Do these Stage VI heads need ported?

[ChallengerVert]

Still waiting on the paint shop but wanted to get the engine ready in order to put together.  The engine is still dissassembled.  My question is do you think I need to port my Stage VI heads with the combo that I have?  Or will the heads out of the box be fine with my setup?

The reason I am asking is that, if they do need ported I will have to ship the heads to the mainland, as no one here in Hawaii is good enough to port MOPAR heads, and Stage VIs are a little different and not very common.   

The engine is going into a Challenger Convertible and will be street driven to car cruises, and hopefully make some 1/4 mile trips at the track, at least one before busting the 13.99 restriction as I do not have a roll bar or cage.   Hoping to get into the mid to low 11s. 

Here is my setup:
493 Cubic inch 70 HP2 Block 4.15 stroke, 4.35 bore
Ross piston flat tops with 4 cc valve reliefs, should be about 10.25/10.50 - 1 compression with 78 CC stage VI heads (have not done measurement yet)
Stage VI heads with .030 gasket
TTI headers 1 7/8 tube 3" exhaust (have not purchased yet) afraid to go 2" tube as it might be too tight?
.590 MOPAR purple shaft Solid Cam
6 pack aluminum intake with spacers,  Carbs will be drilled, metered and jetted for cam
Aluminum 18 Spline 4 speed
Dana 60 with 4.10
Sub frame connectors
A light car for a convertible, no options, heater delete, manual steering, lightweight 4 wheel disk brakes, aluminum water pump, fiberglass hood etc...

With this setup choke at the heads or will they need ported?  I hope I can make it without out porting as shipping to and from the mainland and a good porting will probably cost over $1400.  Does not seem like much but I have spent a ton on the car already.

Here is a link with how the restoration is going so far.  Still waiting on paint for the last 5 months!!!!

http://moparshawaii.com/forum/showthread.php?t=11

[Chryco Psycho]

personally I port everything but I do the porting so it is no big deal , yuo will gain even with unported heads but more is always available as well , what would shipping cost < you could send them to me

[ChallengerVert]

Shipping will be about $100 one way to mainland.  Do you think my setup needs it? Or will the heads be choking? 

[Oldschool]

I think at least "cleaning up" the ports is always a great idea.  Performance is all about flow.  Correctly ported heads flow more than stock heads.  If CP is willing to clean em up for you, you ought to take advantage of it.  Pretty good bang for the buck really.  Just my 0.02.           .....Oldschool

[Chryco Psycho]

will the heads wrok better than productions heads without porting ? .... Yes
 I know what you are asking , & yes it will work without porting , but there definatly is a gain with porting ....your call

[ChallengerVert]

Thanks CP!!!! 

[Follicly Challenged]

You say you only want to get to mid/low 11's ?

With a 28" tall tire ? ? , on the 4.10's with a stick, "IF", you want to "USE", and balance, your power & torque for this "ELAPSED TIME" dragrace, you really don't need to spin your 493" inch deal much past the 6000 mark in all 4 gears.

It don't matter what version of the STG VI head you have, you have more than sufficient airflow for THIS criterion, "BOLT ON", untouched. Probably a more "useable" torque curve for the 6000 shift point untouched because of the higher port turbulence/Torque.

I'M NOT SAYING, that any "porting" won't increase flow, IT WILL, just that, unless you're planning on racing in only 3 gears of you're 4 spd., and planning on rev'ing higher, it isn't required. You're not gonna USE  it cause you ain't goin there.

Simple formula for your "particular" application;
Assumes flat tappet cam, 10-10.5 C.R., benzene ring(gasoline)
Take your estimated head flow at "peak lift" X .2475 = potential Horsepower that can be supported per cyl X 8 cyl.
We'll leave the rpm/inch factor 'outa this calc., trust me you're OK for the 6000 rpm.

If you can get to 6000 rpm in all 4 gears, AND be doing 6000 in 4 th at the traps, you'll be doing around the 120 mph mark ! With any kind of 60 ft time at all, you're trying for 10's ! 

NOT LIKELY this will happen, problems with tire/gearing/combo, this IS a street application, not a dedicated drag chassis.

But anyway, back to "Can your heads support the power/torque your targeting" ?

Any version STG VI has gotta flow 280 @ .600". (or more)
280 X .2475 X 8 cyl's means "outa the box" they should support 554 ? Horsepower @ the 6000 rpm mark.
That should be sufficient for your goals in a maximized application(non 3 gear race), dunno how it's gonna work on a 4 spd when you're only using part of 4 th, but should still gain 11's at "whatever" mph.

Bottom line, PORT if you're gonna "go for it", higher than than a 6000 rpm shift point at the strip, mainly the first 3 gears, and cross the traps in 4th at a lower rpm. If you're gonna shift @ 6000, and try to get wherever you can in 4th, they'll work fine the way they are.

Good Luck, hope it helps.

[Chryco Psycho]

Basically we are discussing a mild street engine here not a full raace effort so you will gain with mild porting & clean up with massively hogging the ports & killing all velocity 

[ChallengerVert]

Follicly Challenged,

Your analysis is awesome!!!  Yes I am running a 28" tall tire by 12 1/2" wide, in both a street tire and a set of slicks that size too for the strip. 

Not going above 6000 RPM will be better as well.   

I guess I could just clean them up with a mild polish and get them together.  You and CP are awesome and thanks for the great advice!!!

Joe

[Follicly Challenged]

I guess I'm not understanding, I must be confused, or, not making myself clear ?

A Mild cleanup always HELPS, but long story "cut short", I thought the question was, will the heads "choke" in THIS application, that being mild "street".

Answer is a definite NO, they WON'T CHOKE, if the definition of "choke", is relative to "can the head still deliver ".
YES, THE HEAD CAN STILL DELIVER MORE "GOOD QUALITY" FLOW, installed "box stock untouched", on a 493 @ 6000 RPM.

"ANY" stg VI port head, is nowhere near going "sonic", on a 493 @ 6000 rpm. SCFM will still be good at .600" lift, even UN-CLEANED UP.

It DOES NOT, absolutely, positively, have to be ported or cleaned up, to deliver approx 554 hp., or more ? Not sure how much HP is wanted here, or rather "where" rpm-wise, in this NON RACE deal ?

However, it WILL, do so EASIER, with a HIGHER overall curve, with HIGHER rpm peak events, when "Cleaned-up".

How much does ChallengerVert want ? where ? How high rpm ?

It's your call.

[nivvy]

Challenger Vert...I hope this helps you...I recently had a 500 stroker built....specs are as follows

440 bored 55 over (499 c.i.)
Solid Roller cam .614 / .620 lift with 1.6 roller rockers
"906 :" heads Ported and Polished
2.14*1.81 Manley valves
 dual 600 edelbrock....converting to domiator setup
power steering
mechanical water pump
March Serpentine pulleys
727 / 3000 stall and 3.91 gears

Your heads are better flow than mine... I have a roller setup and good pulleys...

I beat the fastest 5.0 in my town that runs 11.60's on nitrous....

my challenger is a full steel car minus the 6pack hood...and I alos had 2 friends with me during the race which was another 350 lbs......

How much are you really looking for....because everything I told you here is 100% true with no bs...

8 Pack

[firefighter3931]

493 Cubic inch 70 HP2 Block 4.15 stroke, 4.35 bore
Ross piston flat tops with 4 cc valve reliefs, should be about 10.25/10.50 - 1 compression with 78 CC stage VI heads (have not done measurement yet)
Stage VI heads with .030 gasket

Your static compression ratio calculations are way off. The Ross stroker pistons will sit .017 below deck assuming a blueprinted deckheight of 10.72....this puts you at 11.82:1 with a 78cc chamber and a .030 head gasket. That's way too much for pump gas if that's what you're looking to run in this car.

As for the stage 6's....they need to be worked on an engine this big. They typically flow in the 260cfm range out of the box. The ports are in the 210cc range which is "smallish" for a 493. The motor may pull good to 6k but that doesn't mean it's making more power there. The 590 is a good cam but there are better grinds out there for sure. Something on a 108-110 lsa would be better, especially with a closed exhaust system....tight lobed grinds don't like being capped up.

The "if it were mine" answer: Drop the static compression ratio into the 10.5:1 range and zero deck the block for tight quench. This will require a custom inverted dome piston to dial it all in. Use a .040 composition headgasket to create your quench zone. Less cam can still get the job done and be waaay more streetable. Most importantly, port the heads and increase the cross sectional area (and flow) to allow the big dog to breathe. The TM7 is a good choice but you don't really need a dominator to make the big power number....a 950hp 4150 style carb would suffice. A 1in open spacer would help to increase plenum volume and still clear the hood with a drop base aircleaner.

Here's a stroker build that i just went through with a member on another site. This is an easy 550hp/600tq combo that will run on pump gas and idle like a stocker with the street hemi cam. 

http://www.dodgecharger.com/forum/index.php/topic,782.0.html

Ron

[ChallengerVert]

Well, I was all prepared to put the heads on as is, now looking at sending off to get ported.  This is going to cost some bucks.