Head mods for 1.65 rockers

[KEV]

Hey guys! well i want to make this mod on my heads. warped in another post sated enlarging the pushrod holes .125". if im looking at the driver side head, which side do i grind on (side closest to intake or side closest to exhaust?)

also, do you need to go the entire length of the pushrod guide? what is the best way to do this? just use a drill bit?

thanks for the info

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Kevin Swaney
Gold '66 GTO, 389 4 spd with Trips
13.042 @ 106.64 mph

[KEV]

Hey guys! well i want to make this mod on my heads. warped in another post sated enlarging the pushrod holes .125". if im looking at the driver side head, which side do i grind on (side closest to intake or side closest to exhaust?)

also, do you need to go the entire length of the pushrod guide? what is the best way to do this? just use a drill bit?

thanks for the info

------------------
Kevin Swaney
Gold '66 GTO, 389 4 spd with Trips
13.042 @ 106.64 mph

[David Holmberg]

Kev, You open the rocker stud side. As the arm goes higher the pushrod will move closer to the stud. Each head is different, some need no mods, and some more than others.

[Old Man Taylor]

The old HO Engine Design book said to start at 1/8" enlargement tapering to zero at a depth of 1/2".

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Jim

[BVR421]

I dont think you ought to go grinding on them if the pushrods arent touching. From your post it sounds like you havent really determined if there is even a problem and if so where it is exactly. I hate to see you do a lot of work unnecessarily when a problem may or maynot be elsewhere.
You might want to s l o w l y rotate the motor a few degrees at a time checking clearances everywhere starting with the pushrod to head then check overall geometry and then retainer clearance at full tilt.
How much is the lift with the stock 1.5 rockers? Any danger of coil bind?
I hope it turns out to be just noisy rockers like many have reported.

[al]

Before you go doing anything...those heads have to come off before you go grinding. Secondly I had crane cam 165 roller rockers that where quiet. I then switched to HS 1.5's and swapped to a crane power max
cam and bingo...valvetrain noise. I believe the noise is due to the fast opening ramp on the intake lobe of the cam and the somewhat noisy HS. From speaking with different people they have all pretty much said the HS rockers are noisy,everything else being the same.
Check everything out well before you make any decisions. If your pushrods are rubbing,they will have noticeable scuff marks where they are rubbing on the heads.