# 1.65 Rockers



## Tim68 (Dec 1, 2019)

Anyone install 1.65 ratio rockers on heads with valve skirts?


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## PontiacJim (Dec 29, 2012)

Valve skirts? You mean "oil shields"? Should not make a difference as long as your lift is not crazy. You can always test fit a rocker arm and rotate the engine over and measure the clearance.

Did you clearance the pushrod holes in the head to make sure the pushrods don't bind and bend? Stronger valve springs? ARP Big Block rocker arm studs?


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## Tim68 (Dec 1, 2019)

PontiacJim said:


> Valve skirts? You mean "oil shields"? Should not make a difference as long as your lift is not crazy. You can always test fit a rocker arm and rotate the engine over and measure the clearance.
> 
> Did you clearance the pushrod holes in the head to make sure the pushrods don't bind and bend? Stronger valve springs? ARP Big Block rocker arm studs?


Jim,
I have been a member here for a short time and find that you share your experience with everyone no matter how trivial it may be.
Thank you for your contributions.
I have not yet taken the plunge to purchase the rockers. Hoping that I can get input to be sure it will work.
Actually I have not even removed the valve covers but assumed that the valve springs would have what I call skirts and assumed that they would potentially be an issue if I added lift to the valves.
I have the original 2bbl heads #14 with the original cam and lifters. I am trying to avoid getting into the engine but would like to give it a little more “fun factor“.
Your thlights?


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## PontiacJim (Dec 29, 2012)

Tim68 said:


> Jim,
> I have been a member here for a short time and find that you share your experience with everyone no matter how trivial it may be.
> Thank you for your contributions.
> I have not yet taken the plunge to purchase the rockers. Hoping that I can get input to be sure it will work.
> ...


OK, cool, more info which was needed. I would not use the 1.65 rockers as a means to get additional lift. The 2 Bbl heads are the low compression, small valve heads.

They will have the press-in "bottle neck" studs which will be your biggest drawback. The 1.65 rocker arms move the pivot point where your pushrod fits closer in towards the rocker arm stud. What this will do is put a lot of side load on an already weak point on the bottle neck stud. The additional side loading may break off the rocker arm stud AND it could also cause a press-in rocker arm stud as found on your heads to pull out.

The next consideration is that the 1.65 ratio lift actually accelerates the opening of the valves (and closing). The problem here could be weak or insufficient valve spring pressures and at higher RPM's as you wind out the engine, the springs may not be strong enough to hold the valve closed when it hits the valve seat in the head to which it seals. What it can do is actually bounce off the valve seat rather then close nice and tight. The engine will act as if the lifters were pumping up and run poorly or even give you some backfiring if severe enough at higher RPM's and you might think that the problem was something else and not consider it was the valve springs.

With the smaller valves, I don't think you will really gain much by simply holding them open higher. You would be better to go with a cam of the same lift (which all Pontiac cams have with exception of the "744" and "041" cam) and use a cam having more duration than the cam in there now. My source book says the factory cam for the 265HP 400 is the "254" cam.

The 254 cam has a duration of 269Int/277Ex and not much lift on the intake valve - .374", with the exhaust being .406" lift. Not much of a powerhouse. Most all low compression engines in the 8.0-8.6 range use the 254 cam.

The next up cam choice would be the "066". Duration is 273Int/282Ex, Lift .406" on both Int/Ex. This would work as it has more duration and lift on the intake and will work with your springs.

The next up "067" would not be a good choice as it would probably give you a "soft" responsive engine in the lower RPM's with the 8.6 compression as longer duration cams (and wider Lobe Separation Angle -LSA) have a tendency to bleed off cylinder pressure at lower RPM's. The longer duration of this cam will also move your HP/TQ band higher up the RPM scale.

So my recommendation if going with a factory cam would be the "066" and add a Q-jet and intake, good flowing exhaust, and dial in timing and distributor advance curve.

You could also go with an aftermarket cam that will build up a little more cylinder pressure, but in doing this, and not knowing the condition of the engine, you could have ring seal issues if your cylinders/rings are worn, and you will also be applying more down force/pressure on the crank bearings and if marginal or worn, could accelerate the wear.

If at a later time you want to get into the engine, you can add larger intake valves, do a 3-angle valve job, add screw-in rocker arm studs/poly locks, clearance the pushrod interference points on the head so as to use 1.65 rockers, new valve springs, and do a general rebuild of head. This would then give you a nice set of hi-performance iron heads and then you could make a better cam selection based on compression ratio and the RPM range you want to run with.

Again, what you call valve spring covers are what Pontiac calls "oil shields." Some people will remove them, others will keep them. It does depend on total valve lift, and I have read that if you use the Viton valve guide seals that they should be removed so as to put some oil on the valve stems because the Viton seals work well and with the oil shields installed, will not let enough oil to splash on the valve stems and ultimately they will be too dry and can lock the valve up in the valve guide. Cannot confirm this, just something I read, but also something to consider and talk with the engine builder.

I used the oil shields on my 7K3 heads that I went through. Used bronze valve guides and Viton valve seals. After reading about the oil shields and Viton valve seals, I am going to ask my engine builder about it. He told me the springs I installed should be good for a cam lift up to .600", not that I am going that big. So if the oil shields were going to be a problem at that high of lift, I don't think he would have installed them.......but I will definitely take some measurements and rotate the engine over with cam/lifters/pushrods installed and watch the rocker arm action as it compresses the valve springs.


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## Tim68 (Dec 1, 2019)

Awesome information. I was hoping to avoid a new cam and lifters. But while I have the engine out might as well. Sounds like it would be a good idea to go ahead and pull the pistons and do a rebuild to avoid issues down the road. Will the larger valves fit in these heads or should I find some better heads?
Thanks Jim


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## PontiacJim (Dec 29, 2012)

Tim68 said:


> Awesome information. I was hoping to avoid a new cam and lifters. But while I have the engine out might as well. Sounds like it would be a good idea to go ahead and pull the pistons and do a rebuild to avoid issues down the road. Will the larger valves fit in these heads or should I find some better heads?
> Thanks Jim


Everything depends on your budget. A complete rebuild could cost you around $4500ish depending on options. The more you can do, the additional savings.

You are going to get different opinions on the heads. First, any head you get/use, have it cleaned and magnafluxed for cracks. You don't want to invest a dime more should they turn out to be bad.

You already have the #14 heads - so no costs there. Buying another set of later heads with 2.11" intakes and screw-in studs will have to be added into the other costs to rebuild them. So a saving advantage with the #14 heads.

You could use your heads and install larger 2.11" intakes. Your machine shop will do this. They will have to open the throat with a cutter and then fit the valves and do a valve grind. This will give you fresh seats.

If you buy heads already having the 2.11" intakes, you will want to make sure that the valve seats are good and have not seen a couple of grindings which can sink the valves - you need a specific seat margin which your machine shop will know about.

In case #1, you will have to buy new valves. In case #2, you may be able to regrind the old valves - if they fall within spec. But, they are old.

New Ferrea stainless steel valves are about $90 a set. For $90, you get new and better valves. There are the longer RA IV valves which with matched springs, allow for a higher lift depending on how big a lift on the cam you want to go. You can also get the stock height valves as you now have, just a tad bit shorter than RA IV, but note that you will have to buy new pushrods with the longer RA IV valves. If your budget says "nope" then go with the stock length as you now have. Here is RA IV https://butlerperformance.com/i-244...alve-setfer-f5143-8.html?ref=category:1400522

A factory hi-po head will have the 2.11" intakes and screw-in rocker arm studs. You won't use the factory bottleneck studs for any good high lift cam - you will go with the ARP 7/16" Big Block Chevy rocker arm studs and poly locks. You unscrew your bottleneck studs from the factory hi-po heads and replace with the ARP studs - pretty simple.

With the #14 heads, you would buy the ARP screw-in studs specifically designed to replace the press-in Pontiac studs. I don't know if the rocker arm stands will need to be spot faced to get them flat prior to the machine shop cutting threads down into the stands for the screw-in studs to bolt in to. Again, fairly straight forward for a shop to do. In both cases, ARP studs. A little extra cost on the #14 heads if the rocker arm stand need to be milled flat (I have read both accounts where "no they don't" and "yes they do.") and tapping the press-in holes to accept the screw-in studs.

I would also install new exhaust valves in either head - so same costs there. The 1.66" exhaust size will work fine, or you can size up to 1.77" but will add additional costs in opening up the throats for fit.

My guess would be that either head will need new valve guides. Never knurl valve guides as this is a quick fix, but not one for long term if you plan on keeping the car. Some shops will use a cast iron valve guide to replicate the factory cast iron head and then hone to fit the valve stem. A better upgrade is the bronze valve guide. You save a few dollars on the cast guide, but both will require insertion & sizing - so no savings on installation as costs will apply the same to either heads.

Valve springs will be selected to match the cam lift.

Valve Seals. The Ferrea valves do not have a second ring/groove for factory type O-ring seals. So you will need to use a seal that fits on the valve guide which means the valve guide will have to be machined to accept these. Viton valve seals work best. Not a big operation. This generally will also mill down the guide and provide more clearance between the bottom of the valve spring retainer and top of the valve guide - so that could be a plus with bigger lift cams. Butler explains and provides examples: https://butlerperformance.com/n-13487-pontiac-valve-stem-sealing.html 

You will want a 3-angle valve job. Porting/clean up of the ports would be extra. I did my own, but have the tools and experience in doing them. Now I don't know how good a job I do as i have never flowed a set. I may have made them worse! LOL My 7K3 heads ran me about $1200 to have rebuilt with me doing the porting/bowl work. Here is a set ready to go out the door and flowed, and not too bad a price all considered: Nitemare Performance | Custom-Ported Pontiac Cylinder Heads

Some will say you need to add hardened seats. Note on the Nitmare heads, no hardened seats are added. I questioned the owner about this and he said he did not install hardened seats on any of his heads as the Pontiac heads were not designed for them. Instead, he uses a gas additive, Driven, that helps to lubricate the valves/valve seats and provide a slight more octane. Said he has never had a problem.

So you have options, but in the long run, I think there will be little difference in savings in buying another set of heads and rebuilding them, using our #14 heads and rebuilding them, or save the grief & time and purchase a ready to bolt on set of heads for a little more $.

Don't select pistons until you know what your actual head chamber cc's are. You will match your piston dish/valve relief cc's to the head cc's to arrive at a streetable compression ratio of what I feel is 9.0-9.3 for iron heads (unless you live at a high altitude and can go higher compressions). This will typically mean a custom forged piston. You also want a forged connecting rod, if nothing more than the lesser expensive forged I-beam. You will also have to balance the engine.

So you want to do the research and have an idea of what you want out of the car and for what purpose you will be mostly driving it as - street crusier, local around town, highway, street/strip, or other. You then have to take into account the HP/TQ you may be adding to the drivetrain and what upgrades will be required. Many forget about this, so it can cost more $$$ to be able to handle any big HP/TQ increases.


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## Tim68 (Dec 1, 2019)

PontiacJim said:


> Everything depends on your budget. A complete rebuild could cost you around $4500ish depending on options. The more you can do, the additional savings.
> 
> You are going to get different opinions on the heads. First, any head you get/use, have it cleaned and magnafluxed for cracks. You don't want to invest a dime more should they turn out to be bad.
> 
> ...


Pontiac Jim,
Thanks for the information. I will be reaching out to Nitemare next week. #16 heads and RA exhaust with 2 1/2” pipes. I will wait till I get bottom end to the machine shop to decide what I will do there.


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## BearGFR (Aug 25, 2008)

Tim68 said:


> Pontiac Jim,
> Thanks for the information. I will be reaching out to Nitemare next week. #16 heads and RA exhaust with 2 1/2” pipes. I will wait till I get bottom end to the machine shop to decide what I will do there.


Late to the party, but....

If you're considering a cam swap anyway, you might check with Bullet Cams - they are what the old "Ultradyne" morphed into and have their lobe designs - very good ones. That's what I'm running in my car right now. It's a solid roller and makes .620 lift at the valves _after_ compensating for what you "lose" due to valve lash, and it does that with 1.5:1 rockers no less. I'm told they are the largest lobes that can be physically installed into stock cam bearings. I wanted to "go back" to 1.5:1 rockers and take some stress out of the valve train after having a very "unfortunate" experience on the 2016 Power Tour. The previous build (and that one ran 11.80's at the track) ate a rocker arm going into Wichita KS and caused us to miss the rest of the tour and end up having to rent a U-Haul rig to trailer it home. That experience motivated me to see if it was possible to get the same (or better) performance with 1.5:1 rockers. It was. The engine now has all Crower parts on the top end including their High Pressure Pin Oiling (HIPPO) standard height cutaway roller lifters and their stainless steel full roller rockers, connected with Smith Bro's, thicker wall pushrods. Another benefit of the Ultradyne lobes is their exhaust valve closing ramps are "gentler" than a lot of the others and don't slam the valve shut as hard. This cam is quite a bit hotter than the previous one and does it with less stress on parts to boot. My previous cam, also a solid roller, was from Comp - 236/242 @ 0.050, 110 LSA, installed at 106 ICL, and made .600 net lift at the valves after accounting for lift --- using 1.65:1 Scorpion aluminum full roller rockers. This one from Bullet: 251/257 @ 0.050, 110 LSA, ICL 106, and makes .620/.622 net lift using 1.5:1 stainless steel roller rockers. 

It doesn't apply in my case because of the aftermarket heads I'm running, but another benefit with 1.5's is that you don't have to worry about needed to elongate the pushrod passages in the heads so that the pushrods don't rub, like you do with converting normal D-port factory heads to run 1.65's.

FWIW

Cheers,
Bear


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## Old Man Taylor (May 9, 2011)

If you ever plan on running 1.65 rockers, you need to make sure your heads are clearanced. More meat needs to be removed at the top of the pushrod hole as the pushrod has moved closer to that location.


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## Tim68 (Dec 1, 2019)

Old Man Taylor said:


> If you ever plan on running 1.65 rockers, you need to make sure your heads are clearanced. More meat needs to be removed at the top of the pushrod hole as the pushrod has moved closer to that location.


So I have decided to stick with roller 1.52
thanks for response as they have helped me from making a big mistake


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