I recently acquired my 69 Chevelle (had one in High School 25 years ago and now trying to recapture the youth...).

Anyway the car has a 350 bored 30 over with a set of fresh 461 heads, edelbrock 1407 carb on edelbrock performer intake, and a blueprint 350hp cam. I just rebuilt the carb trying to fix a backfire problem, found black gunk in carb from the previous owner not using fuel line. After rebuild and replumbing with actual fuel line I progressed on. Car still has a backfire out drivers side exhaust, sounds like a tight valve.

Pulled the plugs noticed that #5 and #7 were wet with fuel. Ran compression test all cylinders have 160-170 psi. On to valve adjustment. When I pulled valve pans I see roller rockers. I have adjusted valves on many engines with no problems, but they were all stock rockers. When I checked all pushrods prior to adjustment I was able to turn. I then proceed to begin proceed to turn #1 until exhust starting to open to adjust intake. I tighten roller rocker until feel tension when rlling pushrod, then 1/4 turn. Problem is when I do this I can no longer twist the pushrod at all. Is this normal with roller rockers. When I have done this in the past with stock rockers I still have some twist in the pushrod.

PS: I want to say what a great site this is.

You may be tightening it too far. Here's why:

You should tighten the rockers 1/4 turn past the point that they make CONTACT with the pushrod. If you wait until you feel resistance by spinning/rolling the pushrod, you may already be 1/4, 1/2 or who knows how many turns past the point of contact. Different for every engine build and every rocker.

P.S. There is a great way to set this correctly, just not as simply as you are doing. Do a search on the subject looking for racer1320's username, I'm sure you will find it. If anyone else has the link to that method, please pipe in.

It's very messy, but the absolute surest way to adjust hydraulic lifters is to do it with the engine running.

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Mike Newby

69 Chevelle 355/TH200-4R
97 Grand Prix GTP
64 Chevy C10 Pickup
79 Suzuki GS550

Here's an "anti-messy" way of adjusting valves with it running. Take a stock boneyard valve cover and cut the center section of the top out. Leave all the sides, the curve to top. Only cut the area to access the rocker nuts out.

Install this on the head with a rubber VC gasket, fire it up, and do the adjustment. No oil splashing around! Works better than deflector clips, "rocker stoppers", or anything else I've tried.

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"Atomic Batteries to Power...Turbines to Speed"

(The Minnesota John D)

'64 El Camino
383 - TH-350 - 12bolt - 4wh pwr discs
Bedded down for the Winter.