I think that the rockers you require will depend on the profile of the cam. Roller rockers are better but you only need them if your cam has an agressive profile. At least that is what I think I have read in my reading the last few days. Other guys will pitch in with more specific detail.
What head is in the top end package you have? What is the chamber size?
It is most likely you will require adjustable rocker gear as the heads will be using screw in studs. You need to know the size of the stud before you purchase the rockers. You do not need to purchase roller rockers though they are the best option if you can afford them. As I have side you need to consider the stud size (where 3/8th is standard), and the rocker ratio (where 1.6:1 is standard). You may require higher rocker covers when a full roller rocker is employed.
So your options are:
1) Best Option: Roller Rockers. Least friction and side loads.
Many brands and various construction materials and quality. The last 5 performance engines I have build I have used the Ultra Golds. Such as below
As far as the push rods are concerned you will need moly hardened pushrod that are suited to use with guide plates. Stock 289 is 6.825 You should measure them for the required length though the head manufacturer will gneerally provide the recommended length which will often be close enough and certainly fine for a mild build.
So I assume you have the E Street kit so you have these heads
As Boof said you can't guess the rods you need to work it out depending on what's in the engine.
scorpion endurance roller rockers are a little lower then most and will fit under most stock covers, similar price to the Comp cam gold's from memory
The other benefit to rollers is that you average more lift across the duration of the cam, it's only a little but it all helps. A standard rocker is like sled it slides across the valve and it fulcrum on the post. a roller has more of an up and down movement ie less motion is lost.
First of all, thanks to boofhead for all the great info!
Yes the heads are e-street and i believe they have a 60cc chamber.
I guess the way forward is to buy the full roller rockers (either the comp cam or edelbrocks) and fit them to the heads. The scorpion endurance rockers would be great shaun if they do fit under the new set of aluminium covers i've already got. Then I'll need an adjustable pushrod to measure before buying a new set of rods.
How do you know how long the pushrods need to be? Is it simply by bolting the rockers on and seeing where they contact the top of the valve stems?
I like to use checking springs to do the test. Others use a solid lifter. There are various videos and information around. Some help in the tech section here.
You are basically looking to mark the top of the valve stem with blue marker and then install the rocker to zero lash and rotate the engine and have a look at the mark left by the roller. The finer the line the better. It is also great to have it centred though that is less important than the fine line. Get it to close to a 1/16th Inch as possible and it will be close enough. Here is a video with further information that will provide an idea of what to look for. Note: Its a chev though same process.
You may also want to calculate the compression ratio as well, Think the Edelbrock heads are 60cc or larger chambers, if your engine don't have flat top pistons you may drop compression a little too much, you may want to take a cut of the heads.
You have studs so it is fully adjustable hence then you need to adjust the rockers following the appropriate procedure so you get the correct preload on the hydraulic lifters. Do not just bolt them down.
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