neat ideas on head porting

[timcosby]

stumbled upon this nad i think may be of interest to some here. five or six parts to it. http://mototuneusa.com/power_news_--_think_fast.ht
may or may not relate to our 14 hp monsters but it might.

[Its_not_a_honda]

Originally Posted by timcosby

stumbled upon this nad i think may be of interest to some here. five or six parts to it. http://mototuneusa.com/power_news_--_think_fast.ht
may or may not relate to our 14 hp monsters but it might.

Link does not work

[Mallen]

First go to the base url: http://mototuneusa.com/
Then scroll down to the bottom of the page, and on the lower left corner look for: Power News Preview
No idea why it forces you to do it manually.

[timcosby]

this was copy and paste from part 2 http://mototuneusa.com/power_news_--_homework.htm
maybe its the dashes messing it up

[timcosby]

this is the page for all links http://mototuneusa.com/thanx.htm

[Azhule]

Basically "Clay and shape for a Smaller/Velocity Stacked Intake Ports to gain 7% more power"



There is someone with a KLR650 that claims their "Big Bore/fully built engine" is making close to 90 horsepower (at the wheel) with the help of "Small/Velocity Stack Intake Porting"... the power/numbers I feel are a bit suspect due to the Dyno they are using... seen too many "extremely happy customers" when they get numbers back on their (stock) bikes/cars...

[paulsstag]

Originally Posted by timcosby

this is the page for all links http://mototuneusa.com/thanx.htm

i'm going to say that its possible in the right circumstances. Its possible the ports have been made bigger and bigger over the years to increase the power of the engines ? Anybody here on the site remember the Ford Cleveland V8?

Basically the ports( 4 venturi heads)(4V ) were hugh by factory standards and a lot of horsepower could be had at very high rpms . The 2 venturi heads (2V)were too restrictive by the same measures. Because the 351C engines were used in mustangs ( and others ) the factory did not want them revving to 7000 plus rpm where the ports started to work well. You could a few years ago buy a port plate that pretty much covered up about a third of the port ( looked similar to the jb welded port). Much better torque and horsepower was the result.

The Australians Built a new cyl head (called a 3V )that took the best properties of the 2 heads .

Some one needs to try it on the 229 and let us know.

[ben2go]

Originally Posted by paulsstag

i'm going to say that its possible in the right circumstances. Its possible the ports have been made bigger and bigger over the years to increase the power of the engines ? Anybody here on the site remember the Ford Cleveland V8?

Basically the ports( 4 venturi heads)(4V ) were hugh by factory standards and a lot of horsepower could be had at very high rpms . The 2 venturi heads (2V)were too restrictive by the same measures. Because the 351C engines were used in mustangs ( and others ) the factory did not want them revving to 7000 plus rpm where the ports started to work well. You could a few years ago buy a port plate that pretty much covered up about a third of the port ( looked similar to the jb welded port). Much better torque and horsepower was the result.

The Australians Built a new cyl head (called a 3V )that took the best properties of the 2 heads .

Some one needs to try it on the 229 and let us know.

I had a big block 351 Cleveland in a 73 Ford long bed Ranger custom cab. It was backed by a C6 auto transmission and a 9-inch positive traction rear axle.

[paulsstag]

Originally Posted by ben2go

I had a big block 351 Cleveland in a 73 Ford long bed Ranger custom cab. It was backed by a C6 auto transmission and a 9-inch positive traction rear axle.

I have never owned a 351 cleveland but a couple of 351 small block windsors but everyone i know that has had them seemed to love them.

Did your truck have a 4 barrel carb or a 2 barrel ?

[roundhouse]

Originally Posted by ben2go

I had a big block 351 Cleveland in a 73 Ford long bed Ranger custom cab. It was backed by a C6 auto transmission and a 9-inch positive traction rear axle.

I had a 1970 stang fastback with the 351 C with the 2v heads and a C6. Our cams were the same, comp 268s and we both had torquer intakes. My buddy had the 4V head and my car was way faster. I think he did not have enough cam and carb to spin it high enough to fully use them. I bet he put down more on a dyno but I am sure I put down more everywhere but the tippy top.

Cleveland was a great motor.

[Megadan]

Taking the already well designed ports that the manufacturer spent thousands of hours designing, modeling, simulating, and testing to get the right balance of intake velocity, flow, and swirl, hogging them out way too big, and then adding a sharp turn on the short side radius right before the valve is about as bad of an idea as I have ever seen.

I get what they are trying to do, but they have nothing to back up their claim with. 7% more power? That's vague. 7% more power where? A before and after dyno plot of multiple runs would be far more convincing.

They likely picked up a little more power in the lower RPM range due to that higher velocity, but I would almost bet there is a loss in high RPM power due to a decrease in total mass flow. Decreasing the cross section right at the radius, right before the intake valve seat will do exactly that, decrease mass flow (and likely increase turbulence).

In fact, if you want to watch a good counter video to this whole idea, I welcome you to watch one of my favorite channels who does a great response to this whole methodology.

[ben2go]

Originally Posted by paulsstag

I have never owned a 351 cleveland but a couple of 351 small block windsors but everyone i know that has had them seemed to love them.

Did your truck have a 4 barrel carb or a 2 barrel ?

It was a 4 barrel and the only owner before me upgraded to a Holley 850cfm. It ran really good and had a lot of low end torque. Low redline of 5000 rpm, IIRC. So far as I know, the truck was all original. The owner bought it new. I grew up working on cars with him. He was my mentor of sorts.



He bought the truck back from me a year and a half after I bought it from him. The bed had some rust issues. He had another short bed parts truck that had been hit in the front and had frame damage. He used the short bed from that truck, cut down the chassis on the good truck, and made it into a short bed. It looked really good when he was done. Couldn't tell the truck had ever been shortened.