I just put Vortec heads and an XE268h cam in my camaro. Everything seems to run halfway decent, but when it put the car from park to reverse it makes some kind of knocking noise. After about 25 minutes of driving it does it in drive as well. When driving down the road it doesn't make the noise. It doesn't in park either. I'm hoping it's nothing big, but I'm kinda scared. Also, the valves are much noisier with the new cam compared to the old one. Any ideas? Thanks

could be a loose flex plate/flywheel

Check your u-joints.

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70 Camaro Sport Coupe 350cid balanced, blue printed and running smooth.
74 TA under construction 400cid bone stock.

When I did a cam change I slightly bent the inspection cover for the bellhousing and it made a strange knock. Worth a try.
also my valves sounded the same.

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Jim O.
Original Black 73 RS LT Z28 a/c tremec 5speed
tfs 23* heads xe268 13.62 @103.3
movie 1.2mb www.members.cox.net/jims73z/jims73zvsredss.mpg (http://www.members.cox.net/jims73z/jims73zvsredss.mpg)

[This message has been edited by jims73z (edited February 04, 2003).]

Loose bell housing bolts. Lock tight them and torque em.

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Mark
4spd Z28's owned '68,'71,'77new,'78new,'80new,70 still,daily driver 87 G/N.
Home Page on 1970 Z28
http://members.rogers.com/mlvd/

Chevy's Baddest Toys
http://members.rogers.com/ldd54/

Loose tourque converter bolts.

The 268 tends to be noisier than other cams cause of the very aggressive ramps. These cams are about as aggressive as you can get with a flat tappet.