#21  
Old 11-22-2022, 04:24 PM
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Quote:
Originally Posted by PAUL K View Post
Yeah.... You're wrong

The cam core can be taken care of. All that's left is a trouble free lifter. There's several options to take care of that.

I don't have enough time to cover the HR's issues but they stem from broken lifter bore, to ticking, with a bunch in between.
I wasn't aware there were good hft lifters, that's good to know.
I'm fully aware of issues related to hyd rollers

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Old 11-22-2022, 05:36 PM
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What about the Crower 60919

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  #23  
Old 11-22-2022, 07:26 PM
Formulas Formulas is offline
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To curb HFT issues use the lightest SS valves possible OE's are heavy, use low mass rockers and keep pushrods as light as possible, All this will allow you to run minimal spring pressures

is there any chance of getting a 80-85CC small valve 350 head? Slightly smaller valves and bowls should bring the torque curve in sooner and the higher compression than 6X4 will help that too...
just a thought

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Old 11-22-2022, 11:10 PM
Steve C. Steve C. is offline
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From Manton...

Do not be overly concerned about pushrod weight. The pushrod is on the slow moving side of the valve train. The additional weight of a heavy wall pushrod usually provides a much needed increase in valve train stability.


.

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Old 11-23-2022, 12:17 AM
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Can't compare a Chevy to a Pontiac, BUT!

A good friend of mine had a small block 400 built for his 1966 C10 pickup. .030 over, cheapest forged pistons available. Short rods. Early performer intake. 3310 Holley. And SMALL long tube headers (1-1/2" primaries).

Used a 268H comp cam (again not a XE cam). Made 300 HP, 400 ft/lbs on a Superflow dyno. My engine builder (here, same) always went with absolute net ratings, nothing exaggerated or fluffed up, just the truth.
This Old pickup weighed over 5000 pounds, but performed like a bat outta Hooterville!!!

I lost this good friend this past February. He sold his 66 about the time I was getting married in 1995. Another life lesson for me!!!

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Old 11-23-2022, 07:40 AM
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My RA3 with a melling 068, 400 turbo and 3.31's gets 17 mpg in my bird if I drive it nice at 70 mph. Plenty of long trips doing that over the last 25 years.
Has went a best 13.10 and a best mph of 106. Enough fun for a daily driver. An overdrive should put it well over 20 mpg if I ever decide to do that one day.

On a more radical scale, dad's road trip this past weekend in his 571ci gto with a 4l80e and 3.42's got him 15.89 mpg at 70 mph. Not bad for 720hp.
Overdrive and gear selection are key.

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Old 11-23-2022, 07:46 AM
Formulas Formulas is offline
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Quote:
Originally Posted by Steve C. View Post
From Manton...

Do not be overly concerned about pushrod weight. The pushrod is on the slow moving side of the valve train. The additional weight of a heavy wall pushrod usually provides a much needed increase in valve train stability.


.

who is overly ?? every bit helps my statement is correct and with minimum springs pressure like dead stock or weak stockers your much needed is out the window...

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Old 11-23-2022, 09:50 AM
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Quote:
Originally Posted by b-man View Post
I would do the Butler 067 hydraulic roller.

Running mostly at 2000 rpm this would be a great choice, will easily run somewhere in the 14s.
X2...however, for what it's worth, my '71 Formula with the stock 455HO (3.42 gears) with the 2801 cam (with a true 8.2 static compression) gets a solid 14 mpg at 65 mph (2800 rpm). My '70 Lemans with a 461 (3.08 gears and M-20 4-speed) with 9.5 static compression and a RAIV copy cam (Bullet) with 1.5 rockers gets a whopping 18 mpg at 65 mph (2500 rpm - damn fun car to drive), and my pure stock RAIII Formula (068 cam & 3.55 gears) gets a solid 16 mpg at 65 mph (2900 rpm). I'm not sure you can develop a hypothesis from this info, but they all seem to be fairly efficient on the highway. They all have 27" tall tires, btw...

Dennis


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Old 11-23-2022, 10:03 AM
Steve C. Steve C. is offline
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Formulas, you are correct. The situation here may not generate the interest in valvetrain stability. Just a tid bit here for presented interest.

Source: https://mantonpushrods.com/tech-info/facts/

Many as a norm go from the typical .080"-0.83" pushrod to around 0.118". I've never weighed the difference.

Cliff Ruggles statement on the subject:

"BTW, we are switching all of our engines over to custom thicker wall pushrods, as the .080" wall 5/16" units are flexing a bit too much for our liking with these increased spring pressures and heavier valvetrain parts we end up using these days"

But again, the caveat here, increased valvetrain mass and the resulting increased spring pressure is not in the cards here.


.

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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 )
Old information here:
http://www.hotrod.com/articles/0712p...tiac-trans-am/

Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine)
5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension
https://www.youtube.com/watch?v=qDoJnIP3HgE

Last edited by Steve C.; 11-23-2022 at 10:17 AM.
  #30  
Old 11-23-2022, 02:01 PM
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I think most of the examples are showing you can bump up performance quite a bit and not give up a lot on the efficiency at cruising speed. Especially with OD tranny’s or tall gears..

The right compression coupled with a well matched cam really helps also.

Jeff, I was think about what I mentioned on the hi-energy 268 in low compression 455s against the 068 and the 214/224 summit cam. That was wrong. The cam I recall adding a tad of fuel economy over those 2 cams was a 230/230 cam in a 455 HO, same cam family as a 268, just bigger. It was fairly shocking considering how much rowdier the cam is.

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