tuned promote high volumetric efficiency at low RPM. Remember it's a dry flow intake. There's no gasoline to settle out and cause problems, just air.

Yep. I would assume anyone going for higher rpm/hp would want to either widen up or shorten up those ports for an optimal configuration.

Those tuned intake runners worked great for my build! low rpm torque all over the place!

[J.R.]

American Thunder wrote: "I wouldn't be surprised if it beat a 300hp 351W, too."

Much as I like the BB6, I'd still put any money I was bettin' on the 351W. The
factory's '69 351W 4bbl rating was 290hp & 385lb/ft. Thus equipped, my stock Fairlane 500 station wagon would top 130 mph easily(in Nevada, of course), with roof rack load tied securely in place. And the wagons only got a single exhaust!

Now if you set rev limiters at 2500rpm, the BB6 would drag the Windsor backwards!


J.R.
SoCal

[300Straightsix]

that is the gross rated power

[J.R.]

that is the gross rated power

AFAIK that's the the same power shown on a dyno's "flywheel" horsepower & torque ratings also(assuming accurate instrumentation & honest dyno technician!). Net figures would be when all the accessory drives & full exhaust system are in place, again assuming accuracy & honesty.

But American Thunder was comparing the hypothetical 300hp/300lb/ft/300 inch six to a hypothetical 300hp 351 Windsor. Sounded like both were dyno ratings to me, i.e. 'gross' power ratings. Through the same type drivetrain, on the same vehicle, any vehicles would be relying on actual power to the drivewheels, not 'gross' or 'net' ratings. Anyhow that's my understanding of the ratings differences.

As has been mentioned before, manufacturers have sometimes been known to fudge the ratings they publish, both in hp or torque peak ratings, as well as the RPMs at which those peak figures occur. Even with honest ratings there still is the question of the RPM spread over which HP or torque near the peak ratings is actually delivered.

A few years back, with the '69 Fairlane's 351W engine & chassis slightly modified, I was on the tail of a friend's Ferrari, all the way through the 10 miles of uphill twisties & straight-aways to a mountain community where we both lived. He said was running flat outall the way, mostly in lower gears even in the straights because any upshifts would have slowed him down too much due to the narrow-RPM band of good torque capacity, whereas the 351W, even observing a redline of only 6000RPM, had a modded 3-speed automatic(maximums: 60mph 1st gear, 100mph in 2nd, & c.140mph in 3rd, the latter on level ground) that could utilize the Windsor's much broader torque range, coupled with the torque converter's changing ratios. He actually slowed me down going through & coming out of the tight corners. The Ferrari's lack of torque again(and the Fairlane wagon's near 50/50 front/rear weight balance). Interesting, but surprising experiment for both of us, to say the least.

The stock 300" BB6 similarly has a useful, but fairly narrow RPM range, at which it delivers close to its maximum torque. Swapping to a longer duration cam would kill off some of the engine's low RPM torque, in exchange for a producing a little more, higher up in the mid-RPM range, as well as more horsepower up there. That might be the way to go if the hypothetical "triple-300" BB6 was mated to a tight 5 or 6-speed automatic trans. Hope to find out

J.R.
SoCal

[willowbilly3]

Run this through the rpm calculator. 100 mph, 3rd gear on a T18, 3.73 gear and 31" tall tire. Done that. Gotta be 6 grand I'm thinking.

Figure those tires at 680 revs/mile so with a 1.69:1 3rd gear you're turning:

680 x 3.73 x 1.69 x 100/60 = 7144

Which is just plain abusive for no purpose whatsoever.

I'm about to call BS on that. NO not the math. just on the fact a stock 300 made it to 7100rpm ??

I never checked the speedo calibration at that speed, lol, but at legal speeds it was real close. That was with a ported head and a modified carb, 260 comp cam. Stock but port matched manifolds.
And the engine was hand built by a friend who usually only did race engines, totally blueprinted just like every engine he did. not quite stock.

[American Thunder]

The stock 300" BB6 similarly has a useful, but fairly narrow RPM range, at which it delivers close to its maximum torque. Swapping to a longer duration cam would kill off some of the engine's low RPM torque, in exchange for a producing a little more, higher up in the mid-RPM range, as well as more horsepower up there. That might be the way to go if the hypothetical "triple-300" BB6 was mated to a tight 5 or 6-speed automatic trans. Hope to find out

J.R.
SoCal

The theory behind the 300hp 300 possibly beating a 300hp 351W would be that the 4" stroke of the 300 would make more low speed torque than the shorter 3.5" stroke of the 351W. Even if the two engines were relatively close in performance, it's still a technical loss for the 351, because it has the advantage of greater displacement and greater fuel consumption. A 300 hp 300 inline would no longer be limited to low rpm performance, but I believe because of the massive stroke, it would retain much of its charactistically flat torque curve throughout.

Displacement and volumetric efficiency = peak torque.
Stroke length influences the "flatness" or "peakiness" of that torque band.

Would the higher peak torque of the 300hp 351W with its 3.5" stroke be enough to overcome the flatter torque curve of the 300 hp 300 inline with its 4" stroke?? I wouldnt make any bets, I just wouldnt be surprised if the 300 pulled it off.
Against a 302 of equal hp, since the displacement is also equal, I would bet on the 300, but the larger 351.. not sure.

p.s. I'm not a big fan of 351W. I'd take a stroked 302 anyday.

[J.R.]

Against a 302 of equal hp, since the displacement is also equal, I would bet on the 300, but the larger 351.. not sure.

p.s. I'm not a big fan of 351W. I'd take a stroked 302 anyday.

Well, my '69 Fairlane with 351W(back to stock engine specs now, except only 9.5:1 C.R.) has a fraternal twin living in its 'fleet', a '69 Torino wagon with a stock 302! You're right if you'd guess that the 351 can beat up on little brother, but it does so in spite of weighing more & getting better fuel mileage! Trans & axle gears have identical ratios, so I can't explain the mileage thing unless it's due to having only a 2bbl on the 302. A long-time Ford parts manager acquaintance once told me that, from his view of parts/service flow at the dealership level, the 351W was the most reliable and trouble-free V8 in Ford history. Guess it all depends on one's specific set of experience(s).

When my truck destined to be powered by 300" BB6 joins the 'fleet', it will have a lot more torque than the 351W, but it will also be the only one of the bunch(for awhile) with EFI, a turbo/intercooler, and 4.88 gears. So I guess there will have to be some dyno pulls to know how much more power/torque that 300 has vs. the stock Windsors. Still it will be interesting, since each of the vehicles mentioned weighs between 3400 & 4000lbs.


J.R.
SoCal

[tj300]

What everybody else has been saying... Hotrodding is hotrodding, whether it be a bent 8 or a straight 6.

More airflow equals more power, just at higher RPM's

..........

Don't forget spark,( ignition).