1.65 rockers on speed master heads
 

I bought a set of them a few years ago and may try them on a 408 I have. Has anyone had any areas using 1.65 rockers with 5/16 pushrods that hit? I'm going to mock it up this weekend.

https://forums.maxperformanceinc.com...65+speedmaster

Some info here. Let us know how yours do.

Murf

Due to the push rod cup in a 1.65 rocker being closer to the pivot point then a 1.5 rocker the push rod side of the rocker will sit about .080” closer to the top of the valve cover .
Since it starts off closer it will be closer at the max lift your running.

I mocked this up Tonite. I see no issues running 1.60 or greater ratio rocker. Actually 1.5 is to close to the intake side on these heads. I will have to clearance them.

1.5 pics

5/16 pushrod?

what method did you use to get your pushrod length? I've used the half lift method with good results. I would have expected the pushrod to be more in the middle of the hole vs outer wall. I had to buy the 2.3inch rocker studs to get the correct geometry with 1.8 installed height. I also noticed on mine I had to move the push rod plates around to center them the best I could.

Rocker Geometry
https://youtu.be/o5is9BsH5OU

5/16 pushrods.

I start the pushrod length long on stud mounted systems and keep shortening it till the pattern moves to the intake side of center. That gives me a starting point. I came up with 8.950 that is with comp retro lifters

Too bad there isn't any clearance for 3/8 pushrods

That's with 1.60 ratio. The plate could be centered a bit better

The alluminium will expand when the motor warms up giving more room.

GT

I'm going to move the hole towards the intake side about .100

Does anyone make a stamped steel 1.65 rocker?

Suggesting 1.5:1 is sufficient for the exhaust.

The butlers list 1.65 melling stamp steel rockers

Don't know how I missed that. Thank you!

I had the shop I use go over the heads. Springs were light pressure wise. Average 100 on the seat and 240 at .540. The valve job was decent and guides were fine. No metal shavings found anywhere. One head was about .002 off on the deck surface end to end. We moved the pushrod holes up to the valve cover rail for 1.5 clearance. Changed the springs for 130 seat and 350 open pressure. Removed shims and put in spring locators. Guide plates are available from speed master. There was room in the stack for over .600 lift out the box.

How many shims were under each side intake,exhaust? My HR setup had a bunch. I was almost wondering if they used the same spring and just added shims for seat pressure.

I have some extra E head guide plates form when I went to a shaft system was hoping they would work.

Pretty good stack of shims. I got the same impression on the spring situation. My rocker studs hit the installation tab for the helicoil also but I think I can break them off or shorten the stud