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Oversized valves for 225 on street
https://slantsix.org/forum/viewtopic.php?t=55877		 Page 1 of 2
Author:  blkduster [ Mon Jul 28, 2014 8:14 pm ]
Post subject:  Oversized valves for 225 on street
Hey everyone ! I'm new to this site and came her because it seems this is seemingly the only place for reliable/6 info. I've been driving this 73 Duster that I saved from the scrap heap for a while and have been really fallen in love with the slant that moves it. Although I can't resist the urge to try and "hop up" the old six .Here's my question ; Is the any good tuning advice to make it run better with just the single barrel? Or should I go with a super six intake and carb(which I have) I also have an extra head and thought that I could port it myself and install larger valves as well as mill the head ? Th local engine shop says bigger valves on the 225 are a wast of time on the street but milling the head for more compression would be a good idea with a small marine cam? I would like to have improved acceleration from stop to about 70mph and just want to know what the best and most cost effective way to do that would be? Also I don't want to do any boring stroking etc just a top end really

Thanks for reading all advise will gladly be accepted ! [/u]
Author:  SlantSteve [ Tue Jul 29, 2014 12:29 am ]
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I'd say go with the engnbldr oversize valves IF your seats are pretty worn,that way you get fresh seats with the valves not recessed in the head. If your seats are OK then bang for buck would be compression increase,porting and improved cam and standard valves. Don't get me wrong,I think oversize valves help,but there is more bang for buck elsewhere.
Just as a comparison I just fitted a head with very large intakes and bowl blending onto a stock engine. The only reason I did it was I needed the head that was on that engine for another build and just wanted to keep it running for now. Even with some pretty bad shrouding from the small bore it offered a noticeable power increase,but I bet it would be just as good if not better with a well prepped,ported,standard valve head....hope that helps
Author:  Rick Covalt [ Tue Jul 29, 2014 2:41 am ]
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The super six will definitely help and since you have it I would use that for sure.
Author:  Sam Powell [ Tue Jul 29, 2014 4:23 am ]
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Welcome aboard. Yyour car is one of my favorite old Mopars.

Dyno tests have shown that the larger valves come into play over about 2500 RPM, and do not hurt low end HP or torque much. 2500 to 4000 happens to be where your engine operates when you push the pedal to the floor at 45-50- mph and it kicks down into passing gear. Dad Truck has investigated this lately, and had both computer models and real dyno runs on his slant. The stock slant really runs out of steam over 3000rpm. With bigger valves and a 4 bbl, the HP at 4000 rpm picked up an honest 90 HP.

The Super six carb is needed to feel any benfit of the larger valves, although the Super Six will be an improvement either way. Larger valves by themselves without the bigger carb are of no real value.



Sam
Author:  sandy in BC [ Tue Jul 29, 2014 6:14 am ]
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I found my street car just plain ran better after installing larger valves. I think it might be from all the other things that were done at the same time:

Head shaved....chambers radiussed....bowl hog ....port smoothing and gasket match. All cheap....all effective.

It starts with a long term plan.....
Author:  slantzilla [ Tue Jul 29, 2014 8:35 am ]
Post subject: 
Are the Engnbldr valves still available? I tried to get a set a couple months ago and there were none to be had.

But yes, big valves are a good start.
Author:  1974duster kev [ Tue Jul 29, 2014 11:33 am ]
Post subject: 
eng builder valves all the way I have them in this motor and back up NA motor.
The first motor I built gained a bunch of power from the valves some porting and a .100 head cut/cam swap

Kev
Author:  Sam Powell [ Tue Jul 29, 2014 1:03 pm ]
Post subject: 
I bought a set a couple of months ago. Did you look on ebay? I found them there, but it was ngnbldrs listing.

Sam
Author:  SlantSteve [ Tue Jul 29, 2014 1:05 pm ]
Post subject: 
Quote:
Are the Engnbldr valves still available? I tried to get a set a couple months ago and there were none to be had.

But yes, big valves are a good start.
Give him another call... I got a set about a month ago, he gets a shipment in and they do tend to go pretty quickly from what he said. Hopefully he still has a set left ,
Author:  blkduster [ Tue Jul 29, 2014 8:19 pm ]
Post subject: 
Thanks for all the great info ! I think I'll go with the bigger valves and milling the head as well as a new cam . But, what size valves should I use ,how much to mill off the head and what cam? all of this would be with the super six intake and BBD .

I, got a good deal on the car because no one wanted it with the slant ! I really love the little motors but, hate the disappointed look when I tell people it's slant six haha. So I'm hoping to change some of the local mopar guys minds on that since they think the slant six is just something to be replaced by a v8 :evil:
Author:  Sam Powell [ Wed Jul 30, 2014 4:34 am ]
Post subject: 
There are several options, but the easiest is to use the standard OS valve size Mopar Perfomance used to sell, and Engine Builders now reproduces in stainless steel. I think they are .170 and .144, or something close to that. Some have put Ford and Chevy valves in. The Chevy valves require a different guide. If you stray away from Mopar you may end up changing the geometry of the valve train, requiring different push rods. I would stick with stock geometry there.

Check out this thread: http://www.slantsix.org/forum/viewtopic.php?t=55780

Sam
Author:  SlantSteve [ Wed Jul 30, 2014 5:12 am ]
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I think BB Mopar exhaust valves can be used in the intakes with some work. The other head I have has a cut down BBC valve by the looks of it...but it's a lot of effort,by far the easiest way is the engnbldr valves on EBay,good looking little valves. They aren't a massive increase in size over stock,but they are good value.
Author:  slantzilla [ Wed Jul 30, 2014 6:40 am ]
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When we were trying to get some a while ago, Mike J spoke with a vendor for the Engnbldr valves and was told the guy was retiring and there would be no more once the current supply was exhausted. Hopefully he has changed his mind.
Author:  wvenable [ Wed Jul 30, 2014 7:12 am ]
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Didn't Ferrea make a drop in? Just went for a quick peak at their catalog and couldn't find anything.
Author:  1930 [ Wed Jul 30, 2014 8:50 am ]
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Ebay item # 380963042149
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