Something strange going on around 5100rpm.

I'd say check your plugs, plug wires, coil, and opti.

More than likely you burnt a plug wire.

 

plugs wires were probably arcing off the headers.

change wires try again.

while your at it check your spark plugs too.

I had a spark plug loose and half a hesder gasket on my car and I dynoed 278/317

this was before my cam.

 

I went from 255 hp and 280 tq down to 244 hp and 259 tq w/ the addition of my shift kit and 2800 stall....if that helps any in this post.

 

Arching wires will kill hp.....put some new wires on and route them away from the headers anyway you can....I used a variety of tie straps and the wire loom holders on the side of the block to steer clear of the headers....oh and when you order wires order either the taylor 8mm because i couldn't get the MSD wires to work with stock wire looms but i've heard of people that said they had no prob.....you won't tell a difference in the wires anyways....

Michael

 

I dropped 50rwhp from an arcing wire on the dyno.

 

At my last dyno run the operator said that there was
lots of noise coming off my plug wires (assuming it was
electrical noise) and that I should replace them. These
wires only have about 25,000 miles on them but they
are probably 5 years old (TPIS wires). I would say it's
worth while to replace the wires. I'm going too.

 

Dude my dyno looks just like yours (rough trend @ abt 5k) and Larry told me it was from vibration (still have 273 gear) the car topped out @ 170 or so. I did everything before the dyno run plugs, wires, opti and don't seem to electrical. When I drive my car @ wot I don't feel anything like that trend shows (its smooth).. Maybe its something with their Dyno if I new how to put mine up I would show you but its choppy as hell 15 to 20 HP losses and spikes......................

 

My Car Dynoed 264/297 Witht he mods listed int he sig, and that with timing being pulled, so I'm sure your number are supposed to be much higher. Here is a link to the dyno sheet. The first pull had a miss where you see the dip, the 2nd is the better numbers.
http://community.webshots.com/s/imag...6Kvpkjs_ph.jpg Copy and paste if needed.