The push rods will spin harder when there is tension on them, and easier when there isn't. So depending on whether the lifter is the nose of the cam and opening a valve against spring pressure, the push rods will spin easier or harder. Valve noise can be from lots of sources. Worn rocker arms or shafts, or a lifter that leaks down too fast. IMO, people obsess about valve noise. The only engines that are dead silent are bone stock engines. Once you change to a higher performance camshaft, some noise is expected. Unless it is rapping away, and you can hear it from inside the car, I wouldn't worry about it. Do you have adjustable push rods?
8 They are not adjustable. The machinist who degreed my cam and assembled my heads checked preload and said everything was fine. They are the stock length original pushrods. I have aluminum rockers but iron shafts is this normal? I was happy to see how much oil was coming out of the driver side push rods. It barely oiled before the rebuild. The new front cam bearing must have made a big difference.
I think I will just plan on getting new rockers and shafts eventually. I scrolled back a few pages where I first mentioned the tick. Someone mentioned that Aluminum rockers get noisy when they are worn. But I'm not sure if that would effect the spinning rate of a pushrod. Ta sells a stock replacement. Is there any kind of performance option?
Ta has roller rockers. 900 bucks. Stamped steel are inexpensive. Yes the worn shafts with aluminum rockers can be noisy.
Does the $900 roller rocker setup work with the existing pushrods and is it a direct bolt on upgrade? how much horsepower gain is realistic and where will it effect the power range?
There was a silent recall on those aluminum rockers in 1976. They really don't make any noise until they wear into the shafts and you lose preload. Adjustable pushrods will get you exact preload, rollers are adjustable also, not much h.p. gain, just smooth & less friction, unless you go up in ratio. Your aluminum rockers are 1.55 ratio, 68-69 style are 1.59 & the stamped steel replacements are 1.5, so you will lose a bit of valve lift using the steels.
Machinist said preload was fine but I doubt he checked more than one. I will probably buy the stamped steel replacements later this year. Depending on how worn mine are isn't it possible that I might actually see an increase in lift with the new ones even if they are just the 1.5 And if not will the decrease in valve lift be a big issue? Will 68-69 work on my heads?
I would guess About a 2-5 hp gain with roller rockers on a stock engine, I still use them on my builds. On large cams there may be up to 10 hp gains.
You are right, your machinist probably only checked a couple. 68-69 have 3/8" radius ends. They (TA) sell hybrid pushrods, 3/8" on rocker end and 5/16" on lifter cup end. I've run adjustable Poston 5/16" on both ends for years with 68 rockers without any noticeable problems. The 68/69 are kindof expensive & hard to find....
If i go from a 1.55 to a 1.5 what kind of power difference am I looking at? I do know where there is a 69 wildcat 350 4 barrel. It's cheap.
Not enough to worry about. While you're waiting for snow to melt, you can pop rocker shafts off and physically look at how much wear the shafts have & the alum rocker's have on the underside. This pic shows severe wear...
No no. Not like that 1.55 vs 1.50 makes this happen: If the cam lobe is .349 tall--- .349 X 1.55 = .541 .349 X 1.50 = .524 The real difference is less than .02 hundredths, depending on the size of the cam lobe. So definitely less with your smaller cam lobes
Ive mentioned this to you before but please look at my cam card here. I've seen other cam cards on this site that say to degree intake to where its advanced. But mine says to degree to 110 for zero advance. A half dozen people on here told me to advance my cam and I asked my machinist to advance it but instead He degreed it to 109.5. He assured me it was right. And inline with the cam card. Am I misunderstanding something? I've read that this could potentially make a huge difference. I just feel like I'm always going to wonder. I've read that some cams have the advance ground into them...is that the case for mine?
I mentioned advancing cam to increase dynamic compression and lower end power, since your running lower static compression and small torque converter. It doesn’t look like there’s any advance ground into cam. I do not think cam is incorrect. Your not necessarily loosing power, as advancing cam does give up some top end to get more lower end.
There is no such thing as advance built into the cam, cam timing is cam timing. I suppose that in a PERFECT world, IF you installed a cam with a multi key way timing gear set, AND you set it on the zero (straight up) key way, AND when you degreed the cam, it came in 4* advanced, you could think of that 4* as built into the cam. We don't live in a perfect world of course, and that is why unless you degree the cam, you'll never know exactly how it went into the engine. There are "tolerances" in every part, the gears, and cam. I have been reading for years how various timing gear sets are off. Then cams don't get ground exactly right. It can all add up to some substantial error. Cams are designed to produce certain results when installed in a engine. The cam card tells you to degree the cam to a certain intake centerline to achieve those listed results. You can advance or retard a cam to modify those results. Advancing a cam makes the valve timing events occur sooner. It enhances low end at the expense of top end power. It closes the intake valve sooner which increases dynamic compression.
Opinions and suggestions needed. I have the option here in Iowa of 91 octane ethanol free or 92 or 93 octane but would contain up to 10% ethanol. I have gas station just a few miles from my house that offers 93 but contains ethanol. Walmart offers 92 with ethanol. I have avoided using any kind of ethanol fuel in this car so far. is there any reason not to run the higher octane fuel with the ethanol?
Stick with the non ethanol fuel whenever possible. The ethanol affects the shelf life of the fuel. Ethanol is corrosive and it absorbs water. During the winter months, this can be very important when you can't drive the car and the fuel has to sit for extended periods unused. In the Spring and Summer, I'll use the E10 93 as I am always putting more in, but over the winter, non ethanol fuel for sure.
