340 dyno chart thoughts

frosty_the_punk said

On a stock stroke 340? that vacuum figure for that much duration seems unusually high to me. two possibilities come to mind. super wide lobe separation like you'd see on a blower or nitrous camshaft.

OR a solid lifter where about 10-12 degrees of the lobe duration is taken up by valve lash.

regardless, the point remains... everything else being equal. more duration and a tighter lobe separation will increase overlap and reduce idle vacuum. Your personal anecdotes are interesting, but there's just no disputing this fact as it's probably the most basic rule there is about camshaft theory.

Click to expand...

I've posted my cam specs several times. It's 255 at .050 on a 105 LSA installed at 105 with a STOCK STROKE 340. It will idle well at 800 but it's at 900 now, but I'd rather it be at 1100.

So, your are wrong when you say it cant be done. It's a very fast lobe for sure. None the less, it is what it is. Also lash is .014-.016 hot, so running its damn near zero lash.


Just because it is repeated over and over and over don't make it right. Too many guys are pissing away power because they won't learn camshaft and cylinder heads. In fact, if you looked at my flow sheets, you say my engine would be lucky to make 350 HP.

You can't stay in the 1980's forever.