There's something not right about that. The stock torque peak is at about 2100 rpm. If you add 20 degrees of duration at the seats and probably 50-60 degrees at 0.050 it isn't going to peak at 2100 unless there is something very wrong.

 

Yes, I would have to say I can't agree with 450 lb. ft at 2000 out of an EFI 300 cubic inch motor. That's even less likely than 450 lb. ft at 3300, which I also think is unlikely out of a NA motor. I just can't see the torque numbers that high-they're not supported by the displacement and breathing ability of the motor.

Look up the specs for the biggest gassers-they produce 450-480 lb ft. Dodge's cast iron V10 and Chevy's 8.1 liter. 488 and 496 cubic inches, respectively. But not at 2000 rpm. Even these big blocks are not set up to make their torque that low-maybe characteristic of V's, sure, as you want them to rev a bit to make some horsepower-but what chance does a motor that has 188-196 cubic inches LESS displacement and inferior breathing have in making equivalent torque at much lower rpm?

I think the answer is "none at all."

A bigblock V8 generates 450+ lb. ft. with displacement and (usually) higher rpm's. A diesel does it with displacement, compression and a turbo.

And a NA 300 would do it with what? There's nothing there to give it the ability to do so at low rpm's. No big block displacement. No diesel 20:1 compression. No turbo.

Call me a skeptic of Clifford's ability to perform miracles.

 

I agree, seems the 270 has 2 more advertised degrees and 22 more at .050 over the stock, wouldn't make sense for it to peak lower, he was running 4.56 gearing but that wouldn't cause that.

FWIW, he also only reported a peak hp of 220, I haven't done the math but that seems on par with the TQ, I agree though, the TQ peaked suprisingly low.


309Ford

Inferior breathing ? There is alotta room for port growth, the only drawback is finding someone that knows what needs to be done to said port.

 

Yeah, but port it to increase flow and your torque peak rpm increases. So peak torque is no longer at 2000 rpm, which is the torque peak of the unmodified motor. It moves higher in the rpm range. To make big block torque, you've gotta have high flow that's high in the rpm range to move enough air to generate said torque. Which kills low rpm torque. I've seen smallblock V8's that generated big block torque, but they always had to generate high rpm to do it. When they were done with them, the motors were almost unstreetable because they had zero bottom end and little midrange power. The torque peak rpm was way up there, in other words. Why would the 300 be any different? As far as porting goes, they've still gotta breathe through the valves, and we have only six with smallblock V8 displacement. You can buy smallblock V8 heads that will flow better than anything you can do with a 300 head, short of having a custom one made from scratch.

I have my doubts that the 300 will make big block torque at low rpm. The physics just ain't there. Hypothesis is all well and fine, but the math's gotta add up for it to work.

 

I keep saying the target rpm of 2000-3300 means little to me but I will explore the idea that the torque should exceed stock if the heads are ported.



Your right to a point, if we are talking a simple clean up of the port, bowl areas, then there is a likelihood the TQ would increase with no significant peak RPM increase on an otherwise stock engine, with that said, your not gonna gain 150 ftlbstq, we agree.


Now the idea that a built engines peak rpm TQ would increase, simply due to port work on the head isn't accurate. The new cam shaft can increase cylinder pressure, which will increase low end and bring that peak down, other factors like increased compression change the way the game is played as well.


There is no voodoo here, Col Flashman made 400 at 3200 rpm, now do you think the TQ went from zero to 400 at 3200, not likely given the inlines ability to produce a flat torque curve and the realization that the camshaft used was a mild one. I would still bet, at 2000 rpm the modified engine would produce alot more TQ than stock. Also take into consideration the camshaft used, in Col Flashmans case, it was a mellings camshaft, unless someone can prove otherwise, a camshaft made by one of the larger companies should have a more updated profile and produce a significant amount more when it comes to power. Slap a well tuned efi onto the bad boy and we would have something.




Then we are looking at different small block v-8's, sure if the hp peaks high, then the TQ will peak high but its also possible to bring the peak TQ down with a more TQ oriented camshaft/ goal and bye bye hp.

 

I'll post more later, but with port work, the rpm at which peak torque occurs must move higher in the rev range because you now must move more air to get the potential out of the motor. You're not taking advantage of the breathing benefit if you continue to use a cam that produces torque lower in the rpm's. Therefore, you're not getting the most the motor is capable of doing.

Again, the other stumbling block is displacement. The 300 cubic inch motor is not moving nearly as much air as the big block per revolution of the crankshaft. Air makes power and torque, and the small motor can only move so much air because of limited displacement and rpm's. Port it all you want, but you've got less air moving than the bigger displacement engine when both are turning low rpm's.

If big block torque was possible at low rpm's in small displacement motors, then the large displacement motor would not exist, and we'd get everything done with big port, high flowing smallblocks. The fact that we don't have this situation should tell you something. The reality is that small motors that are set up to breathe and actually do make high (big block 450 lb ft.) torque have poor low speed torque, or are at least nowhere near their torque peak at low rpm. You've got to address the displacement issue in your argument to convince me.

Take a look at the stock rpm torque peak of the motor. 2000 rpm. Now you've ported it, and somehow you're gonna make much more torque-450 lb.ft. versus 265-at the SAME rpm? A 70 percent increase in torque without changing the torque peak? Not possible. You're moving the same piston volume of air at 2000 rpm, and the velocity of the air (and vacuum) have dropped. The torque peak must now move higher, because you're not getting nearly the potential out of the motor unless you put in a cam that lets the motor breathe. Only then are the potential increases in torque realized. Then, with revs and lots more air (to make up the displacement deficit), you can make a 70 percent increase. A 70 percent increase at the same low rpm is not possible.

Show me a 450 lb. ft. NA 300 that produces this torque at 2000-3000 rpm and I'll concede it can be done. All I've heard is theory so far. Dyno sheet please.

 

Dude we are getting nowhere, your not paying attention to what I am saying, your more interested in proving a point, of which I am not debating. I am not supporting cliffords claims, what I am doing, is putting two and two together from third party sources and making a judgement based on that, as to the possibilities of the 300.

AGAIN, I am NOT interested at what RPM the 300 makes 450 TQ, just at the possibilites that it CAN make 450 TQ. If you have a 300 making 400 TQ at 3000 rpm, there is a high likelihood, given the flat TQ curve the 300 generates, that it will exceed the stock engines TQ output by far, where the stock engine peaks, after all we are only talking a 1000 rpm margin here. Again, if your interested in lowering the peak TQ, so it comes somewhere closer to where the stock TQ peaks, then another camshaft besides the mellings would be inorder.

Your right, other than the fact a 300 can make 400TQ with a MILD camshaft on a carbed engine, PROVEN, the 450TQ is speculation, but you figure it out, a better cam and efi will up the TQ, no doubt about it, as to whether it fits your applications needs, thats another ball game altogether.

 

A motor that would make 450 lb. ft. at 5000 rpm wouldn't be of much use as a truck motor if it were a 300. A 300 that could produce that much at 3300 rpm would have considerable utility, if it were possible. Count me as one who is very interested in what rpm the 300 makes its torque, which determines its potential as a truck engine. There's no free lunch, and my point was that it is difficult to have very high low speed torque in a 300 cubic inch engine.

Trouble is, nobody has produced anything which could be considered as clearing up the issue and revealing if high low rpm torque is possible in a NA 300. Guys have supposedly dyno'd their motors, yet I've never seen a graph or figures on the output of the motor at various rpm, and most especially at low rpm. Torque output well below 3000 is of most use in a truck and that's what I'd like to see. As I stated before, I'd like to be able to assess the overall utility of the motor.

Yes, the theory says that if the motor has a certain torque at a certain rpm, it will have a given amount off idle, but we're making changes (porting, etc) that may affect the actual output at low speed. The torque curve may not be as flat as you are assuming if changes have been made. The 600 cfm carb and porting of Col. Flashman's motor would imply a higher torque peak than stock, as his numbers confirm. Did it hurt low rpm torque, or is it still higher than a stock motor's torque at low rpm's, even with the modifications? Without a dyno chart we'll never know. This could be the best way to build up a 300 for truck use, but we don't have enough information.

I think it's reasonable to ask to see dyno results rather than extrapolating what I THINK might be happening. I think the real answer is to dyno my own sixes and find out for myself rather than rely on third hand information about what somewhat else said the motor was capable of without supplying any other information than a single figure for max torque and max horsepower.

We won't resolve the issue here until someone does this. Might as well be me.

 

Finally a meeting of the minds, if the TQ peaked at 5000rpm, your right, it would be a useless POS for a street truck.


Whats your setup now?

 

I have two Ford sixes. One is a bone stock "93 EFI six, Mazda tranny, 4.10 gears in a pretty little candy apple red Flareside. Burns zero oil, runs like a top.

The other is a .060" overbore 300 in a 1980 Ford (309 cubic inches), headers (dual outlet), Holley 390, Offenhauser C series intake manifold, and a bit of a compression bump obtained by milling the head with an assist from the overbore. Ports smoothed, polished and matched but NOT enlarged, as I wanted to keep the torque peak low. Straight up cam timing, milder cam like the Colonel's. This motor is a workhorse.

The C series and 390 Holley are a bit of a mismatch, as supposedly the DP is better for a milder cam torque motor used for hauling, but despite this the older modded motor has far more low speed torque (using the unreliable seat of the pants comparison). What makes this a more valid method of comparison is the fact that the newer EFI truck is both lighter (200 lbs) and has lower gearing. The EFI is 16:1 in first, while the older truck (T18 tranny) has a 6.32:1 granny and 3.09:1 normal "pavement" first gear with 3.55 diff, so it is only 11:1 in first. The modded truck pulls harder in "pavement" first than the EFI truck does, and will lug like mad down to 4-500 rpm. The EFI truck dies if it has much of a load below 1000 rpm clutch engagement. I understand some of this may be due Ford retarding the cam to meet emissions in the EFI truck.

Still, I'd like to know the true difference between the two at off idle and above, and what effect the manifold/headers/polishing/compression had on low speed torque. Like you, I think that improved breathing helps torque even at low rpm, but there may be a point where large ports hurt low rpm torque if overdone. I'd like to find out just what the differences are between the two. I just don't have the money to run down all the possibilities, unfortunately.

A local shop offers two dyno runs for 75 dollars, and I'd like to put each truck on their machine to quantify the difference between the two. It would be nice to build a motor that has maximum possible low speed torque, and helpful to know which modifications help and which hurt. Or, possibly, build one that has good low speed torque and decent midrange. I think I can make decent guesses, but the contribution of each modification would be nice to know. I got lucky and cobbled together a good running six without any forethought about what works and why. Now that I've had time to reflect on it a bit, I'd like some more answers.

 

Cool....

odd what you mentioned about the efi lugging down...

I've impressed some people, by moving objects/vehicles/what have you by simply easing off the clutch without giving it any gas aka using it like a tractor.

Sounds like if your interesting in further modification, the dyno time might be worth your effort, just don't tell us the results, that would be third party info...

messing with ya, good luck

 

silverstreak has some dyno runs of his truck with a few mods. showed a set of headers really helped flatten the torque curve.

 

I only saw the dyno run with the headers. Didn't get an opportunity to see the run without the headers. As I recall that's about all that was on the truck as far as modifications went.

 

Headers first, then stock 3.8 rockers (higher ratio than stock 4.9 rockers) if I recall correctly.


Well, I e-mailed clifford, the response was as follows:


We'll see if they send the 300 dyno sheet reflecting 450TQ.

 

i once witnessed a 300 in an 83 2 wheel drive do a small wheelie off of the line in granny and bust the tires loose in every gear with a t18, after his run i asked him what he had on his engine, he popped the hood and said the head is ported everything else is the intake and exhaust, weiand intake 750 cfm edelbrock carb and open hedman header, yes he had dot drag radials, 5.32 gears and locker but it still had to take some major power and torque to do that