Camshafts: What effect does increased lift have on performance?

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Newbomb Turk said:
I was doing some testing on a 340 last week. It has a very small cam in it. Too small but it was picked for “drivability”.

Anyway, when it was last in the car we installed 1.6 rockers. With a geometry correction kit.

The cam was supposed to lash at .028/.032. I never lash anything that loose. But when the rockers went on, I did the math and it came back some big number.

So set them, against my better judgment at .028/.032 and went to the track and it was Sloooooooooooooow. I didn’t want I work on it at the track so we finished the day and left it alone.

On the dyno it was a P-I-G PIG.

I decided since it was on the dyno I’d tighten them up.

I could tell when it lit off it was much happier. Idled better, took load better. It was just better.

First pull was up 40 hp.

In this case the cam is so small that it will respond to anything that makes the cam bigger.

I killed any power gain by opening up the lash more than it should have been, regardless of what the math says.

So between the lash decrease in the lash and the 1.6 rockers it showed a nice gain.

Obvious had the cam been correct, or at least been closer the gain wouldn’t have been as big. If any.
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Can you post the before and after lash change Dyno sheets?
Thanks
 
BSB67 said:
Is this the cam that’s “over” at 5,400 RPM in a 360?
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That cam 248/256 .558/.550 is in my Daytona 2900# without my fat *** in the seat! 10.5:1 and EQ 1.92 heads and victor intake. It will spin to 6K with 32/14.50's and 4.57 gear. Its a little wined at my elevation 4200da at times 6K, but by far the best grind so far. The 242/242/.510 Schneider solid I run in the 360 Dart 3.91:1 26" tire 4spd with 1.94/1.60 308 heads is winded at 5400. the 242/510 is a great all around grind, and both are on 110 Lsa for a little better vacuum at this altitude. Again I loose about 500 rpm struggling with low Da. Both cams are SFT.
 
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Illahe said:
That cam 248/256 .558/.550 is in my Daytona 2900# without my fat *** in the seat! 10.5:1 and EQ 1.92 heads and victor intake. It will spin to 6K with 32/14.50's and 4.57 gear. Its a little wined at my elevation 4200da at times 6K, but by far the best grind so far. The 242/242/.510 Schneider solid I run in the 360 Dart 3.91:1 26" tire 4spd with 1.94/1.60 308 heads is winded at 5400. the 242/510 is a great all around grind, and both are on 110 Lsa for a little better vacuum at this altitude. Again I loose about 500 rpm struggling with low Da. Both cams are SFT.
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Are the heads ported? RPM ceiling you list appears a little low.
Not accusing just wondering.
 
rumblefish360 said:
Are the heads ported? RPM ceiling you list appears a little low.
Not accusing just wondering.
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Neither set of heads had been modified. When I was racing at 1400' I ran a 238/238/.558 solid with speed-master 2.02 heads and 9.5:1 in the dart and it was done at 5800. 101.3 on street tire in the 1/4. Low Da racing is a challenge... Hard to put enough compression in the engine on a budget. Schneider has been a big help.
 
Illahe said:
Neither set of head has been modified. When I was racing at 1400' I ran a 238/238/.558 solid with speed-master 2.02 heads and 9.5:1 in the dart and it was done at 5800. 101.3 on street tire in the 1/4. Low Da racing is a challenge... Hard to put enough compression in the engine on a budget. Schneider has been a big help.
Click to expand...
Ahhhhhh, very cool, quite nice. Thanks!
 
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