Real World Power gains from head swap..

OK
My father-In-Law has been restoring a very nice pro street Duster. He is a old School Chevy guy, that I converted to Mopar Power since I married his Daughter. LOL.
Anyways Here is the current setup
Chassis is a 72 Plymouth Duster all steel except glass deck lid. Car has been tubed for 14x32 slicks but he currently runs old School M/T Sportsman Pro tires Like 19x32 IIRC. It has 8 3/4 4.10 sure grip with Moesr axles. 10 Point roll cage, race seats etc.
The engine is a stock 71 440 block bored .030 and uses a Keith Black Hyper pistons, IIRc like a 237 part number which is suppose to be about 10:1 with his stock Iron heads. Im thinking they are 452's which have been home ported, with large valves. It has Isky adjustable rockers, and a Comp Solid flat tappet with dur in the 270's at 50 and around .570ish lift. Converter is a GER (yea I know) 4500, which has been proven to be a decent piece actually. It has a M1 intake 4500 series and uses a adapter for a 850 DP holley carb. 6AL MSD ignition, I rewired the car and installed a ARC Switch panel, put all electronics on relays etc.
Before He picked the car up off my buddy, it had a 4.88 gear (maybe 4.56) and a 8896 dominator. All else the same, it ran 7.40-7.30 range in the 8th mile. Not to bad IMO.
Anyways
He has spent some money cosmetic wise on the car, having it painted, all new wheels, new interior, recovered seats, new carpet, head liner, door panels etc. New headers the list goes on and on. It really is a nice looking car.
I have been on his case for a few months now about upgrading the cylinder heads.
I have run about every head out there in between stock, and CNC ported Indy's. The Edelbrocks would enable him to reuse about everything. Rocker gear, intake headers, which are tight fitting new Ceramic Coated Headman Hustlers he dropped about $900 for. So in any case he would shat a brick if we got him some heads and he couldn't reuse these. I will look closer at fittement issue's etc.
So It looks like the Indy EZ's would be first choice. Then maybe the Victors if, and only if we can make the headers work without major mods.
I know He wont spring for a set of CNC ported heads.
So If we picked up a set of Indy EZ's, maybe picked up a Intake, like the Victor or Indy and opened the as cast heads up to max wedge ports, and If I done some bowl work/ blending. I have done my fair share of port work, so i dont consider my self a Novice.
Im thinking the engine is making in the neighborhood of 450-475 hp right now. I would be totally shocked given the increase in compression, and head flow if this thing didnt make over or right at 600hp. Is this a out of line estimate?
This should push the Duster well into the 6's no sweat, and be a fairly reliable combo that doesn't need to spin to the moon, and require race by race maintenance.
Here is what I want to do.
I want to get the car lined out have all the parts on hand to do the swap at the Mopar Southern Classics this October at Mountain Park Motorplex.

My 906 headed solid cammed 470 made 615 hp and 598 tq on Pettis`s engine dyno and went 10.48 @ 3200 lbs w/my dumb a$$ driving and tuning it. I now run home ported rpm`s and a solid roller Isky cam and went 9.98 so not sure what just a head swap would do but I would think the max wedge port would help a BUNCH. Good luck.

Okay we went 11.50 with a very mild 440 with 915 heads. Went to a stock set of Max wedge heads and went 10.93. Thats the best I can do with back to back tests.

I made the head change at the same time I put the motor in the charger so my results may be tainted as it is much lighter than my old car.

That being said, I put on OOTB eddy heads and noticed a real difference in the motor right at the start of the burn out. Rev'd quicker and harder than it ever did with the stock iron heads.

With Iron heads this motor pushed a 3400# car to mid 12's

The entire drive train and axle went into the charger but it's 2800#'s. But if you figure .1 for every 100 #'s that still should have only put it in the high 11's had I left the iron heads on.

As far as fittment issues go, I seem to recall hearing stories of headmans not wanting to fit the eddys angled plug location.

I don't want to start a but for the he's spent on the headers and wanting to reuse those you might want to consider the stealth heads. Those heads plus the flow work might still be the same price as the OOTB eddies

Quote:

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I made the head change at the same time I put the motor in the charger so my results may be tainted as it is much lighter than my old car.

That being said, I put on OOTB eddy heads and noticed a real difference in the motor right at the start of the burn out. Rev'd quicker and harder than it ever did with the stock iron heads.

With Iron heads this motor pushed a 3400# car to mid 12's

The entire drive train and axle went into the charger but it's 2800#'s. But if you figure .1 for every 100 #'s that still should have only put it in the high 11's had I left the iron heads on.

As far as fittment issues go, I seem to recall hearing stories of headmans not wanting to fit the eddys angled plug location.

I don't want to start a but for the he's spent on the headers and wanting to reuse those you might want to consider the stealth heads. Those heads plus the flow work might still be the same price as the OOTB eddies

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Thanks Guys
The Indy EZ's have stock exhaust port location, so I assume they would fit like a glove.
IMO
The Indy EZ's are what I am going to talk to him about. The leave room to grow down the road too. Right now my plan is to just do a head swap, with some nice bowl work, and gasket matching.
Id be surprised it this same engine couldnt muster 575-600 hp.