highplainsdrifter

Trying to figure out why I am getting reversion when based on everything I know I shouldn't be. Most likely something I have done wrong, but I cannot figure out what.

Here are the engine specs

SBC
9.4:1 compression
Davis Unified Ignition (base timing set at 10 degrees)
Edelbrock e-tec 170 heads with 1.52 roller rockers
Comp Cams xms270hr cam
specs in attached picture
Brand New custom, very long risers from Stainless Marine (picture attached)

I am new to assembling engines. I purchased this short block directly from GM. I installed the cam and the heads etc etc. The cam was installed 'dot to dot'. I went through the steps to degree the cam. I was fuzzy on the process but had all the tools and got some numbers that told me I was good and left the cam straight up.

I went through the process to make sure that rocker arm geometry was right and got proper length pushrods.

The boat starts and runs with ease. I have not had it in the water yet.

Is there something I could have done wrong during cam installation that would cause this?

Any ideas on where to go from here would be greatly appreciated. I was thinking the boat was going to be in the water next weekend, now I am wondering if I am going to have to pull the engine again.

Here is a picture of my risers:





Here is my cam card:




Here is pictures of how much water is in my manifolds:





Thanks,
Russ

GPM

Where does the riser dump the water ?

highplainsdrifter

Right at the bellow hose connection to the tailpipe all the way down at the transom.

AllDodge

iTrader: (1)

Are both sides wet?

highplainsdrifter

yes, both sides the same amount of water.

highplainsdrifter

Here is a picture from the other manifold

AllDodge

iTrader: (1)

I think you have way more rise then needed for reversion to be an issue (emptying out at the ends), so I'm wondering if there is something wrong with the new pipes

highplainsdrifter

I was wondering about that as well even though Stainless Marine has a great record of quality.

I am not sure how to properly test a pipe, but what I did was hook a hose up to the water inlet and turned the hose on all the way with very good water pressure and no water came out at what is supposed to be the dry end (where it connects to the manifold).

If that is an adequate test, then I think the pipes are fine.

I really appreciate the help! On my own, I am at a loss at this point.
Russ

Twin O/B Sonic

Do we know it’s not leaking head gaskets blowing water out of chambers??

PS, good for you thinking to ck this before lighting it up and eating a motor.

highplainsdrifter

I'll go do a compression check and also check to see if there is water in the oil right now.

Thanks again