8.1 Aluminum cylinder heads and other new products

tbyrne · March 5, 2004

This is a BIG POWER mod for your 8.1 motor! You'll be able to pick up 40+ horsepower and also take 100 lbs off the front of your truck with these aluminum cylinder heads.

Cylinder head specifications

Applications: GM 8.1 liter 8100 vortec (L18) engines

Mercury Marine 496MAG or 496HO

GM vortec Marine HP1, HP2, HP3 versions

Volvo Penta Marine GS8.1& GSX8.1 engines

Crusader 8.1 &8.1HO Captains’ choice engines

Indmar 8.1 & 8.1HO Malibu,Mastercraft engs.

Materials: Lightweight a356T56 Alcoa alloy aluminum

Heat treated and hard anodized for marine use

Method: Smooth cast

Machining: all required machining on 5 axis CNC centers

Valve seats: super alloy hardened high strength steel

Valve guides: manganese silicon bronze

Valve seals: super viton in steel "top hat" bodies

Valves: stainless steel EV8 with 11/32" stems, high flow necked stems with black nitride strength treatment after fabrication.

Valve sizes: Intake valve 2.20" x 12degree w/11/32" stems

Exhaust valve 1.725" x 20 degree w/11/32" stems

(Optional Inconel 1.725 exhaust valve x 20 degree avail.)

Rocker arm studs: Hardened steel with 8MM x 1.0 threaded top with

thrust nut base for mounting stock rocker arms with stock nuts, or

(optional) Raylar Stainless roller rocker arms with "all the way down"

adjusting nuts.

Intake Ports: 315cc. High velocity-High flow smooth ports

Exhaust Ports: 135cc.High velocity-High flow smooth ports

Complete Assembly: Includes:

Valves-intake & exhaust

Springs, retainers and locks

Valve stem seals, valve guides

Rocker studs and guide plates

Complete 5-angle valve job with

Back cut valves with special margins and radiuses.

Price - $2799.99 - free UPS ground shipping is being offered for all heads that are pre-ordered. We expect to start shipping these sometime in April!

A totally new intake manifold is in the late stages of development. It will allow much better airflow into this engine at all operating RPMs and allow it to develop more power and efficiency when combined with the new cylinder heads. This manifold will not create any added space considerations nor will it require any modification to stock or aftermarket marine configuration sensors, senders, injectors, fuel rails, brackets or hardware. Horsepower gains for the top end upgrades (heads and intake) will be in the 60-65+ range. More exact numbers will be available soon!

Other 8.1 products that you'll be seeing in the springs are - more aggressive cam grinds along with 1.8 ratio rockers.

Tom

tbyrne · March 10, 2004

Aluminum heads for the 8.1. One hundred pounds weight savings and a 40+ horsepower gain. Nobody has replied to this yet?

LikeaRock14 · March 10, 2004

I'd like some, but sadly I have a 454

They replied to it in High perf. didnt they?

8.1Texan · March 10, 2004

I'm a bit too financially challenged right now, but it went onto my "to do" list.

4x4man · March 10, 2004

Makes me really happy I bought a DMAX... $500 for 90hp and 250 ft lbs of torque...

tbyrne · March 10, 2004

Makes me really happy I bought a DMAX... $500 for 90hp and 250 ft lbs of torque...

Go away!

I like my big blocks but you guys do very well when it comes to power mods. Plus you also get twice the gas mileage.

8.1Texan · March 10, 2004

Plus you also get twice the gas mileage.

why do you think i'm financially challenged? paying for gas for my girl!

o4yukonxl · March 11, 2004

This is definitely going on my Christmas wish list. Are the numbers rear wheel or at the crank?

LikeaRock14 · March 11, 2004

Hey, think about it this way compared to the desiel guys:

If we wanted good gas mileage, we wouldn't have boughten the beasts. We knew the mileage would suck muhnkey bahlls. And they can't get that AWESOME sound a gas engine puts out w/ an aftermarket exhaust!

tbyrne · March 12, 2004

Those numbers are a rough estimate at the rear wheels. I'll post info after more testing is done.

4x4man · March 15, 2004

Makes me really happy I bought a DMAX... $500 for 90hp and 250 ft lbs of torque...

Go away!

I like my big blocks but you guys do very well when it comes to power mods. Plus you also get twice the gas mileage.

hehehehehe.

Well in all fairness, there is a $5k premium to pay for the DMAX engine in the first place.. I did have an '01 8.1L and loved it, but towing in the mountains and gas mileage were not it's best qualities. Oh well.

I see you have a Volant Cold intake for the DMAX, not to hijack the thread, but have you sold any, and have the buyers been happy with it??

Bob

4x4man · March 15, 2004

Hey, think about it this way compared to the desiel guys:
If we wanted good gas mileage, we wouldn't have boughten the beasts. We knew the mileage would suck muhnkey bahlls. And they can't get that AWESOME sound a gas engine puts out w/ an aftermarket exhaust!

You have a very good point about the exhaust sounds. I put a 4" exhaust system on my truck, and used a Magnaflow muffler in place of what I got with the system and it was WAY too loud towing. I don't even know how to describe it, but it wasn't anything I could get used to. I know I can't get the sounds of my souped up 5.0 I had out of the mighty d. We towed over the weekend and the wife and I pretty much agreed it had to go (the exhaust that is). Not ready to throw in the towl on this 4" system yet, but like I said on other boards, there has got to be a quieter way to drop 100-200 degrees in exhaust temp. If nothing else I am getting really good at swapping the stock exhaust back and forth!! sigh....

Bob

tbyrne · March 15, 2004

I believe we've sold a few Volant systems for the DuraMax but I haven't talked to anyone that has used it yet.

I kept the stock muffer on both of my trucks to keep them quiet. Just made them into split rear systems that exit under the rear bumper. Thye are finished off with very nice looking 4" tips.

Tom

2002 8.1 Silverado HD - Comp Cam, TOG headers, Volant induction, Direct Hits ignition, 8" lift ect... - 4.56s, 37s plus more coming soon!

2002 8.1 Suburban -Intercooled Whipple supercharger, TOG headers, Volant induction, 22" wheels/tires + more - 407hp/558 ft-lb torque at the rear wheels.

www.tbyrnemotorsports.com