X heads that flow 250 on 416

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swinger340

swinger340

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I have been looking at my 416 short block for some time now and life keeps throwing BS @ me so I an unable to buy the heads I want at this time. I do in Fact already own some Fresh X heads that with some port work that flow 250/172 @ .550 Im very tempted to just say screw it and use them w/ A comp XS282S cam .520/.540 244/252 @.050 in which I already own as well. Any thoughts as to what my loss in power will be. The X heads are 68 cc. so that will also drop my wanted compression ratio from 10:1 down to 9.7:1 My original plans were some alluminum heads that flow 275-280 and a bigger voodoo 30200741 .546/.566 243/251 cam. I want to start driving this thing already, but will not be reaching my 500/500 hp/tq goals.
 
Save up for what you want. Will save time and $ in the longer run.
 
i run that cam in my 360 with some home ported J heads. i ran 12.22 with a 1.66 60 foot with 3.91's and the jetting was way off. Those X flow descent, if anything for now i would sell your cam and go with something in the 250 @.050 on the intake side. with every thing else up to par i bet you would run very low 11's .
 
They'll work fine and I'd estimate around 430hp and 490ish torque. I don't think you'd be disappointed and you can always upgrade later.
 
Rocket said:
Save up for what you want. Will save time and $ in the longer run.
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Very true. Been selling few items to try and save for my heads. Running out of stuff that I "WANT" to sell. Wonder what the (fresh) X heads would sell for? Were originally done for my date correct 340. May try selling a wheeler or some guns locally. I got to many expensive hobbies. LOL!!!
 
Selling firearms, depending on what they are, can certainly yield some decent money, but that's one thing I personally would have a hard time doing...stupid bills.
 
Hey, they're bought and paid for. Can always swap to new heads later... life is too short to put stuff off sometimes, work with what you got for now, improve if possible later. What would it cost - the heads and a head gasket set...
 
250 cfm should be able to support 500hp, also thats not much of a drop in CR. i would bet if you use some of the good HP calculators and punch in some different cams with the heads you have you will see near or at 500hp.
 
airgrabber said:
Hey, they're bought and paid for. Can always swap to new heads later... life is too short to put stuff off sometimes, work with what you got for now, improve if possible later. What would it cost - the heads and a head gasket set...
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moper said:
They'll work fine and I'd estimate around 430hp and 490ish torque. I don't think you'd be disappointed and you can always upgrade later.
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What they said! Put it tighter and enjoy it for what it is now and upgrade later. I purchase my parts and simply store them for later. When I get everything I want the way I want it, I upgrade it all in one shot. BAM! Done.

It's worth the wait. And when you feel the power differance, it will be great.
 
I recall the 416 Mike built w close to 500/500 on iron heads and a comp xe274s cam. I imagine he worked some serious magic on them heads. My x heads are limited to .550 lift did not originally go to extreme because they were going to be going on a stock appearing 340. My exhaust side is lacking a little flow, but not real bad for heads that started at 235/150
 
The first 408 I built was a J headed motor. It had a mopar cast crank int. balanced with custom diamond flat tops 12:1 and eagle rods. Had a Solid cam .587/.603 lift (.259/[email protected]). Had a strip dominator manifold nothing trick. 73' duster with super stock springs that weighed 3250 with me in it. Messed up carb with 3.91's with traction issues it went 11.21@121. Trans was a 904 and had a 10" 4200 stall by dynamic. Never made a good pass in that car before hurricane Katrina. Long story short your X headed street motor will be fine. My heads where ported by Hensley and my local machine shop did the valve job and installed ferrera 6000 series stainless valves. There where port matched and had a little short turn work, far from a full port.
 
I would just run the Voodoo Cam. You said the X heads have the highest flow rating at .550 and the Comp cam is only .520 and the Voodoo is .546 which sounds more suitable to me for peak performance. As far as the compression ratio go's at least you'll once again get a peak performance off pump gas. Anything 10-1 or more requires higher than premium pump gas for peak performance. Just food for thought!
 
Junk the whole thing and send it to me.
 
moper said:
They'll work fine and I'd estimate around 430hp and 490ish torque. I don't think you'd be disappointed and you can always upgrade later.
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I agree. I know a guy running a mildly worked set of X heads on a 408 in a 69 Dart and with just 3.23 gears and a 3k stall runs high 11's. Put it together and have fun while your saving up for some really good heads. Doing a top end swap isn't that much work

My guess is you can run the Voodoo cam even though the exhaust lift is rated at .566 and you say the X heads will only support .550 lift. Reason being is the lift loss due to the complex pushrod to lifter angle is anywhere from .025-.040". That puts the Voodoo cam at a max valve lift of no more than .540".
 
I am starting to wonder anymore .... is all this RHS .... Edelbrock cyl heads really needed for a " SREET" car ... IF mike can get near 500 tq/hp out of that cast iron headed motor ...
Just wondering if it is worth investing money in X or J heads ... to equeal RHS/Eddies???
and what would be the final price when comparing COMPLETED Stock iron heads ( capable of 500 hp/tq) to Aftermarket replacements ???
Why not go this route to save money and build a stroker bottom end ...
 
I'm going to run some worked over iron rams(2.02,mild port work) on a high comp, forged 408. They flow 270ish at .600. Shooting for high 10s n/a and then toss a "little"(aka alot) spray at it.
 
rrvolare said:
I am starting to wonder anymore .... is all this RHS .... Edelbrock cyl heads really needed for a " SREET" car ... IF mike can get near 500 tq/hp out of that cast iron headed motor ...
Just wondering if it is worth investing money in X or J heads ... to equeal RHS/Eddies???
and what would be the final price when comparing COMPLETED Stock iron heads ( capable of 500 hp/tq) to Aftermarket replacements ???
Why not go this route to save money and build a stroker bottom end ...
Click to expand...

My biggest issue is the open chambers. You can use modern techniques with a closed chamber head that benefit in mileage, power, and longevity. It's not all about airflow or peak flow rates. It's about the package.
 
moper said:
They'll work fine and I'd estimate around 430hp and 490ish torque. I don't think you'd be disappointed and you can always upgrade later.
Click to expand...
I totally agree with Moper!!!

I also have X heads on my stroker with a thumper cam and am getting 320hp to the ground. I too would like better heads and a bigger cam, but it runs nice, I would put it together and run it you will be happy, and can upgrade later. JMO
 
rrvolare said:
I am starting to wonder anymore .... is all this RHS .... Edelbrock cyl heads really needed for a " SREET" car ... IF mike can get near 500 tq/hp out of that cast iron headed motor ...
Just wondering if it is worth investing money in X or J heads ... to equeal RHS/Eddies???
and what would be the final price when comparing COMPLETED Stock iron heads ( capable of 500 hp/tq) to Aftermarket replacements ???
Why not go this route to save money and build a stroker bottom end ...
Click to expand...

moper said:
My biggest issue is the open chambers. You can use modern techniques with a closed chamber head that benefit in mileage, power, and longevity. It's not all about airflow or peak flow rates. It's about the package.
Click to expand...

What Moper said is true. BUT too many people in my opinion forget that just because the new stuff is better in ways that doesn't mean factory heads don't still work. Many people had .509 cammed small blocks with J heads that ran quite well before comp cam, eddy headed small blocks were around.
 
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