I am an HVAC guy and I HATE LEAK LOC.
It is a great sealant though.
***** to get off your hands and it stinks.

Many years ago I bought some allen head bolts for the intake on my hot rod (sbc). They were abt 1.5 threads longer than original and bottomed out just as the gasket started to compress. Changed the gaskets twice before I figured out what was happening.

Good thinking but I thought all sbc’s were open to the lifter galley and only need about an inch of threads depending on brackets etc.

OP did you pressure test yet?


I just looked this up. Not necessarily water leak related however covers some good intake/gasket info for those who care to read.
https://www.streetmusclemag.com/tech...manifold-seal/

My bad. I think you're right abt the intake/head connection. Now that I think abt it, the bolts I replaced were to attach the runners to manifold (TPI). A couple were a major pain thus the allen heads and ball-end wrenches.

Sorry took me a bit to get back.

I asked about the bolts and gaskets because many people mess this up since there are different style gaskets and thus bolts used for the vortec motors.

Def check the bolt length and don't be afraid to use up to 20ft/lbs torque with a normal composition gasket and non factory vortec intake bolts. The 12ft/lb figure came about from GM because of the OE plastic intake gasket. They'd even crush with the 12ft/lbs.

Also, as with most motors, if using a composition gasket thinly smear rtv around each coolant port of the gasket.

highplainsdrifter,
Old post but FYI.

I've had REVERSION ISSUES on my 502mpi forever. Spent many months trying to solve it. Looked at everything imaginable.
Finally extended the inner tube from the elbow(by welding on an alum extension). I added 6/8 inches at a time and tried it.

Finally, at 20"/25" extensions(slant cut), the reversion completely went away. Has always had condensation in the middle of elbow during winter/fall/spring, but no reversion. At least at the elbow. It does a little at the ends of the exh pipes but never reaches the elbow. Valves last way longer, especially in salt/brackish water.

Mine are stock except filters, exhaust, and bumped up timing. Have Eddie Marine alum log type exhaust. A friend has a little higher HP motor, 550hp, and had to go a couple inches further to stop the reversion. Good luck.

It's too bad that the OP never let us in on the what the resolution to this was. Maybe it was never resolved. I have the feeling this could be another cam or install issue.

Get a oil analysis. Get the oil up to temp not just Idle speed. Like was said raise your idle speed.

What risers are you using, standard or HP500 (hi rise)? Any spacers?
Thanks!

I don’t think it was ever resolved. It looked like had a lot of the parts from that engine for sale in the swap shop a while back - July of 2020.

https://www.offshoreonly.com/forums/...nce-parts.html