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#1
04-20-2021, 10:01 PM
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KRE D-port 505 dyno
Darby (Grandville) sent me his heads to see if we can make some more steam with his combo. Everything stayed the same and only the heads were done. We did do some manifold mods last season but it didn't show any real gains. I tweaked the cross sections on the intake and exhaust, kept the 45 degree seats, and valve sizes went from 2.19/1.66 to 2.2/1.7. Head flow was very close. Best port was 345 cfm before. Best port 355 after. They are still a standard port running 5/16 pushrods, 1.65 rocker and pac springs with 605 open and hollow stem intake valves. Darby has some more tuning in the car to do. I think there is 5 or 6 more hp to be found. Look at the before and after sheets on 92 octane. He also tried some Q16, the last sheet.
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| The Following User Says Thank You to blaktopr For This Useful Post: | ||
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#2
04-20-2021, 10:05 PM
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Great job blaktopr! Gains like that don't come easy at that level. You have to work for every positive horsepower and it's easy to go backwards.
Last edited by PAUL K; 04-20-2021 at 10:11 PM. |
| The Following User Says Thank You to PAUL K For This Useful Post: | ||
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#3
04-20-2021, 10:11 PM
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Thanks. We were under the target "peak hp" but the rpm range target was met and then some. Holds on well past peak. Darby is going to play with collectors and has a shear plate to try too at the track.
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#4
04-20-2021, 10:14 PM
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Anxious to see the results.
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#5
04-20-2021, 10:24 PM
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Anyone have issue with the oil pressure up there?Tom
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#6
04-20-2021, 10:27 PM
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Oil filter issue.
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#7
04-21-2021, 07:53 AM
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I see you switched to the SV1 carb for the last pull. Were the gains on that pull due to the carb or the Q16 fuel?
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#8
04-21-2021, 08:22 AM
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Quote:
__________________
Darby 74 Grandville 2Dr 455 c.i 4550# 2011 1.60 60 ft,7.33@94.55-11.502@117.74  2017, 74 firebird -3600 lbs (all bests) 1.33 60 ft, 6.314@108.39 9.950@134.32 M/T 275/60 ET SS Drag Radial 2023,(Pontiac 505) 1.27 60 ft, 5.97@112.86, 9.48@139.31.... 275/60 Radial Pro's |
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#9
04-21-2021, 10:27 AM
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Because of the small-diameter 5/16" pushrods to help with flexing have you opted to use pieces with a thicker wall ? Example 0116" -0118" thick wall.
.
__________________
'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 |
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#10
04-21-2021, 10:38 AM
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Quote:
__________________
Darby 74 Grandville 2Dr 455 c.i 4550# 2011 1.60 60 ft,7.33@94.55-11.502@117.74 2017, 74 firebird -3600 lbs (all bests) 1.33 60 ft, 6.314@108.39 9.950@134.32 M/T 275/60 ET SS Drag Radial 2023,(Pontiac 505) 1.27 60 ft, 5.97@112.86, 9.48@139.31.... 275/60 Radial Pro's |
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#11
04-21-2021, 10:58 AM
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OK.
Darby, I'm not suggesting there is anything wrong, only that a thicker wall section pushrod will help with deflection. Flex in the valvetrain means less valve lift and less airflow into the cylinder. "With a stiffer pushrod column, increased valvelift should be able to be measured statically in applications using a lot of spring pressure. The higher the engine speed the greater the increase will be at running speed. Keep in mind that by increasing wall thickness to a pushrod column does add strength, the percentage of increase is very small. The large gain in column strength comes from increasing the pushrod diameter." "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." http://mantonpushrods.com/tech-info/facts/ And great numbers, congratulations. .
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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.; 04-21-2021 at 11:03 AM. |
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#12
04-21-2021, 11:46 AM
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Steve these are the thick butler rods .116 wall it’s all I run since I can’t use a 3/8 rod
__________________
Darby 74 Grandville 2Dr 455 c.i 4550# 2011 1.60 60 ft,7.33@94.55-11.502@117.74 2017, 74 firebird -3600 lbs (all bests) 1.33 60 ft, 6.314@108.39 9.950@134.32 M/T 275/60 ET SS Drag Radial 2023,(Pontiac 505) 1.27 60 ft, 5.97@112.86, 9.48@139.31.... 275/60 Radial Pro's |
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#13
04-21-2021, 11:56 AM
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Got it, good deal.
That was what I was asking about, using a thicker wall 5/16" pushrod.
__________________
'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 |
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#14
04-21-2021, 02:47 PM
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#15
04-21-2021, 03:21 PM
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Quote:
__________________
Darby 74 Grandville 2Dr 455 c.i 4550# 2011 1.60 60 ft,7.33@94.55-11.502@117.74 2017, 74 firebird -3600 lbs (all bests) 1.33 60 ft, 6.314@108.39 9.950@134.32 M/T 275/60 ET SS Drag Radial 2023,(Pontiac 505) 1.27 60 ft, 5.97@112.86, 9.48@139.31.... 275/60 Radial Pro's |
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#16
04-21-2021, 03:22 PM
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#17
04-21-2021, 05:41 PM
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You do know 11/32 are a option also?Tom
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#18
04-21-2021, 05:42 PM
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#19
04-21-2021, 06:26 PM
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Quote:
How wide is your port at the push rod punch? Stan
__________________
Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm |
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#20
04-21-2021, 07:11 PM
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Some good gains.
What cam? |
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