[lfdsteve]

If I’m running the old version of Round port E head with the cam in my signature, all things being equal:
1. Would the E head take a 1:65 rocker right out of the box. I have seen opinions both ways on the e head guide holes.
2. Is it even worth it for a street driven car with this cam?
Looking for a
Simple bolt on project to make me feel like I am a car guy but really don’t want to get into grinding and pulling the heads ect.
Wide open question I know but was just interested in opinions.
Thanks

[25stevem]

The addition of 1.65s which would give you .562” lift should be worth some power for you.
With your Tri-Y headers you should run the 1.65s on both intake and exh.
You will need new push rods to get the geometry right, but you will have no rubbing issues as with iron heads.

[Goatracer1]

I bought a set of early E round port heads brand new and used a set of 1.65 rockers and the push rods kept bending. The engine builder ( a well known Pontiac guy) tried several times to fix the problem before finding out the push rods were hitting the holes in the heads. He enlarged the holes and fixed the problem. I would check the clearance at full lift before saying everything is ok. I was not using a mega lift cam by the way.

[b-man]

I’ve always read it here and consider it by now to be pretty much common knowledge that E-heads need the pushrod holes ground for clearance in order to use 1.65:1 rockers.

It may be that in some cases you won’t need to but in most I’d say removing the heads and doing the work needed for proper pushrod clearance is necessary.

[77 TRASHCAN]

P-Dude stated here, long time ago that E-heads needed grinding for clearance, Kauffman heads did NOT...

[25stevem]

It depends a lot on your lifters. If your running a roller type lifter which are way taller then a non rollers then you may not have to..

[lfdsteve]

Thanks for the replies guys! Sounds like either way it would need to be checked, which should go without saying…
Have a great evening

[West Coast GTO]

If you go to Butler and look at there Edelbrock 87 cc round port heads, they give you this option:
BP/Edelbrock 61529 Complete Heads

Our Heads feature Edelbrock bare casting cores with all machine work done in our head shop. They are fitted with Ferrea Valves, new guides, Comp Cams Springs, Comp locators, Comp Retainers and Locks. They can optionally be slotted to accept 1.65 rockers if needed.

[Cliff R]

Too many variables to provide the correct answer. None of these aftermarket rocker arms are even patterned exactly the same.

Cam base circles vary some, lifter height as mentioned. Were the heads assembled with stock length valves, or longer valves?

For sure don't ask anyone, mock things up and see if you have enough clearance. My guess is that you will with a HR cam set-up.

The rocker arm change will provide a few degrees of effective duration and lower vacuum at idle slightly, plus push the power range up some. Going from 1.5's to 1.65's is just like small cam change. So if your aren't lacking on lower end power, making good vacuum at idle and want a little more upper-mid range and top end charge you will find it when going to 1.65 rocker over the 1.5's.

You also need to verify that you have the clearance for the additional lift. How much room to "coil bind" on the springs? Clearance from the bottom of the retainers to the valve guide seals? One can quickly get into troubles in those areas as well as lift increases quite a big with the high ratio rockers..........Cliff

[78w72]

FWIW, i called edelbrock to ask about this for my stock E-heads & they said these heads will need the p/r holes elongated for 1.65 rockers on most cams/combos. but as others have mentioned, there are variables where it may work but should be checked first.

if the heads are on the car & you dont want to pull them, it would be an expensive experiment to buy the 1.65 rockers & new pushrods & install them just to find they dont work without elongating the holes. all that for minimal power increase on a purely street engine is probably not worth the hassle or cost. you have a nice combo already, so unless you really want or need a small increase in power its probably best to leave it alone... spend the $$ on something else to make you feel like a car guy.

[lfdsteve]

Originally Posted by 78w72

FWIW, i called edelbrock to ask about this for my stock E-heads & they said these heads will need the p/r holes elongated for 1.65 rockers on most cams/combos. but as others have mentioned, there are variables where it may work but should be checked first.

if the heads are on the car & you dont want to pull them, it would be an expensive experiment to buy the 1.65 rockers & new pushrods & install them just to find they dont work without elongating the holes. all that for minimal power increase on a purely street engine is probably not worth the hassle or cost. you have a nice combo already, so unless you really want or need a small increase in power its probably best to leave it alone... spend the $$ on something else to make you feel like a car guy.

Yep. Thanks!
After reading this thread I will pass. It goes from stoplight to stoplight anyway, never really need to spread its wings.
I think I will pick an easier “car guy” project and purchase a vintage air system
😵*💫
Happy spring!