i was riding in my friends boat and under boost i swear i seen water coming from the heads were they meet the block when he got on the boost hard! on all four heads at the same time! ticking time bomb i know. it doesnt leak under regular driving etc what should he do new head gaskets and apr bolts or studs?

How manny boost? what is your water pressure?

Sounds more like a water pressure issue or possibly sealer was not used one the head bolts.
Pull head bolts one at a time, retorque to spec and use sealer on the ones that go into water jackets.
I think if the head was lifting, it would have already burnt through the head gasket between cylinders.

doesnt have a water pressure gauge/ was at 5 boost

i agree with griff,in order to raise the head for water to leak,the head gasget would be blown,install a water pressure guage before taking the boat out again.

I like head studs for the few extra bucks. And like was said, if any bolts/studs go into a water jacket, a good sealer must be used.

Water PSI gauge is mandatory for something like this

I wouldn`t worry about it, you buddy probably has one of those new water cooled head gasket kits installed.

you have already gotten good responses, under boost the head gasket will fail between at #3,7,2,4 usually allowing water in lifter gallery milking/frothing up oil
this is the weak link on a chevy bb as the spacing between head bolts is the largest in these areas
We switched to dart big M or world pro blocks to eliminate this issue they have provisions for an extra bolt at these areas ( of course you either have to tap and drill heads to receive bolt or use after market heads they are already set up for this)
it invariably blew at number 2 for us until we switched this up then ran 8-12 lbs no issues with gaskets
you can "O" ring block which works also but adds cost and complexity

all this being said I would have to agree that you have too much water pressure at speed I have seen 100 psi spikes , anything over 35 we added dumps to relive pressure or you will have ( usually intake gasket problems)
cometic gaskets are more resistant to boost related problems also
arp head studs are a must

we are installing a temp water pressure gauge. will put it were the water drain is on the side of the block. is that a good spot? keep in mind we are only seeing 65 mph at 4900 rpm. with trs drives

At those speeds I doubt that it is a water pressure issue you probably have a leak around a head bolt. 5 lb of boost is unlikely to lift the heads unless you don't have them torqued properly. No need for expensive blocks and head studs at that boost level so long as you have good ARP head bolts. Just my opinion. Good luck