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Max cubic inch out of a 401 |
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Hurst390
AMC Addicted Joined: Apr/20/2008 Location: secret Status: Offline Points: 5752 |
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SC/Hurst Rambler
11.62 120 100% Street Legal |
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Ken_Parkman
AMC Addicted Joined: Jun/04/2009 Location: Ontario Status: Offline Points: 1815 |
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I have a min csa of about 3.65 sq in for the Indy CNC 300, and with the head high velocity limit (Race Engine) I get 8493 rpm for 4.375/4.150 B/S. That is pretty aggressive, and maybe a touch too aggressive for an Indy head. What it means is 8000 rpm is probably pretty good, and for sure the head is not too big. More rpm or inches is pushing it.
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DragRacingSpirit
AMC Addicted Joined: May/27/2009 Location: Mo Status: Offline Points: 903 |
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ok....thank you for your input on this issue. I understand what you are saying. There 300cc head is just not big enough to spin a 4.15x4.375 to more than 8000 rpm. So that comes down to the issue what is the best approach......spin 499 inches to 8k or use less stroke for smaller cubes and spin higher. But will that really improve the maximum horsepower potential? To bad that they don't offer a 325cc and 345cc heads like they do for their BB Mopar 440-1 head. Is there any improvement that can be done to their 300 cc head to enlarge the ports for for more port volume. To stay with a wedge design head we need a newer updated copy of a brewer head or a hair dryer/blower. I really want to see what I can get it to run n/a.
Edited by DragRacingSpirit - Nov/30/2021 at 1:12pm |
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Best 1/4 mile 8.99, 1/8 mile 5.71, 60 foot 1.27, no power adders
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Trader
AMC Addicted Joined: May/15/2018 Location: Ontario Status: Offline Points: 6761 |
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Ken_Parkman
AMC Addicted Joined: Jun/04/2009 Location: Ontario Status: Offline Points: 1815 |
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I think the Indy head is really quite good for what it is, meaning a true wedge with sorta stock configuration. The efficiency or flow/sq in is really quite good, again for a wedge. I've never had a chance to really study the Brewer (would love to) so I can't comment much, but there cannot be much in it over an Indy. You're still stuck with the inherent wedge/valve size limitation with the bore. I've had a bit of involvement with the B1 Mopar which may be closer to the Brewer, and it was a bit better efficiency and more CSA.
I don't think there is much left in the Indy - there is not much material left and it's pretty good as is. With a free hand you can get a little higher port and better angle than the 300, but it's a LOT of work for not much gain. And you probably will be welding up the leaks. If you really want an improvement you gotta go to canted. But that's a whole new game.
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Ken_Parkman
AMC Addicted Joined: Jun/04/2009 Location: Ontario Status: Offline Points: 1815 |
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BTW I would have to get those Brewers on my machine to believe that flow number. It's a little hard to stomach in efficiency. I said the exact same thing on the B1 and some other high end wedge stuff including some of the latest and greatest LS stuff. When the flow sheet shows above 100% efficiency it's pretty hard to stomach, and never once has the head matched one of those magical flow sheets.
But not hard to believe that the head is a really topnotch piece. Just everyone wants the big flow number, and some machines do that.
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Trader
AMC Addicted Joined: May/15/2018 Location: Ontario Status: Offline Points: 6761 |
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But Ken, with exchange they are only $10,225 for the pair! There also aluminum so shipping would be a bargain.
Now the brokerage fees and taxes are the big ticket. You can pay twice the purchase price. I'll look for some in Alberta as they will be cheaper.
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DragRacingSpirit
AMC Addicted Joined: May/27/2009 Location: Mo Status: Offline Points: 903 |
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I have saw those on racing junk before. I have heard a lot of
different things about the Brewer heads from differing posts on the
internet. Those pair of heads on Racing Junk are in Missouri and not that far away from me. Edited by DragRacingSpirit - Nov/30/2021 at 4:19pm |
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Best 1/4 mile 8.99, 1/8 mile 5.71, 60 foot 1.27, no power adders
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Trader
AMC Addicted Joined: May/15/2018 Location: Ontario Status: Offline Points: 6761 |
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There is a gentleman near me that has modified BB Mopar Indy heads and intake on his 390.
He does mid 11's with his 73 AMC station wagon. This is a 4000+ lb car, custom 9" rear. Don't know who did the heads, but Ken would likely know him as he races at the same track.
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farna
Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19611 |
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Bigger HP numbers are usually reached at higher rpm, but torque starts falling off before the highest hp is hit. So a larger cube engine running under 8K rpm is still likely to build as much (or more) usable power as a higher rpm smaller engine turning 8K +. High rpm/hp numbers are mainly bragging rights, but with the right combination of trans, gearing, and chassis you can make it work on an all out drag car. Not streetable though...
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Frank Swygert
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