#21  
Old 12-10-2021, 11:59 AM
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Originally Posted by jhein View Post
That is if I can find a Forged crank. It looked like Butler had them but they called me and said they were out of stock and no ETA. Summit had a ETA of 2/16/21 on their site so I ordered one. We're not planning on starting until March so we'll see.

I don't know about 1.65 rockers. That's already a fairly aggressive cam don't you think?
If it were me, go with the 1.65 rocker. I run the same cam in both of the 461's in my '78 S/E and 1970 GTO. Both are running round port e-heads. If you are using the stock valve covers they will have to have a double gasket to clear.

I run the 1.65 roller rocker on the 433 in my '70 T/A. They have the the double stack since I'm running the stock chrome valve covers. Using 614 factory cast iron heads.

Hope it helps.


Last edited by napster; 12-10-2021 at 12:09 PM.
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  #22  
Old 12-10-2021, 01:50 PM
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Just got off the phone with Eagle and they are saying the forged crank should be available by late Jan-early Feb and they feel confident about that. So that's good news. I have it on order from Summit and Eagle said that Summit will likely get them before someplace like Butler so that's also good.

So back to the cam thing. I was looking at the Comp Cam XE288HR. The Butler guy suggested their BP/Comp custom grind which is the same as the XE288HR but with a slightly wider LSA. Both are 288/294, 236/242, .521/.540 but he Comp cam has a LSA of 110 and the BP is 112. He says the benefits are better idle vacuum, smoother idle and overall lower RPM driveability. Just wondering what people think about that.

As for the 1.65 rockers, what is the reasoning for that? Just more "free" power, or other benefits? I feel like if I'm in the 500 HP/550 tq range that's going to give plenty of performance for how I'm using it.

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  #23  
Old 12-10-2021, 02:27 PM
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I run the off the shelve XR288HR on my ’78 SE. I have run into a problem with the brakes. It feels like there is not enough vacuum. It has a four wheel disc brake system and four pistion calipers all the way around.

However, I run the same engine in my 1970 GTO with the same brake system and have no problems with the brakes. Stops very well. Go figure.

When it came to my ’70 T/A, I went with the Butler grind one step below the cam recommended by Butler for your 461. It is @ 112. The brake system is completely stock and have no problems. Stops on a dime. The brake system still has the original rotors and calipers. It has new brake pads. The rear drums are still the originals. The car only has 31K on it.

If you are wondering what the idle sounds like on the cars with the cams here are examples:

"78 S/E
https://www.youtube.com/watch?v=ZMS1LACZD0Y&t=54s
'70 GTO
https://www.youtube.com/watch?v=EoYVfvmtuX8&t=21s
"70 T/A
https://www.youtube.com/watch?v=AXveB8zehOw&t=50s

I use the 1.65 Roller rockers to get that much more out of the engine. If you feel fine with the 1.5 ratio, then by all means stay with it.

Hope this helps.

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  #24  
Old 12-10-2021, 02:45 PM
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Mine was Comp's HR288, vacuum was no consideration for me since I have manual brakes. My thought on the 1.65s was to take advantage of the aluminum heads flow for an easy power gain. One of my bud's has this cam with 1.5s in a 455/stock Edelbrock round ports/ headers and he is real happy with it.

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Old 12-10-2021, 03:42 PM
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Quote:
Originally Posted by napster View Post
I run the off the shelve XR288HR on my ’78 SE. I have run into a problem with the brakes. It feels like there is not enough vacuum. It has a four wheel disc brake system and four pistion calipers all the way around.

However, I run the same engine in my 1970 GTO with the same brake system and have no problems with the brakes. Stops very well. Go figure.

When it came to my ’70 T/A, I went with the Butler grind one step below the cam recommended by Butler for your 461. It is @ 112. The brake system is completely stock and have no problems. Stops on a dime. The brake system still has the original rotors and calipers. It has new brake pads. The rear drums are still the originals. The car only has 31K on it.

If you are wondering what the idle sounds like on the cars with the cams here are examples:

"78 S/E
https://www.youtube.com/watch?v=ZMS1LACZD0Y&t=54s
'70 GTO
https://www.youtube.com/watch?v=EoYVfvmtuX8&t=21s
"70 T/A
https://www.youtube.com/watch?v=AXveB8zehOw&t=50s

I use the 1.65 Roller rockers to get that much more out of the engine. If you feel fine with the 1.5 ratio, then by all means stay with it.

Hope this helps.
Yep, very helpful.

Am I correct that most of the idle sound we like comes from the duration and overlap rather than lift? If so I think that the 288 cam specs will do what I want with 1.5 rockers.

Both Butler and my builder think that cam will give enough vacuum for brakes. So I still don't see a compelling reason to pick one over the other.

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https://youtube.com/shorts/gG15nb4FWeo?feature=share
  #26  
Old 12-10-2021, 03:45 PM
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Quote:
Originally Posted by OCMDGTO View Post
Mine was Comp's HR288, vacuum was no consideration for me since I have manual brakes. My thought on the 1.65s was to take advantage of the aluminum heads flow for an easy power gain. One of my bud's has this cam with 1.5s in a 455/stock Edelbrock round ports/ headers and he is real happy with it.
Yeah, I see that the 1.65s are an easy, free power gain. But like I said, I think this motor will have plenty of power for me with the 1.5s. I guess that proves I'm getting old. As if I needed any more proof...

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https://youtube.com/shorts/gG15nb4FWeo?feature=share
  #27  
Old 12-12-2021, 02:22 PM
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Originally Posted by jhein View Post
Yep, very helpful.

Am I correct that most of the idle sound we like comes from the duration and overlap rather than lift? If so I think that the 288 cam specs will do what I want with 1.5 rockers.

Both Butler and my builder think that cam will give enough vacuum for brakes. So I still don't see a compelling reason to pick one over the other.
The answer to the duration and overlap question is yes.

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  #28  
Old 12-14-2021, 02:21 PM
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Good to hear you and Archie got it figured out.

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  #29  
Old 12-14-2021, 02:54 PM
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Good to hear you and Archie got it figured out.
Yeah, thanks very much for the recommandation. It seems to be working out well. Parts availability has been a bit of a struggle but, everything seems to be coming together. I even got Archie to laugh a couple times.

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  #30  
Old 12-27-2021, 07:33 PM
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OK, all the parts are in, including a Scat forged crank. Now I just need a fast forward button...

Can you think of anything else I may need? Maybe upgraded motor mounts or anything?

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  #31  
Old 12-28-2021, 01:21 AM
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Originally Posted by jhein View Post
Can you think of anything else I may need? Maybe upgraded motor mounts or anything?
Wider, stickier rear tires???

  #32  
Old 12-28-2021, 08:27 AM
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Quote:
Originally Posted by jhein View Post
OK, all the parts are in, including a Scat forged crank. Now I just need a fast forward button...

Can you think of anything else I may need? Maybe upgraded motor mounts or anything?
May consider changes to your fuel system. Qjet may need to be set-up, larger fuel lines, fuel pump, pusher pump.

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