For the moment, skip all the other replies. Let’s focus in on the Comp Cam and it’s lifters. The cam has an aggressive duration and the lifters are taxed at the rate of lift that what your probably hearing is a normal thing. The pushrods should be depressing the lifters to the Comp Cam spec. (which I read a few days ago and can’t remember damm it!) Failure to have the pushrod depress the lifter enough or to much will cause a loud valve train by itself.
The factory rockers are know to be less than there advertised 1.5 ratio. There fine for use on a low lift cam such as yours.
Your saying “Why? It’s a .500+ lift!“
Not exactly..... the lift given on the cam cars is the Theoretical lift given at a 1.5 rocker ratio which doesn’t account for the valve trains oddities of the lifter angle and pushrods angles and lastly, as mentioned, less than a 1.5 rocker ratio that is normally found on the stock stamped rockers.
Now, back to what everyone else was saying...
The best fix is a geometry correction that starts with a call to Mike @ B3 Racing & ask him for his recommend rocker that he likes. Since you probably do not have roller rockers, ask Mike what he likes. Now between the two, geometry corrections and new and true 1.5 ratio rockers, not only will you have a quieter valve train but a corrected one that will be worth the price of it all in gaining back the lost power you intended the engine to have.
It is also IMO that you move to a 1.6 rocker for two reasons. First, it will add a minor boost in intensity to the cam. Second, the more lift you have with the better Edelbrock heads the better since the best flowing part is when the valve gets lifted higher.
I just got done with a 340 that is (temporarily) using the OE rockers on the XE285HL cam w/as heads (same as yours) and it runs just fine. However! Down the road I will have just what I suggested. FOR SURE!
Make good use of the head and lift that freakin valve up high to take advantage of the heads air flowing abilities. Otherwise, you could have given your stock iron heads a good valve job and a bowl porting and ended up at the same place. Just with more money in your pocket.
BTDT... always afford the best head you can and then take advantage of all it has to offer!
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