[Lifetime Goat]

My GTO does not run the way it should and my 17 year old wants to learn how to rip it apart and put it back together. So what the heck. I was running my 455, 64 heads, 71 HO intake and carb with an ultradyne 231/239 cam with headers. As most of you are aware that combo wants to hang out above 3000 rpm most of the time. I was considering going back to something like a comp cams 462H cam with RAIII exhaust manifolds so my kid could drive the street.Any thoughts on the cam swap? I run 3:55 rear gears.

[67 Lamnas]

Originally Posted by Lifetime Goat

My GTO does not run the way it should and my 17 year old wants to learn how to rip it apart and put it back together. So what the heck. I was running my 455, 64 heads, 71 HO intake and carb with an ultradyne 231/239 cam with headers. As most of you are aware that combo wants to hang out above 3000 rpm most of the time. I was considering going back to something like a comp cams 462H cam with RAIII exhaust manifolds so my kid could drive the street.Any thoughts on the cam swap? I run 3:55 rear gears.

If it were me, I'd keep the present cam and reassemble with a set of Rhoads lifters.

[Lifetime Goat]

I guess a more specific question is are there any new grinds out there that would make this more streetable for a young driver without losing too much power? I could keep the Ultradyne but I was just wondering?

[mchell]

that does not appear to be a whole lot of cam....should run fine.....elaborate on why you think its not running the way it should....

[Lifetime Goat]

A couple of things. First it has started to burn too much oil. It was rebuilt 5 years ago but I do not have a lot of hours on the motor. I have checked the compression and it appears to be fine. I am hoping it is in the valve train or seals. In addition the off idle is a little sluggish unless I get into the throttle with this combo. Since my 17 year old would like to drive it a little I was considering changing the cam to something a little tamer for a newer driver. Lastly he keeps asking me a million questions on what is going on underneath the chrome. So I am inclined to do an inspection anyway to see what is happening inside and possibly teach him something before he becomes unteachable.

[gearbanger]

I would put a hyd roller in it. You will be able to make more power than a hyd flat and you will never have to worry about wiping a lobe again. That is a good feeling. Also, you have a rare green light situation to spend money on your car that normally would be frowned upon by the sig. other. This is all for junior...money is no object. It's all about building the safest, most reliable machine to get him home safely at night. Heaven forbid it break down on him.

[Lifetime Goat]

Does it make any sense to put in a hydraulic roller cam for a mild street setup? what would you suggest?

[lust4speed]

Most important thing to add? ...a rev limiter. My first concern is turning a 17 year old loose in a good running GTO. You can set the limiter very low and let him know that it's set low. Something about knowing the engine's power is capped that keeps kids from exploring the far regions of performance. My son's car was the '65 2+2, and I had it set where it would run the quarter in 18 seconds, but still sounded great. After he graduated high school we kicked up the performance, and it's now a low 13 second 4,500 pound street barge. He never did figure out that I had limited the secondaries opening to a little less than half along with the rev limiter. Anyway, that was my small contribution to the safety of my kid when he was in the car and out of sight.

I would also be inclined to keep the cam if it shows to be in good shape. It's definitely broken in, and if it doesn't show wear I'd drop it back in. Just insure you don't mix up the lifters. If you are in the market for a new cam, then a hydraulic roller would be a good investment with all the flat tappet cam failures lately. You will still need to be at least 224/230° @ .050" with the 455, or it will sound stock.

[Lifetime Goat]

I got the rev limiter covered. I have one connected to the MSD and he asked my why it breaks up when it gets to 5000 rpm. I told him because the other chips are gone. You are correct it is tough to balance. But lets talk about the big kid, me, for a moment. A lot of people have been posting or sending me messages about bad lifters, valve jobs with too much clearance and loose seals. Is it really that bad that this items are just not that good off the shelf? I figured with all of this CNC stuff that we would be past this?

[lust4speed]

The cam/lifter mess is scary. You can add extra zinc and run the break-in according to the book, and still have failures. I believe it is all lifter problems, but there is that lingering doubt that we might also be getting soft cams. You eliminate the issue by spending the bucks and getting a hydraulic roller assembly. This goes back to my comment that if your old cam is good, I would trust it more than most replacements available today.

As far as bad valve jobs, that's purely operator incompetence - they're either in too big of hurry or don't know what they are doing. A good machine shop is going to have a valve machine that cost more than my first house, and a skilled operator to run it. You need to post your location and ask for local input on who is doing the best work.

If a valve stem has too much clearance, then it is going to wobble in the guide and this will lead to failure of the seal. Everything has to start with good machine work.

[Lifetime Goat]

Actually the theory that I was told was that valve jobs are being done with more clearance to compensate for todays fuel. That many valve to guide clearances are at .002 or .003 as opposed to a much tighter .001. I have no way to confirm but it does make some sense. In any event I will consider using the existing cam and making some other changes.

[runningbwdog]

HI,
I have a 462 in my 68 GTO with MT and 3.55 rear gears.
I put in a Comps Cam XE-268 cam. It has tons of low end torque. Can drive away on level ground without touching the gas pedal, just let the clutch out slowly. Once the clutch is fully engaged any exuberant gas pedal pressure will spin the tires.
Mike

[Lifetime Goat]

Did you put the cam in straight up or did you advance it? And are you using headers or cast iron manifolds?

[runningbwdog]

Hi,
I have #15 heads that have 1.96" intake and 1.77" exhaust valves. Stock log exhaust and cast iron stock intake with a CliffR Q-Jet. Dist was set up by SunTuned. Cam was installed straight up. Dyno says 464 ft/lbs of torque at 3200 RPM. Compression is 9.34:1. Runs well on 93 octane pump gas.
Mike

[lust4speed]

Originally Posted by Lifetime Goat

...that many valve to guide clearances are at .002 or .003 as opposed to a much tighter .001...

Acceptable stock intake clearance is .0016 to .0033, and exhaust clearance is .0021 to .0038 so I'm not too sure what the person was talking about that gave you the information. Clearances of .002 to .003 Would have been acceptable to Pontiac back in the day.

[Lifetime Goat]

I will find out soon enough. Next steps are to remove and disassemble and see what we have. Just had to explain to my son that we dont immediately put it back in the next day. Thanks all for the advice.