1.6 rockers & clearance

[Streetbu]

Question for you guys. Do you really need to buy a Louis tool to drill out the push rod holes in SBC cylinder heads for enough clearance to run 1.6 ratio rockers? Or can you just use a file or a drill bit? I know way back when Comp Cams came out with roller tip rockers my dad & I installed a set on his Grand Prix and had no issues. Obviously his cam was stock. Mine is not 😉

 

[bracketchev1221]

You pretty much nailed it. You have to check for clearance. You may need to cut it if the cam is large enough. It cleared with the stock cam because the pushrod side of the rocker had minimal travel. The Louis tool is good to have, because it keeps the hole in a straight line. I can tell you you'll be there for quite a while trying to do 16 holes by hand.

 

[Streetbu]

Hmm. Ok thanks for the tip!

 

[383_GrandPrix]

What heads are you running? I only had to clearence a couple of pushrod holes in my Edelbrock heads because they didn't line up with the lifters properly, not because of the 1.6 rocker rasio. I also had access to a mill, so that made it easier.

 

[SRD art]

In my 406 SBC I had Summit brand 1.6 roller tip rockers on a Comp 268 cam with factory 400 heads and push rods with no issues or need for clearancing. That put the lift right around .510. Good luck!

 

[Streetbu]

Vortec heads. Cam is small. 465 lift with 1.5's but goes to 496 with 1.6... that's why I was unsure if I'd need to

 

[Streetbu]

I have a set of full roller 1.6 rockers. I'd love to use them but then also thought about the valve covers and them not fitting. Not sure what I'm going to do now.

 

[64nailhead]

Question for you guys. Do you really need to buy a Louis tool to drill out the push rod holes in SBC cylinder heads for enough clearance to run 1.6 ratio rockers? Or can you just use a file or a drill bit? I know way back when Comp Cams came out with roller tip rockers my dad & I installed a set on his Grand Prix and had no issues. Obviously his cam was stock. Mine is not 😉

Never heard of such a thing. The difference between a 1.5 and 1.6 rocker is miniscule. If you have slotted holes in the head for the pushrods, then you will be fine. Of course it's worth checking. You mentioned your using Vortec heads and if my memory serves correctly, then all stock Vortec heads used self aligning rockers and the push rod hole was round. Again though, swapping to a 1.6 self aligning rocker will not create an interference issue with the pushrod and head.

Now, if you are replacing factory stamped steel rockers with a roller rocker, then you can be assured that the rocker will interfere with stock valve covers.

I was a little foggy reaing your post of exactly where the interference issue is, can you explain some more?

 

[Streetbu]

Never heard of such a thing. The difference between a 1.5 and 1.6 rocker is miniscule. If you have slotted holes in the head for the pushrods, then you will be fine. Of course it's worth checking. You mentioned your using Vortec heads and if my memory serves correctly, then all stock Vortec heads used self aligning rockers and the push rod hole was round. Again though, swapping to a 1.6 self aligning rocker will not create an interference issue with the pushrod and head.

Now, if you are replacing factory stamped steel rockers with a roller rocker, then you can be assured that the rocker will interfere with stock valve covers.

I was a little foggy reaing your post of exactly where the interference issue is, can you explain some more?

Supposedly the holes cast into the head where the pushrods pass thru are small and when you increase lift above what they were designed for stock, you can run into issues with the pushrods contacting the side of the hole.... Google Louis tool

Besides that, I was hoping to use stock valve covers and full roller rockers. I think that is a pipe dream though Hahaha

 

[383_GrandPrix]

If you are planning on using vortec heads, it's worth reading this article;
http://www.superchevy.com/how-to/97458/