xrated

Hey guys,

How do i change my stock rockers to 1.6 ratio ones. Do i just unbolt the old ones and bolt on the new ones? Im confused as I have heard of 'easy-fit' bolt on rockers that require no mods to the heads. Im not sure if these are for chevies, the chevies are all stud type bolt ons anyway.....arnt they?

Can someone please outline the method used to change the rockers. Thanks.

Do i have to change the pushrods? What size studs are factory..3/8 or 7/16?


[Modified by xrated, 6:57 AM 2/14/2002]

DavidOrr

I'm sure someone more knowledgeable will chime in, however here's a stab.

From what I've read from other posts, 1.6 ratio rockers may or may not bolt in with mods. It depends on your cam. If you have problems it will be with the pushrods rubbing against the heads as they travel through the increased stroke. From what I have seen, if you have a relatively stock cam, you should be okay. If you go with full rollers, not just tips, you might also have to change your valve covers to a tall version.

SB Chevy's have 3/8" studs - I do not believe you have to change the pushrods.

I'm going to make this same mod fairly soon, so I'm interested to see what others have to say. Check out Vette Magazine, they ran an article this month concerning roller rockers.

David

xrated

I would go for roller tipped rockers only. Comp Cams Magnums most likely. My cam is fairly stock so i dont think ill have a prob with bottoming out the springs or anything.

Ganey

Comp Cams makes 1.52 & 1.6 roller tip which fit under stock covers. The heads need clearancing for 1.6 which were really made for tuning. Get the Louis tool to clearance. You should give your cam specs. or figure lift, max. safe lift is .460. Stock push rods are fine.

:cool:

MikeC

Make sure that with that extra lift, your valve springs don't go into coil bind.

remember a .440"lift cam with 1.5 rockers jumps up to .469" with 1.6 rockers

@.469" you are starting to get into a close call situation(coil bind) with stock springs.


[Modified by MikeC, 7:26 AM 2/14/2002]

82 Super Vette

The standard GM 1.5 rockers are not really 1.5 they are 1.4? so you may be happier with the comp cams 1.52 without all the extra work. Ganey, can you tell him the exact specs of the stock 1.5 GM rockers and if there is any clearance problems with the 1.52's?

Cruise on!!! :chevy

Pete79L82

1.6 rockers will move the pushrod closer to the stud. This may cause a rubbing problem on some but not all heads were I have the red arrow. If it rubs there then you use a Louis tool to elongate the hole for clearance. If it does not rub you don't have to do anything. You still have to check for coil bind or valve seal interference. Generally if you have the stock cam this won't be a problem,




[Modified by Pete79L82, 11:19 PM 2/14/2002]

xrated

thanks guys.

What is a louis tool? and do i need to pull the heads to clearance the pushrods? The cam is stock and i dont really want to pull the motor just to change the cam. Im thinking ill get some 1.6 rockers and then if they dont fit ill pull the heads and get them worked over.
Will larger valves help my power output? With the stock cam is it even worth doing? I would shave them as well to get the comp ratio up a bit.

Corellian Corvette

Xrated

I just did this exact swap last weekend! I put 1.6 ratio roller *tipped* rockers in my '73 sb. I know that the full rollers are much better from the standpoint of reducing friction, but I wanted to retain my stock valve covers so I went with the roller tips only.

Bascially, I've heard that with stock cam and with stock heads, 1.6 ratio will fit fine. If you have an upgraded cam, or different heads, then you may run into some bind problems as mentioned above. And you can't clearance the heads with them on the car or you risk getting particles down into your pistons.

From what I researched, the stock rockers are 1.46 or so, and usually are not consistent from rocker-to-rocker. You gain a little performance going to 1.52, and it mostly depends on the condition and consistency between your original rockers. You will pick some noticeable increase going to 1.6, as my behind can personally attest to! :)

Putting them on is a breeze, and they can be adjusted really quickly with the car running.

Honestly, I think it was one of the best, easiest and cheapes mods I've done to my engine.

xrated

what brand of rockers did you put on?

Ganey

Stock vary so I indicate that w/ about so stock are about 1.47. No.

You need to state which 350, trans. & gears. A cam will help you the most. A cam can make a day & night difference. It can make your car run like a CORVETTE.

:cool:

Aaron-74

I just bought some 1.6 magnums yesterday. It there anyways to test ( I have my heads off my car) if they will rub at all?

what is a Louis tool?

Pete79L82

a Louis tool is a hardend steel insert that goes in one side of the push rod hole so that the hole can be drilled offset from its orignal location. Most cam makers sell them. It cam be done on the engine but you have to use a good vacum cleaner to collect the chips while you are drilling.


[Modified by Pete79L82, 6:41 AM 2/15/2002]


[Modified by Pete79L82, 6:41 AM 2/15/2002]