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Discussion Starter · #1 ·
Recently I tried to run through the gears the way I expect to at the strip. I planned to shift at about 6400 RPM, but it started to "misfire" at about 6000 RPM.

Should my combo rev that high or am I expecting too much?

The AFR165 heads are new, and the valve springs have the right specs for my cam. The cam is a hydraulic flat tappet (230 @ 0.050, 0.512 lift) and I'm using Rhoads lifters adjusted to zero-lash plus 1/4 turn. I've checked the fuel system: there are no restrictions, the floats are properly adjusted, and it's got a new Carter high volume mechanical fuel pump. The ignition is running quite well (Accel Billetproof distributor supplying magnetic trigger to a Crane HI-6), and the timing seems to be dead on when checked with a timing light (16 degress initial and 36 degrees total). I think the jetting might be slightly lean (as compared to what is needed for maximum power), but I don't think it is really lean (I'm running an Edelbrock 600 with stock jetting at 5000' elevation).

Any thoughts?
 

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Sounds very similar to what happened to me last year when I went down in jet sizes, I thought I was to big but turned out I was way to small, I went from a 70 to a 68 in the primary, when I finally figured out what the problem was I ended up with a 73 in the primary and all was better, I know run a 76 in the primary with the new heads and I think it is calling for more.
 

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Discussion Starter · #4 ·
Last night I raised the rev-limter to 7000 RPM instead of the 6500, and it now easily revs to 6400. Just a few weeks ago I set it to 2500 and verified that it limited exactly where it should, but it seems that it's somehow kicking in early at the upper RPMs. I'll need to do more testing to see how far off it is, but it bothers me that I might not be able to count on where it really limits.

Has anyone else seen something like this?
 
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