446 Mopar build. Cometic headgasket, retorque?

[Old Viking]

I'm helping on building a mild Mopar 446" with EDL aluheads, Lunati hyd FT cam 234/242 and 1.6 rockers from Hughes, 10.25:1 comp and dual 600cfm vac EDL carbs on a EDL dual plane intake. Both the heads and the intake has been ported. I'm using a Cometic .027" MLS Head Gasket to get quench down to .041" and ARP head bolts 70lbs. The engine will go on the dyno for tuning when its done, and the owner is hoping for 500hp with 1 7/8" headers. The dyno is a SF 901 and not at all a "Happy Dyno".

I'm hoping for 475+ lbs at 3500rpm as the heavy GTX will leave the startingline at that rpm. I'm a firm belever in making the most possible hp at the shift recovering point. It's a street and strip deal, and some kind of fuel efficency (12mpg HWY?) as fuel is expensive here in Sweden.

Now my concern, do we need to retorque the heads after breaking in the cam?

Brgds
Old Viking

[wyrmrider]

never hurts but I do not know about MLS on a BB Chrysler
BTW is this a B or RB?
if B long rod or short rod (that's still a long rod or a longer rod for Chevy lurkers)
are these roller rockers or
plain bearing with roller tip?
if so do you have industrial hard chrome shafts and bronze bushings?
you could go to the .020 gaskets if you have any detonation
what pistons?
block machined square? what surface for the MLS?
I'm getting ready to do one is why the questions
Motor currently has Mc Cord Marine gaskets
your motor should run good
AVS carbs I hope

[bigjoe1]

I never see a Cometic gasket respond to retorque. It is like a steel shim, there is nothing to give. I used to do the retork on Cometic gaskets , but now I do not ev en bother.


JOE SHERMAN RACING

[hodge]

I always retorque sometimes its just a matter of the heat cycles and shifting of the different materials

[Chipped tooth]

I have ran both Cometic and Felpro MLS gaskets in my mopars, boosted and nitrous.

I would torque them, then after a heat cycle I would go threw them again just for good measure.

Prolly not needed for what your doing but it can't hurt, I always check them while checking lash.

Fords we would check after every other pass on a boost application.

[Ron E]

In bracket cars years ago (also 440's) with OEM bolts on steel gaskets with iron heads and later studs with Felpro blue with aluminum. We settled on a couple of outings and we'd retorque. Usually, only the short (exhaust side) bolts needed it. The long ones stayed to spec. Maybe a little twist on the long ones were responsible?

[user-z68766209]

I never see a Cometic gasket respond to retorque. It is like a steel shim, there is nothing to give. I used to do the retork on Cometic gaskets , but now I do not ev en bother.


JOE SHERMAN RACING

What Joe said ^^^^^^^
Just to see I went back after 3 nights of racing and check them...waste of time.........

[Old Viking]

never hurts but I do not know about MLS on a BB Chrysler
BTW is this a B or RB?
if B long rod or short rod (that's still a long rod or a longer rod for Chevy lurkers)
are these roller rockers or
plain bearing with roller tip?
if so do you have industrial hard chrome shafts and bronze bushings?
you could go to the .020 gaskets if you have any detonation
what pistons?
block machined square? what surface for the MLS?
I'm getting ready to do one is why the questions
Motor currently has Mc Cord Marine gaskets
your motor should run good
AVS carbs I hope

I will get back to you in a short while on yr Q's.

Thanks everybody for yr quick answers!!

[gregsdart]

Cometic .027 mls in 549 bb mopar wedge, 15.5 compression, makes 980 hp, all aluminum, no retorque.