wzup1000

iTrader: (17)

Can I run a Ms4 with a cometic .040 head gasket on stock unmilled heads without flycutting? If so, how far could I mill the heads and still be safe?

Fifedogg

iTrader: (15)

Thats gonna be really close IMO. You should def. measure it before taking someones advice and guessing. Why dont you get your pistons flycut and not worry about it. JMO

PREDATOR-Z

No, no way

MS4 is allready beyond safe margins on a street hydraulic LS motor (Below .080/.100 recommended)

1bigcamdls6

iTrader: (2)

u guys sure? when my cam was put in and i took the heads off some time after that low and behold were a set of cometics sitting on my block i have replaced them with stock 02 z06 graphites but i had stock unmilled heads not sure wether or not they were .040

The Alchemist

iTrader: (19)

That's way to close for comfort, and FYI, cometics can come in a wide range of thicknesses for ls1 bores. Everything from 0.040 up to 0.065 I beleive.

PREDATOR-Z

Sure,

It is known that tolerances on a motor, varies from one to another. This is mainly due to piston deck height which can vary.
After a discussion with TSP way back, we came to the conclusion that PTV on MS4 is around .055 to .065 depending on LSA and motor.
Take .012/.013 (cometic .040 variance from stock) out of that and you are in serious danger of valve contact.

1bigcamdls6

iTrader: (2)

damn i didnt know that...tsp assured it would work with stock heads and it does but i didnt know it would be so close mine is on the standard 111 lsa but i dont wanna make this post about me...anyway

PREDATOR-Z

All BIIIG cams have tight clearances, TSP is not the only ones and some like Thunder recommend to check PTV on the T-Rex as standard practice (Bigger and tighter than MS4).
It is common knowledge that in the cam wars, it is all about stuffing the biggest stick in there to make the most power (not always the case) that attracts consumers and boost sales. Most shops will not tell you the margins because it will scare away potential customers. The usual phrase " yeap, it will clear, no problem".
Under IDEAL conditions, these tolerances are not a problem, but how many motors are IDEAL? That is the question !!

Jason 98 TA

iTrader: (4)

The MS4 does not need to be run with the .040" gaskets. The clearance is perfectly fine in stock form, but with a thinner gasket your asking for trouble. I've run really tight clearances in testing, and MOST of the really large competitors camshafts are even tighter than the MS4. That being said I dont like to see much tighter than the MS4.

Cut the pistons & stick some milled heads & a thin gasket on that thing if your wanting a big hp bump. The .040 gasket alone is worth about 5hp.