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Head flow |
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jcisworthy
AMC Addicted Joined: Jul/23/2009 Location: North Carolina Status: Offline Points: 2805 |
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Posted: Sep/04/2020 at 4:58pm |
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Very nice!
How much did they raise the intake runners on those heads?
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Specializing in dyno services, engine building, and cylinder head porting
rbjracing.com Phone Number 518-915-3203 |
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Hurst390
AMC Addicted Joined: Apr/20/2008 Location: secret Status: Offline Points: 5822 |
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I'm using them on a Kaplan block I found a few years ago. New never used from an ex AMC engineer.
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SC/Hurst Rambler
11.62 120 100% Street Legal |
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Hurst390
AMC Addicted Joined: Apr/20/2008 Location: secret Status: Offline Points: 5822 |
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I picked up a few more sets of trapezoid heads earlier this year. 2 sets are canted valve(slightly) and one set inline. I also got 1 original edelbrock spider intake with the heads and another unmachined from another gentleman. I plan on building a 426 around the inline set of heads that have 2.125 intake valve. Those heads have a custom heavily reworked torker. Nice on the inside,not so much externally.
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SC/Hurst Rambler
11.62 120 100% Street Legal |
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jcisworthy
AMC Addicted Joined: Jul/23/2009 Location: North Carolina Status: Offline Points: 2805 |
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Yes.... Dean Turk is the man... My family has worked with Dean since the 60's and all the heads on every Race car or Race truck we have built in the past to current have been sent to Dean... My heads for my 74 Gremlin 401 X-R are on there way to Deans as we speak... Amazing Work. Porting cylinder heads boils down to shapes, sizing and valve job. Nobody has the market cornered because of that, some just do it better than others
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Specializing in dyno services, engine building, and cylinder head porting
rbjracing.com Phone Number 518-915-3203 |
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PHAT69AMX
AMC Addicted Joined: Jul/07/2007 Location: West Virginia Status: Offline Points: 5926 |
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"Woke Up" this AWESOME old informative and revealing thread!
Ken Parkman, if I may ask... Have been trying to find your much appreciated write up text from the various CARBURETOR FLOW TEST on Fran's old forum. It is a great loss for the AMC Community that that forum is now gone. I successfully found Page 1 of that old thread using the Wayback Machine and saved your posted info from page 1... but... Page 2 with 4 more post and some more of the info from your work is NOT saved on the Wayback Machine that I can find... May I ask, might you happen to have your Oct 2008 CARB FLOW TEST text saved? Any chance it can be re-posted here or elsewhere? Thank You for all your work, shared knowledge, and valuable time.
-------- Here is what Ken Parkman CARB FLOW TEST Text from the other now gone Forum I was able to get from the Wayback Machine and save: Ken_Parkman Carb flow test 02/09/08 at 22:39:45 For various reasons there seems to be a lot of carburetors around here right now, so I decided to put them all on the flow bench for comparison. My flowbench cannot effectively measure a carb cause to do it right you need to have a bench that will suck the roof off the shop and has a direct power supply from the generating station. But what I can do is run the bench wide open and then put on different carbs and measure the pressure drop, and then I can compare one to another. I could check an individual barrel, but that takes fixtures I don't have and can't be bothered making. As you know there is way more to carbs than flow - a point that has really been hammered home to me with some dyno and track testing. Also as you know factory ratings are pretty much meaningless cause they are marketing more than anything. So this is an effort to see how much some manufacturers are exaggerating. Do not use this data to say one will make more or less power; it's only for interest. So here is the list of different carbs and their ranking flow wise, smallest to largest: Rank/Carb/part number/rating/comments 1 Edelbrock 1405 600 2 Holley 1850 600 Significantly more flow than Edelbrock 600 3 Q-jet ? ? Secondary air flap has a stop to limit opening 4 Holley 4777-2 650 5 Edelbrock 1407 750 Slightly more than 650 Holley 6 Edelbrock 1813 800 Big improvement over 750 Edelbrock 7 Q-jet ? ? Secondary air flap opened noticeably more than above Q-jet 8 Holley 4780 800 Same dimensionally as a 750, but this carb had a slight TB mismatch. 9 Holley 3310 780 Factory GM original 3310, down leg booster 10 Holley 3310-2 750 Strait booster than above, flows a little better but close 11 Pro-Systems XC ? Built for a mild 327 Chev, noticeably more flow than above Holleys 12 Holley 4781 850 No choke plate 13 Holley 80514 1000 Annular booster carb, very small flow difference from 850 14 Pro-Systems XE ? Down leg booster, very significantly more flow than 1000 Holley A couple of comments: The Edelbrocks flow significantly less than the same rated Holley Holley plays games with flow ratings. Yes a 750 Holley flows more than a Holley 800. I've heard it before, but this seems to confirm a 850 Holley is a lot bigger than a 950. Dimensionally the 850 is bigger. The 850 with no choke and a Stubstack was essentially identical to the annular booster 1000. Stubstacks noticeably improve the flow. A fancy CNC milled 2" spacer slightly improves the flow. The Q-jets were flowed with an adapter that slightly restricted the flow, but calibrating with a Holley says the restriction was not much. I'm going to try to get a few more carbs to add to this list, including a factory AFB and MotorCraft. ------------------------- Ken_Parkman Re: Carb flow test Reply #6 - 02/10/08 at 17:10:59 Trying to find some stock AMC stuff, just don't have any here! I hope to score a stock AFB and a 4300 to test, I'll post if it happens. What Reagam said is important. A high flow carb is no good if it can't properly atomize fuel at a low delta pressure. Only take this data as an interesting comparison. Of course a really good carb is both high flow and can properly control the mixture at a wide rpm and load range. A simple flow test cannot tell this. -------------- Ken_Parkman Re: Carb flow test Reply #8 - 02/16/08 at 18:22:16 Those were 2 different Stubstacks, both K & N. One is very old (been through a carb fire) and has been modified to better fit the 850, which seems to have a different height air horn then the Stubstack was designed for. The other is an almost new one made from a different plastic and fit the 750 very well. Both noticeably improved flow, but clearly the bigger 850 really liked it, the flow was well up. The spacer is a really trick CNC milled 4 hole translating to an open with a nicely flared 'bullet' in the center. But now that I am carefully looking I find it has slightly small bores on the 4 hole part. I'm gonna fix that and try again. Just scored a couple of Demons, a good prepped dyno 750 Holley, and a stock AFB. Hope to have a MotorCraft and a few more Holleys tomorrow. Will post info ------------- Ken_Parkman Re: Carb flow test Reply #14 - 04/28/08 at 02:32:16 I FINALLY managed to score some stock AMC carbs and get all the data together. I've had 29 carbs across the flow bench and it is an interesting exercise. I've learned carb flow numbers are a game. Do not assume a carb is bigger because it it rated higher. The highest flow 750 carb was 150 cfm better the lowest flow 750. A surprise is the stock MotorCraft 4300. I scored a OWA4-S, and it's surprisingly good flow wise. It looks crappy, but flows a tiny bit better (not enough to give a number) than a Demon 625 or an Edelbrock 600, both of which are pretty much the same. A Holly 600 is about 40 cfm better than the BG and the Ed. The stock AMC AFB (tested # 4664) is about 40 cfm less than the same BG and Ed Carbs. The Ed 600 is an AFB and is basically the same carb as the stock AFB. It has the same bore's and venturi's, but the Ed has 1/2 throttle shafts and a little aerodynamic fairing to account for the 40 more cfm. The 4350 MotorCraft is the same as the stock AFB. I scaled the carbs on a 0-100 scale, and here are the small carbs Edelbrock 750 (1407) - 71 Holley 700 (4778) - 71 Holley 650 (4777) - 69 Rochester Q-jet (xxxx) - 67 (small one) Holley 600 (1850) - 65 MotorCraft 4300 (xxxx) - 61 (OWA4-S) Barry Grant 625 (xxxx) - 61 (Road Demon) Edelbrock 600 (1405) - 61 Carter AFB (4664) - 57 MotorCraft (4350) - 57 --------------- (4) MORE POSTS ON PAGE 2 -> BUT NOT ON WAYBACK MACHINE ! ------------------- Edited by PHAT69AMX - Feb/20/2019 at 5:00pm |
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Randall Racing
AMC Apprentice Joined: Jul/03/2012 Location: Mesa,Az Status: Offline Points: 228 |
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Yes.... Dean Turk is the man... My family has worked with Dean since the 60's and all the heads on every Race car or Race truck we have built in the past to current have been sent to Dean... My heads for my 74 Gremlin 401 X-R are on there way to Deans as we speak... Amazing Work. |
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Cory Randall
74 Gremlin 401 X-R |
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SuperStockAMX
AMC Apprentice Joined: Dec/29/2009 Location: Anthem, Arizona Status: Offline Points: 237 |
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The cylinder heads that flowed the "impossible" 270 CFM had the heat riser ports filled / welded per allowable rules and were confirmed by NHRA tech. In fact the car was teched above and beyond normal tech. I would bet money that Class Guy could obtain the same results.
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SKeown
AMC Addicted Joined: Jul/30/2009 Location: Texas Status: Offline Points: 3085 |
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Drag racing a class car is like endurance sports. Even though steroids are banned, I doubt a single gold medal has been won by anyone without them in the last 40 years. I've run 13 marathons and raced bicycles throught the US, Canada and Europe, I can assure you that's the way it is.
If trick valved and seats could provide a 45 CFM gain, more would be doing it.
SKeown
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Ken_Parkman
AMC Addicted Joined: Jun/04/2009 Location: Ontario Status: Offline Points: 1814 |
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As well the throat area of the bowl area is the unfilled part on the trapezoid mold. We had a leak in the casting during the pour and there wasn't time to do another. There actually was not enough time to do that one, we had to take it out before the material was set. The stuff I use really needs 24 hours to properly set.
So the mold is decieving, there is more ss than it looks. The trapezoid is a race piece with way more capability than stock. I really like the csa through the middle.
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Hurst390
AMC Addicted Joined: Apr/20/2008 Location: secret Status: Offline Points: 5822 |
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As for Jeffs ss heads...I beleive that his MACH man did get 303cfm...from what i hear from highly reliable sources is that he is a genius....as far as 270 out of his stock head i believe that also..but the problem is that most likely porting was done( I sure can't prove it..lol) with methods to make it look like no porting was done...those are tricks as old as class racing itself...thats why Jeff has to spend the kind of $$$$ on the heads he runs...cheating...you can call it that...but when everyone does it in some form and you want to be competitive then eventually your going to have to read between the lines...thats class racing of any kind....
Hammer on me all you want but that is my opinion...like it/him or not...
as for ss racing...there will soon be the 1st SS/B AMX in the 8's..The HP is there to do it..he has to get it to the track and get the car worked out....this is an nhra SS legal engine....
Edited by Hurst390 - May/13/2010 at 7:59am |
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SC/Hurst Rambler
11.62 120 100% Street Legal |
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