Ported 390xp vs. Ported MS460

[mdavlee]

Hooray Mr. Fluffy??

576xpAT was a bad dude.

That do run good if you don't mind the fluffy.

 

[Hedgerow]

I know where Mr. Fluffy lives now....
In Wisconsin.

 

[mdavlee]

I know where Mr. Fluffy lives now....
In Wisconsin.
View attachment 21079

I don't know where the last one I had ended up.

 

[awol]

They're not quite so fluffy with the optional hard mounts installed.

 

[mdavlee]

They're not quite so fluffy with the optional hard mounts installed.

Fluffy for the 390 size in a 70cc package. They will run when ported though. Surprised me when one was faster than a 372xpw.

 

[Hedgerow]

I shall own Mr. Fluffy some day..

 

[wshamby01]

A ported 576 is a serious saw! It will leave most 372's in the dust.

 

[Hedgerow]

They're not quite so fluffy with the optional hard mounts installed.

It's not the mounts as much as the overall poofy
Appearance and size.

 

[riverrat2]

Not bad at all then. They can really run with a little extra compression and raising the transfers.

exactly!!!!

 

[Terry Syd]

I'll have to measure and see. I usually free hand file my chains and don't measure.
Side raker removal can be as important as raker height. This particular chain has the numbers filed off the sides and the raker height is close to factory from what I remember seeing when I laid a flat edge to see where they were when I was done.
I also cleaned the gullets and they took an edge too...whether it actually makes contact with wood to help is something for NASA scientists to figure out. Lol

"Side raker removal" - what is that? It sounds like you are thinning the raker.

 

[Chainsaw Jim]

"Side raker removal" - what is that? It sounds like you are thinning the raker.

The outside of the raker is angled and narrows off the gap for the side of the cutters. I have it worded wrong. Not removal but filed enough to be vertical. They end up a wee bit thinner, but not sharp. It's usually not necessary until the teeth are worn way down.

 

[jake wells]

When emissions started playing into how engines were designed they went towards more stroke and shorter rods. The 454 had a horrible rod-stroke ratio compared to a 396 & 427. A SB 400 is even worse! This all started in the mid 70's


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i like my 300 I6 4 inch bore with a 3.98 inch stroke. and torque in the right places never did like any other engines except the 302.

 

[MustangMike]

For whatever reason, 4" bore engines generally did very well, including your 6, the Ford 289, 302 & 351 and GM 302, 327 &350.

 

[mdavlee]

5.9 Cummins is 4" bore. Little more stroke though

 

[jmssaws]

Some combos work much better than other's, a 064 will be strong with a 54mm cylinder on it but it's hard to beat the 52mm cylinder.

 

[Chainsaw Jim]

I just finished pulling the 390 apart because it quit running right. I suspected bad seals but it turns out two cylinder bolts on one side were loose. Whoever ported it left a mess of silicone type gasket maker beaded up inside the crank and it was just starting to cook. Here's a piece that was dangling in the case...

Then I took a few pics of the port work.


The intake isn't really chamfered to my standard so I have no choice but to get the grinder out....and I'm not stopping there.

 

[jmssaws]

That doesn't look very good to be polite.

 

[Mattyo]

hmm.... err.... looks like ... i did it .... lol..... but it wasn't me. how come that intake is polished, but the exhaust is all gummed... and the roughness of those lowers, jeepers...

 

[Moparmyway]

That doesn't look very good to be polite.

It looks like crappola

how come that intake is polished, but the exhaust is all gummed... and the roughness of those lowers, jeepers...

Look at the divots in the one side of the exhaust port, looks like the lip is still there too

 

[Lone Wolf]

Surprisingly close.....except in looks....the 460 is soooo much sexier....
Usually a 13cc head start is a tall order to overcome. (Always wondered why the two are even compared to one another)

Because it was so close and overcame the CC deficiency!