GAINS FROM RAISED PORTING INTAKE AND ALUMINUM HEADS

[TIMINATOR]

I have a set of aluminum heads that I will port and wondering if raising the top and widening the port to the big gasket size will gain much.
Heads now only flow around 280 and I own two sets, a Chinese set and performer RPMs too. There is enough meat in two of the intakes I have to do this. Just wonder if anyone has done this.
TIMINATOR

 

[Challenger RTA]

I pay close attention to what you say. I think you are one of the few here in a class of you own. Very knowledgeable. You know what you are doing. Now I wonder if this is a test? Maybe your just seeking a first hand experience. No offence meant here.

This is why our mopars where built.

 

[TIMINATOR]

Not a test.
Ported stock 440 heads gain about 28-34 cfm with this max wedge porting. You don't even need to widen them to get some gain.
But stock heads have a big hook in them that aftermarket heads dont. But since I have performer rpm and raised runner speedmaster heads I was wondering if anyone has flow tested with raising the inlets. If no one has got this info I guess it's back on my flowbench and map the port before doing any work.
If no definitive answers I guess I will get on it in my spare time. Which I don't have much....
TIMINATOR
P.S. ya gotta raise the intake manifold too. Some can be raised more than others. "In the day" I raised the intake first a safe amount, then raised the heads the same amount.

 

[Challenger RTA]

Knowing enough to be stupid. I was thinking the maybe the intake could be machined to lower it to match the heads. Same as when the block is decked the intake side needs to be machined to some extent. Just wasn't sure how they were matching up originally. It's all the opposite of what I was thinking. Thanks

 

[Xcudame]

Maybe I'm lazy, but if I wanted Max Wedge flow, I'd just buy a pair of Indy or 270 TrickFlow heads and their intake and call it a day. Seems like a lot of work for something that will probably flow more than the "stock" head, but less than a "max wedge" type head. You could sale the two sets you have to help offset the cost of Indy or 270 Trick flow Heads.

 

[TIMINATOR]

I have 3 motors and 3 sets of heads. And a flow bench. And a dedicated porting room.
Factory iron heads have a big hump in the floor and raising the top of the port gives a straighter shot to the bowl with a good flow gain
Edelbock and 440 source (I have a pair of each) minimize the hump and the speedmaster (other set) raises the floor around 5/8" and extends the port higher so to minimize the hump completely.
Time to see what they all flow.
I will apparently use the lesser heads on the 2 498s and speedmaster raised ones on the 512.
I need to either get 2 A bodies or a shortbed truck. The 72 Challenger gets the 512.
All of the heads are stock as of now. I will post some stock numbers. 440 source, e brock and speedmaster advertise almost identical numbers. I can't see that the raised ports only flow the same as stock location ports. The bench dont lie. We will see and I will post.
TIMINATOR

 

[Xcudame]

Oh, this should be interesting! My understanding of the 440 Stealth head is they were just trying to recreate the stock "906"/"915" head in aluminum. If I had to guess, I'd say raising the top of the port would be good for 15-20% flow gain at the higher lifts. Will be interesting to see your results!

Which Edelbrock heads? E-Street?

 

[TIMINATOR]

Performer RPM.
Those and the 440 source came In a package deal. The Speedmasters look much better by eye. I don't think the 440 source and perf rpm will flow much better than pocket ported 906s. We will see...
TIMINATOR

 

[Chryco Psycho]

I have experimented with porting a LOT over the years but I don't have a flow bench , just time slips !
the motors I build Always run faster than they should ...
Anyway you will see some gain raising the ports for sure ... my $.02
Where I have made serious gains tho & messed with people on flow benches is concentrating on swirl , using a venturi to increase air speed & shaping intake & exhaust guides into a wing shape with a long side & short side like a wing then twisting the flow so it hit the back of the valve around 50* resulting in no loss of flow @ .100 lift & no stall in the port to .750 lift .
I have also seriously raised the transition from the carb base on the intake into the ports making a heart shape , wider with a smooth blend at the top & narrower at the bottom .

 

[TIMINATOR]

O typically run a 1" or 2" spacer from 4 hole to open and make the transition radius into the port start up inside the spacer. The 4 hole to open cnc spacers work well on most everything that I have tried. A big mistake many make is running too large of an intake. The air is accelerated in the carb, then slows in the intake and has to reaccelerate in the port. Jetboat guys usually make that mistake, as well as the dragracers. It's that kind of stuff that happens in the real world that the flowbench doesn't show. My 572" BBC jetboat motor with CNC'd Brodies and 274 @ .050 roller with an 1150 Dominator preferred a 4150 dart intake with a 4500 to 4150 adaptor over a Dominator flanged intake.
That was +58 HP at 5800 rpm where the pump held it to. You can't believe how many folks called me cheap and told me how much better it would run with the "proper" intake.
I never argued?, just agreed with everyone that I really was cheap and stupid!
The area of the 4 throttle bores together was slightly smaller than the throat of the intake and adaptor.... Sometimes your eyes lie, that's where experience, and a flowbench are helpful.
TIMINATOR

 

[TIMINATOR]

Looking at a set of Speedmaster 200cc as cast SBChebbie heads, the intake port at the flange are almost the same size as the Speedmaster 440 mopar ports! According to their published specs, they both flow about the same! But the chebbies have a 2.02 valve and the mopars a 2.200 valve. That leads me to believe the restriction is the initial 2" or so of the mopars port in from the flange.
The 440 source heads port is quite similar too, but the divider is thicker on both aftermarket brands mopar heads restricting flow there. I will start my mods in the first few inches of port, then raise the port to the max wedge size, as my past port work on iron factory heads shows that raising the stock port increases the flow even with no other port mods. I first raise the intake manifold port as much as practical, then match the head and gaskets or use max wedge gaskets. I also weld the intake manifold port tops allowing more grinding on aftermarket manifolds, even though they have more meat on top than factory intakes. The factory heads can have the port tops raised as there is plenty of meat up there.
Most aftermarket manifolds have plenty of meat on the ports top to get noticeable gains. Why everyone's aluminum heads don't have max wedge intake port sizes, I have no clue! It just doesn't make any sense!
When time permits, I will get on the flowbench and post more, but now you all have something to consider!
TIMINATOR