Mopar street heads vs. Porting stock heads?

[LTHL VPR]

Can anyone tell me what the stock heads flow?
How much of an improvement in flow and hp do the Mopar street heads perform?
How about compares to porting/polishing, etc.. the stock heads?
The real question here is truly which will yield more hp:
Ported stock heads, or Mopar replacement heads?
Thx!

[Fred(DrivingSchool)Kinder]

The starting point is stock heads. Not sure the source of Mopar CNC heads but I think they use CDI for a source some product. Porting and polishing can be done by many sources with varying results. I am sure you know that. Remember the engine builder for the Vipers that won Le Mans, FIA series and ALMS series? It was CDI.

[Dan Vargus]

Don't bother with the big heads if you don't modify the whole engine. The Stock heads can flow upwards of 270 CFM depending on who does the work. The stock intake will only flow 225 CFM if modified. So why big heads, that flow more then the modified intake? The main advantage for the Mopar Hi Performance heads is cooling. They hold more water therefore are much better for track time. The Viper engine is a mid range tork engine, if you are going to increase performance try thinking in the the terms of more air and fuel velosity rather then volume. The same is also true for the exhaust system.

My 3 cents worth, Dan Vargus/PartsRack

[Bob Woodhouse]

Dan, I almost always agree with you but an exception exists in this case, the manifold and throttle bodies are good for allowing another 100 hp before they become the bottleneck. Heads, especially when combined with headers can do some good. Heads alone such as the ones in the MoPar catalog and no mods will bring you 40 hp. Here below is the info from the Mopar catalog, also available from our site.www.woodhouse.com/viper

"A356-T6 aluminum alloy with high flow ports and a fully machined combustion chamber. Out of the box, it flows more CFM than any production head. Direct replacement for production cylinder heads.; 230cc Intake and 73 cc exhaust ports.; 74cc combustion cahmber volume (same as production).; Designed for production valve train or Mopar roller rocker arm assy.; 18 degree inline valve angle.; Tool steel valve seats with iron alloy valve guides"



<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Dan Vargus/PartsRack:
Don't bother with the big heads if you don't modify the whole engine. The Stock heads can flow upwards of 270 CFM depending on who does the work. The stock intake will only flow 225 CFM if modified. So why big heads, that flow more then the modified intake? The main advantage for the Mopar Hi Performance heads is cooling. They hold more water therefore are much better for track time. The Viper engine is a mid range tork engine, if you are going to increase performance try thinking in the the terms of more air and fuel velosity rather then volume. The same is also true for the exhaust system.

My 3 cents worth, Dan Vargus/PartsRack

<HR></BLOCKQUOTE>

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[Supercharged Vipermad]

For those interested, I'm going to test this question in about 3 weeks. By that point, my car will have:

K&Ns
Smooth tubes
Belanger Headers & Catback
High-flow 3" cats

In late March, I'm throwing the following into the mix:
Hennessey Heads / Valves / Valvetrain
Hennessey-sourced roller rockers and 1.7 rocker arms
MOPAR ECU
Al flywheel
Pulley kit

As always, I'll have before & after dyno results. Since the effect of the other components I'm adding is well known (10-12 from rockers, 5 from flywheel) I'll have an excellent idea of how much reworked heads can buy on an otherwise stock engine.

Ben "the data collector" Treynor

[BurnR8]

has anyone done headwork that they want to speak about? I have thrown it around...but I do not have too many miles on my car and do not want to step unless there is a major difference....induction and exhaust are already taken care of....just need to improve combustion.....BTW- Hey Ben...nice move on the stock today in a crappy market....thanks ;-)

[HouseofSpeed]

You guys know that BuddyBar does the castings for all of the Viper heads right??? Including the GTSR...you might give them a shout if you were curious about the porting integrity (ie available meat) differences between the heads. Just an FYI.