HP manifolds vs 1 7/8 headers opinions dyno results

[sneezi]

Hi Guys
 I am curious with my engine combo if i was to swap out
my HP exhaust manifolds for 1 7/8 headers what sort of gains to expect!! is it worth

440 stock stroke
6 pk rods
SRP forged pistons
10.4:1 comp
source alloy heads
1.6 rockers
comp cam flat tappet hyd 224/230@50  508/511 lift
pro max 6 pack top end
firecore dizzy with rev n nator box msd coil
23 degrees initial timing and 32 total, this is what the engine liked, no difference at 34 or 36
HP manifolds

727 stage 2 with stock converter, maybe thinking of fitting a 2400 stall
8 3/4 with 3.23 gears

Just been chassis dynoed 350.5hp at the wheels, not sure what this is at the engine.
It feels strong on the street, just curious if power is being robbed by the HP manifolds.

I tried uploading a picture of the dyno result without success (computers are not my thing)

[Kern Dog]

Even totally stock 440s will gain 20 HP from a pair of 1 7/8" headers as compared to any iron exhaust manifold. The more cam and compression, the bigger the gains by switching to headers. If you are content to live withouth that 20-30 HP, manifolds are easier to live with.

[myk]

20 to 30 HP? That's a lot for even the most insensitive butt- dyno to ignore...

[c00nhunterjoe]

That combo- 10-15hp and 30-35 ft lbs is my opinion depending on what the rest of the exhaust is.

[1974dodgecharger]

What everyone saids....

[firefighter3931]

What is the rest of the exhaust system ? 

On a build like yours a set of 1 7/8 TTI's along with a 2.5in X-pipe mandrel bent exhaust and a free flowing muffler like the Dynomax Ultraflow could be a huge gain....depending what's currently on the car. 

Based on your rear wheel HP numbers you're making 435-440HP @ the crank using 20% as the parasitic drivetrain loss.



Ron

[sneezi]

Thanks for the replies so far.
Exhaust is TTI 3 inch H pipe with the
Mufflers they supply.
I know it's a bit of over kill but it is
possible I may step up the combo
in a couple of years

[firefighter3931]

With the 3in exhaust a 1 7/8in primary tube header is the right choice for that build. That system will be good for 600hp so if you decide to upgrade in the future you'll be good to go 

From my experience dyno tuning these builds....35* total is the sweet spot using closed chamber aluminum heads 


Ron

[sneezi]

Thanks for the info Ron.....really appreciate it.
Now to decide if its worth the effort trying to get
the headers in or leave it for when i step it up in the future.
cheers

[firefighter3931]

Yep....that is the $800 question  TTI's ain't cheap but definitely worth it 

That combo should pick up a solid 25-30hp with the header upgrade 

With some head porting and a good solid cam you could be over 500hp with the header upgrade. 


Ron

[firefighter3931]

Here's a good read on a build that is very similar to yours ; Bill's engine has a very similar cam, same basic shortblock & compression with a 6-pack setup like yours. He has the TTI headers and a set of Edelbrock RPM heads that typically flow 25-30cfm better than a Stealth. With a bit of porting and the 1 7/8 header your would be pretty much the same as Bill's 

http://www.dodgecharger.com/forum/index.php/topic,52477.0.html



Ron

[sneezi]

Thanks for the link Ron.......great read.
Not sure what his eddie heads flow but my stealths flowed 280cfm@500 
Do you know if bill has taken it to the track for a timeslip, just curious what times it would do.
thanks again Ron