possible reversion ?
 

I ve got a 383 stroker i just built with comp cams xm276hr roller camshaft in276 ex230@50" lift in.503 ex.510 lobe sep.112 Im also running a set of glm alum. manifolds and risers.The problem im experiencing is sum times when i go to start the engine it will start to crank over and then it locks up. It might do this 2 or 3 times before it starts. Im kinda worried im getting a little water in the cylinders and getting a hydrolic lock. Was wondering if anyone has seen or heard of a similar problem.

I had that same cam in my 383 and I didn't have any real reversion issues, but at tear down I did have some evidence of water in the cylinders. I have some minor rust lines in corresponding to where the pistons would have been. I figured it was condensation from the exhaust riser dripping down into the ports. Only had this on one side.

What intake, carb, and heads are you running?

I should add though, I had below swin exhast exit. If you have straight out the back, you quite possibly have a big enough cam to pull water back on a slight slope.

I ran that same cam only with 1.6R on the intake two years ago on a 355ci SBC. I also ran GLM manifolds but with FastGlass Stainless Performance short risers. I had reversion at idle. After 45 secs of idling there would be small puddles of water in the center runners. I had to weld 16" extensions onto my risers to get rid of any reversion. With my current 385ci I run a custom hyd roller 234/240 .580/.568 112+4 and have 22" extensions. The water does not meet the exhaust until inside the tip.

Only way to find out for sure is to idle the engine for a mine and then turn off. Then pull the riser and inspect. It does not sound good when you say locks up. Water does not like being compressed and usually results in a bent rod or worse. HTH

Im running vortec heads /edelbrock vortec rpm air gap intake and a edelbrock 600 cfm carb. I thinking about getting a 750 holley.

Its strange it doesnt do it everytime. Another thing ive noticed is i dont have near as much water coming out the exhaust tips as i did with my 355 running comps xm270hr which is the next smaller cam running stock merc exhaust.

What RPM are you idling at? Maybe you just need to bump the idle speed up to 800 or 850. I don't think the apparent change in water out the tip has any relation to this.

I was thinking about hooking up the mouse ears in the drive to see if i can get it to lock up and then pull the plugs to see if there is any water in any of the cyl.

Its idling around 750 to 800 rpm