jasman19

Here is the problem, I put some new fast burn 383 heads on my stock 350 block. I also put some 1.6 roller rockers on as well. Well someone told me that I need a different length pushrod. I was disagreeing with him because I didn't change my cam. All I need to know is if you change your heads from stock to another type of head do you need to change your pushrod length? Also I have these roller rockers that I bought from summit and they are non-self adjusting. I was wondering if you just do the typical valve lash adjustment and how do you set the rockers before you start the car and listen for the ticking?
thanks for any help

305sbc

iTrader: (3)

Only if you want to get the rocker geometry right. I always check everything and then get the right length pushrods.
The engine will run with the wrong length, but it will cause problems in the long run.

jasman19

How do you get the rocker arm geometery correct? Is there a tool or a pic that I can off of? Sorry if I sound like a jacka$$ with this but this new stuff to me. Thanks for the quick reply

350camaro

There is an article in this month's car craft on checking push rod length.

Damon

Mr. gasket and Moroso make pushrod length checkers for not a lot of bucks. They come with detailed instructions.

If you're using hefty aluminum roller rockers you may find you have to get slightly longer pushrods than optimum on some heads becuase the bottom of the rocker arm can hit the flare at the bottom of the rocker stud- and you definitely don't want that.

jasman19

Alright I will see if my lam a$$ army shoppette has car craft, but thanks for the tip. Hopefully they do because that is the only place that I know of that has american magazines in Germany. Thanks again

Ricktpi

Just grind the bottom of the rocker for clearance. Don't sacrifice the correct geometry for clearance.

Basically you want the roller to start on the inside of the valve stem & roll to the outside with going off the edge.

305sbc

iTrader: (3)

You might want to save and magnify these.

jasman19

Thanks for those pics they should help out. I went out and looked at my rockers and lower ears and hitting that flange on my heads so I am going to call them good. Just need to check the geometry with these pics. Let you know how it goes.

94-6spd

Sometimes if you change your heads you WILL need a different size pushrod. Some heads have a different lenth valve stem. Also, if you are using retro-fit roller lifters you'll need a different lenth. You can get a tool from Jegs for about $13.00. This tool is what I use. Cheap and effective. You just put it on the rocker stud and use a feeler gauge to check if you need shorter or longer pushrods. The instructions are on the back of the package.

http://www.jegs.com/cgi-bin/ncommerc...18&prmenbr=361

Your other question about setting valve lash is simple. The way I do mine is turn the engine over until the exhaust valve starts to open just barely. Then on that same cylinder adjust the intake rocker. Next, turn the engine over until the intake valve of that cylinder opens all the way up and just almost closes. Just before it closes adjust the exhaust rocker.

When adjusting the rockers tighten them until there is no up and down movement or "lash" on the pushrod then a 1/2 turn.

Go through all of them the same way and it should work out fine.