NEW DART 8.1 HEADS

[Tyler Crockett]

Getting ready to test the new Dart 8.1 496 heads. We also have this sheet metal single plane manifold that will be later cast in aluminum and also a duel plane manifold. We will run the manifolds with a 850 carb but the manifolds will also be availible with fuel injector ports. I am also going to put a Mefi 4b on and run the stock efi intake.

 

[FTMBOB]

Nice! Are those cast iron heads(kinda looks like it in the pics)? Keep us posted on results. Do you have any flow numbers?

Bob

 

[rschap1]

Good Luck
Looks like a pretty cool intake set up there

 

[Donskihp]

I've been keeping my eyes open for some 496 Alluminum heads to replace my stock merc heads when I refresh my Whippled 496. Raylar is the only one so far that I know of. Options would be nice!

 

[Tyler Crockett]

Nice! Are those cast iron heads(kinda looks like it in the pics)? Keep us posted on results. Do you have any flow numbers?

Bob

Yes Bob they are iron and they flow better than a fully ported stock head and these are right out of the box so there is plenty of room for porting. I ran this setup yesterday on a stock shortblock with just a cam change and made almost 600 HP. We are going to put the stock efi manifold on and a Mefi 4 today and run it.

 

[Tyler Crockett]

I've been keeping my eyes open for some 496 Alluminum heads to replace my stock merc heads when I refresh my Whippled 496. Raylar is the only one so far that I know of. Options would be nice!

We are going to have a camshaft package with the heads for a bolt on power gain that will be real cost effective.

 

[Ratickle]

Yes Bob they are iron and they flow better than a fully ported stock head and these are right out of the box so there is plenty of room for porting. I ran this setup yesterday on a stock shortblock with just a cam change and made almost 600 HP. We are going to put the stock efi manifold on and a Mefi 4 today and run it.

Are you able to adjust the MEFI 4 parameters to take advantage of the better flow, etc? Or does it have to be replaced with an after market brain like my Haltech's?

 

[Donskihp]

600 HP naturall aspirated, impressive, so what would we be looking at with a Whipple screw kit and CMI sport tubes? I'm a real gluttin for punishment,because it took Dustin Whipple 9 months to get my PCM to work with my motor.

 

[Tyler Crockett]

Are you able to adjust the MEFI 4 parameters to take advantage of the better flow, etc? Or does it have to be replaced with an after market brain like my Haltech's?

Rat I can program the Mefi controller. I ran it today with the stock efi manifold and mfi 4 and it made real big power and torque. We are ging to try some new things with the heads and a different cam profile to make it better yet.

 

[Tyler Crockett]

Here are the pics with the stock efi manifold.

 

[Donskihp]

Talked to Don Hardesty @ Dart Machine works, and asked him if Dart had any plans to build any alluminum 8.1 (496) heads. His reply was if the demand is there they will build them. I don't know about any one else but I would love to change up mine for a pair of Alluminum performance heads. There lighter and run cooler!

 

[Wet1]

Talked to Don Hardesty @ Dart Machine works, and asked him if Dart had any plans to build any alluminum 8.1 (496) heads. His reply was if the demand is there they will build them. I don't know about any one else but I would love to change up mine for a pair of Alluminum performance heads. There lighter and run cooler!

You must be a fresh water boater. :sifone:

 

[Tyler Crockett]

Talked to Don Hardesty @ Dart Machine works, and asked him if Dart had any plans to build any alluminum 8.1 (496) heads. His reply was if the demand is there they will build them. I don't know about any one else but I would love to change up mine for a pair of Alluminum performance heads. There lighter and run cooler!

Don most of the 496 engines are closed water cooled so I don't think you will run much cooler with aluminum heads. You could get a little more agressive with the compression and timming with the aluminum heads but with the Mercury ecu you can't do that. Yes you could take 80 pounds of weight off the back end of the boat but that could hurt you more if you throw your center of gravity off.

 

[Donskihp]

NO, I boat in the Chesapeake bay, but with fresh water cooling alluminum heads should hold up well.

 

[Donskihp]

Tyler, Your probably correct about the merc ECU. My boat has gained some weight in the back, when I added the CMI sport tubes,and then some more when I added the Hardin thermostatic oil cooler. The whipple suppercharger probably did't add any weight. If I were to have new heads ported and pollished that would help performance without reprograming correct?

 

[Tyler Crockett]

Tyler, Your probably correct about the merc ECU. My boat has gained some weight in the back, when I added the CMI sport tubes,and then some more when I added the Hardin thermostatic oil cooler. The whipple suppercharger probably did't add any weight. If I were to have new heads ported and pollished that would help performance without reprograming correct?

Anytime you move more air you also need fuel unless you can raise your fuel pressure to make up for the air. You may run into a problem with it rich at idle or mid range or top end only.

 

[Fast-Trukin]

We are going to have a camshaft package with the heads for a bolt on power gain that will be real cost effective.

Thats what iam looking for..............:26::03:arty::grouphug:

 

[Tyler Crockett]

Thats what iam looking for..............:26::03:arty::grouphug:

We will be testing the new camshaft this week.

 

[SeaHorse24]

Tyler - How come the Merc MEFI 4 electronic control unit cannot be programed for more aggressive compression and timing? is this any different than the 500EFI ecu? - thought MEFI 4 was all the same?

 

[Tyler Crockett]

Tyler - How come the Merc MEFI 4 electronic control unit cannot be programed for more aggressive compression and timing? is this any different than the 500EFI ecu? - thought MEFI 4 was all the same?

The Mefi 4B we use has more tables than the Mefi 3. This motor has 9.1 to 1 compression and on 91 octane it does not like more than 31 degrees timing with a 107 cc combustion chamber.