tahoeguy318

OK here we go...Last season I noticed an excessive amount of steam coming out my exhaust so at the fear of a head gasket leak I am going to replace them BUT[B] I figured while I am at I will refresh the engine a bit. Keeping my budget around 1000 I have decided to put on vortec heads and a edelbrock airgap vortec intake manifold. Then engine is a 1989 350 magnum and my question is what thickness/brand of gasket should I use to get optimum quench for maximum horsepower ? I thought it should be very thin like .015 but the only one I have seen so far is .051 which is much thicker and I think that will make way to much quench? thank you
Harry

Sadist

Be careful, those vortec heads in most cases have very small combustion chambers, from the factory, the General opts to use a dished piston and still makes 9.4:1. your current engine most likely has a flat top with 4 valve releifs (eyebrows) on the piston top and is about 9.0:1
What cam do you intend to run?
What kinda gas is available to you (at all times)
check this link for info on head cc sizes http://www.mortec.com/castnum.htm
SCE gaskets specializes in "shim style" gaskets, they offer a steel .015" gasket for the 4.100 bore size smallblock (part no. 511101) you might want to talk to their tech dept though.. it is not clear in the catalogue that this gasket will work with the Vortec head. (1-888-427 5381) or
888 gasket1
Attatched a confusing, but useful scan of a comp ratio chart from the back of their cat..
G'luck
Sadist

The scan is legible (barely) once you expand it to full size.
I can email you a better scan... but I think a .015 is a tad too much.

Griff

The head gasket would be last resort to check for your steam problem.
I would check your exhaust and especially the riser gaskets first and then the intake manifold gaskets.

tahoeguy318

Thanks, As far as camshaft goes the stock one that came with the engine is in their now...I was thinking about changing that out too but, not sure yet...was thinking maybe a mild cam what do you recomend? also as far as gas goes, I trailer the boat so any octane is available!
thanks again

oh and as far as the risers and manifolds go I changed them last year but will definilty be taking them off and putting new gaskets on!

Sadist

Email some of the folks that offer the Vortec heads.. (Big GM dealers) and ask them what the CC of the heads that are available, and what compressiom rato would be expected by the combo with your piston top (i assume flat top 4 eyebrow). I think the number is just under 10.0:1 with a typical (non shim) gasket then cam accordingly.. (280^(MAX)duration .460 lift, keep around a 110^ lobe separation or pay dire consequenses With the air gap manifold and roller tip rockers.. it'd be a strong 5500 RPM runner I'd guess at 340HP and a slave to 94 octane
It sounds like you're pulling at straws to find an excuse for building some more power no harm in that.. and the "old lady" is easilly fooled by such shenanagans..
Griff is right-on, head gasket is unlikley the cause of the steam.. Unless you've gotten her "hot as balls" in the past.
have you noticed a performance loss, and perhaps are milking oil?
Steam all the time or only when you get on it?
Headgaskets on smallblocks typically let go between cyl's 3 - 5, this is the hottest point of the engine, the last side to get water, and exhaust valves are close together, this is also where heads crack.
Borrow one of those infa-red heat guns.. (or buy one ya cheap bastid.. they're less than a hundred bucks now) and spot check the risers, they should be nice and cool, like less than 100 degrees.
(when you replaced the risers last year, you did use the gaskets with the restrictors in them... right??? If not, there's your steam, water's flowing out of the system too quickly and not lingering long enough in the manifold to absorb heat)