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#61
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Ports size is part of it. They seem to work well on aftermarket blocks.
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#62
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#63
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How much compression and shift points? And rest of combo?
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Illinois Outlaw Gassers 6.27@107 9.97@131 |
#64
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Ports have had the pushrods moved, so ports are naturally larger still. Over 14:1 CR
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#65
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380 cfm? Cam?
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Illinois Outlaw Gassers 6.27@107 9.97@131 |
#66
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Whole point of post being to say that the KRE HP heads are a good alternative to the Edelbrocks. Even in smaller displacement engine combinations that have a higher level of development. These heads easily outpaced a very nice set of equivalent E-wide heads on a similar engine package
IMO, and as it should come as no surprise the short turn radius height improvement is an advantage. The motor is nowhere near matched to the car. Too many projects. Darby knows the story. |
#67
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And to be clear, I know this post started as a conversation about standard PR location KRE HP heads. In that context the KRE HP heads as cast IMO could offer an advantage over the E heads with the same combustion chamber size on an engine combination that required "more".
As Slowbird alluded to the increase in runner volume is largely as a result of the raised port. Which increases the intake runner volume. This does not equate to a larger CSA everything else being equal, only that the longer tract adds to volume. Other variables depend on valve diameter, bowl, etc. |
#68
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As cast the HP head already has a 0.200 Offset pushrod location on the intake.
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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 |
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#69
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If the only difference is actually the block itself, there must be a reason. Difference in the valve valve relief cuts? Maybe it's more due to anyone who spends the $$ to go aftermarket block is also not going to skimp on machine work and quality components. Don't know, but it would be hard to explain the block itself making more power with a certain head. Not saying it's not true - I have no experience either way - just hard to explain.
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Hoping to finish a project while I'm still able to push the clutch in.... 1963 Tempest Convertible (195-1bbl, 3-speed transaxle. 428 RAIV, 5-speed, IRS planned) Pictures |
#70
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Edelbrock heads with an off-set pushrod have been 8.0 at approximately 3300 lbs. with nitrous on a factory block short block.
Edelbrock heads with standard pushrod location have been 8.90 naturally aspirated at a similar weight on a factory block. Please list some times and weights of Hi-port heads on stock block combinations as asked in post 44. I am curious to see the all the extra power the hi-port will make on a factory block. Last edited by PAUL K; 09-09-2020 at 10:28 PM. |
#71
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I have a stock block 461 with High Ports in my 68 GTO. Bottom end has 4.155 ROSS pistons, RPM rods, Ohio forged crank and studded 2 bolt caps. Northwind and a 1050 Dominator. Used to have 78cc E-heads just cleaned up with 2.11/1.66 valves and a 2.3X1.2 intake opening. Had a Lunati solid roller 255/263 @ .050 .4176 lobes 109 LSA 1.6 rockers and about .650 lift. CR was about 10.8 used 93 pump gas. Best time was a 10.97 @ 122 mph at 3850 lb race weight. TH400 with 4000 stall FTI converter. 3.73 gears. Changed only the heads to 80cc High Ports with 2.4X1.2 intake opening otherwise as cast heads with 2.2 and 1.7 valves. Compression now 10.63. Couldn't match time with E-heads. Came close but couldn't run tens. Mostly 11 teens to 11.20's. Ran that mostly with the E-heads also. Changed cam to a Jones custom solid roller everything else the same. 316/320, 263/269 @ .050, .421/.412 lobe lift and 110 LSA. Lift is .658 and .640. Best time with this cam is 10.97 @ 123 mph with a 1.61 60 ft. Mostly runs 11 teens and 11.20's. Next thing to try is maybe a higher stall converter or more cubes? Was hoping for consistent 10's. I do have a Lunati 271/278 @ 050 solid roller I was thinking of trying.
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#72
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Last edited by PAUL K; 09-09-2020 at 10:30 PM. |
#73
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I like the more stall idea.
Maybe some intake work if it is stock. 3850 lbs is heavy. |
#74
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My HP head combo vs. the E head combo was .31 in ET quicker and almost 4 MPH faster in worse air. Similar combos and some variances, but then consider neither of these cylinder heads I have run have a "part number" that anyone can order. Hard to be objective accordingly.
No way to make the comparison you are suggesting in a fair manner. Gotta be at least 50:1 ratio of Edelbrock Pontiac non d-port headed combo sales to KRE HP heads to date. Just saying that the comparison is not as straightforward as it may appear on the surface. Last edited by ChiefCrazyCanuck; 09-09-2020 at 11:08 PM. |
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#75
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#76
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#77
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ChiefCrazyCanuck, yes they were both measured.
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#78
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#79
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The almost 2 tenths CR reduction from the HP heads would have some kind of effect. And you mention that the results were very similar from the Edelbrocks to the KRE HP heads generally speaking.
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#80
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Too many times people change cams without advance/retard changes to the existing profile. These changes can help you make an informed decision as to what changes if any are required to the existing cam. |
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