gruveb

1.6 rockers on a 305 (L69) 58cc combustion chamber and a Comp Cams XE-262 cam.......would there be enough clearance?

Also, would 1.6 ratio rocker arms fit under stock center bolt valve covers?


I'm looking for the specs on that cam, but I can't find it. I think the lift is like .460 ......as soon as I find it I'll post it. It's a popular cam so someone probably knows off hand.

ME Leigh

I sure wouldn't run it with stock springs! I'm not sure about the stock valve cover interference but i do know some center-bolt VC's have problems.

gruveb

I definitely don't have stock springs.

RB83L69

Interference would depend on what rockers they are. In general, 1.6 rockers fit better than 1.5s of the same design, because the side toward the push rod is shorter. But, most roller rockers have a much wider trunnion than stock, and the centerbolt hold-down thing won't go between them; and the PCV oil baffles often won't either.

You'll have to be a little more specific.

gruveb

Would there be enough valve clearance with the extra lift?

I was thinking of these 1.6:1 or

this 1.52:1

Both are the same price.

RB83L69

Yes those should fit in the VCs. There should be no interference with the guides with the 1.6s.

That combo will give you right at .500" of lift though; make sure your springs are adequate.

gruveb

Thanks.

F-BIRD'88

If your heads have pushrod slots in the heads you may have to lengthen the slot for 1.6 rockers. The pushrod is moved closer to the stud with a 1.6 rocker. You use a drill and a "Louis Tool"
( special drill guide) to lengthen the slot. The old pre 87 305 heads have this slot. The other issue is you may not have enough clearance between the retainer and seal on the guide at full lift with the additional valve lift a 1.6 rocker will have.

jmnjn

Could i use the stock springs on L98 Aluminum heads with 1.6 rockers? What would happen?

gruveb

I wouldn't do it.

jmnjn

What would happen, I am unfamiliar in this area. I figured i could buy some rollerrockers 1.6 ratio and gain a bit more lift. Would the springs crack?

RB83L69

Here's a pic of what happens. https://www.thirdgen.org/techbb2/sho...hreadid=169253

Notice the broken spring. That's what happens from overstressing the valve springs. Notice the bent valve, broken piston, etc. Those are the results, after the spring broke; the valve was free to fall down into the cyl, where it got smacked by the piston.

Is it worth the risk? Personally I don't think so. Valve springs are some of the cheapest insurance you can buy.

jmnjn

WOW! Thanks for that info..... I am definitly going to change out the stock springs. What info should i go by when choosing the valve springs? IS it just lift, or are there other aspects i should know?