ok i am not sure but i believe these are adjustible rockers because they use poly locks?? am i wrong?? pardone my ignorance. do u have to put each cylinder at tdc in order to set preload ? how do i set preload with adjustible rockers?

here is the part number and link to thunder racings page
part number 63-13753-KIT
http://www.thunderracing.com/catalog...vid=7&pcid=108

 

Yes, the magnums are adjustable. Easy way to do it is to go by fireing order when installing adjustable rockers. When the #1 piston is at tdc on the compression stroke, both the exhaust and intake lobes are on the base circle of the camshaft- just run the polylocks down untill all of the slack is taken out of the pushrod and then another half turn on stock lifters and lock em down. Continue on to each cylinder @ tdc on their compression stroke and repeat. On the comp r lifters you will not go a half turn- instead just measure the preload and set it were Comp Cams recommends. The way I do this is pull all of the spark plugs out and have a buddy bump the engine over with the starter while I have my finger in the plug hole and when your finger is forced out the stop right there- your on the compression stroke for that cylinder.

 

Also you will have to releive the drivers side valvecover to clear the rockers if you have centerbolt heads(99 and up).You do this by removing the splash sheild and grinding down it's mounting boss.Mine ran better with a bit more preload on the stock
lifters ,it seemed to like 1/14 to 1/12 turns.Hope this helps.

 

I took the set screws that go into the polylocks and ground the face of the set screw so it was PERFECTLY flat and flush. This only take a couple of seconds on the side of your grinder wheel. This helps the set screws buck up against the rocker studs when you tighten them down. When you put the set screws in use a wrench in one hand to keep the polylocks from turning and then tighten down on the set screws REAL tight. Use a "T" handle allen wrench. This will give you some added torque.

 

exactly what these guys said...but measure cold preload at .008-.010" using a dial indicator..or about 1/5 turn with comp r lifters. Soak them good in oil before install.

 

how does th dial indicator work? how does it fit over everything?

 

Good suggestion, I do that also on my engines.

 

put the dial indicator tip on the rocker tip and measure .008 deflection. Of course you have to mount it to the head/block