360 engine smoke

No, it should not smoke. I have KB pistons in my 360 and it never smoked. What condition are the valve guides in? also, is the intake sealing good, not sucking oil into the intake?

If all eight of the plugs look exactly the same, I'd be leaning away from the issue being with the intake manifold gasket and valve seals.

First and foremost, as mentioned, perform a leak down and compression test.

What I would be thinking about now is did the machine shop set the gap correctly for the top piston ring. Are those pistons hypereutectic? If so, they require a different gap than cast and forged pistons.

yes they are hypereutectic pistons. i recieved the car like this so im not sure what machine shop did it. also i just put a different intake on it and it still smokes so im guessing it isnt from the intake. it also smokes alot out of the oil breather when idling if that changes anything. i havent done the compression check on it yet thats will get done this weekend. i appreciate all the help and will continue to update all info i can. thanks

What kind of intake gaskets did you use? I had trouble with mine until I got some composite Felpro ones.

http://www.summitracing.com/parts/FPP-1243/

Just for the heck of it, check if the PCV valve is functioning properly. Is it open and pulling manifold vacuum?

OK i just pulled my plugs again after a little ride in it and the front 2 plugs on boths sides are covered in oil and the back 2 on both sides are a little oily but not soaked. what direction am i looking towards.

ok thank you everyone i will be doing the compression check this weekend and ill let everyone know the results and hope i get this figured out.

ok i just did a compression check and this is the results.
cylinder 1: 150
cylinder 2: 150
cylinder 3: 120
cylinder 4: 155
cylinder 5: 110
cylinder 6: 135
cylinder 7: 110
cylinder 8: 135

not very good results here. the smoke has gotten less but still smokes. im guessing rings not sealed up right?

Do the old car lot trick of dumping a handful of Bon-Ami cleanser down through the carb while it's running. I know it sounds funny but I've seen it seal rings that wouldn't seal. lol

I'm bringing this one back from the dead to ask about my 360 smoking issue.

Build is 360
KB107 pistons
340 rods
596 heads
Comp XE268
Performer Intake
Eddy AVS carb

I built the motor. Rings were properly sized and staggered.

The motor has at least 2k since the rebuild and runs super! After cruising awhile, it'll smoke heavily upon hard acceleration. Once it's "blown out", it won't smoke for a bit. Then after some more cruising, it'll smoke again on hard acceleration...etc, etc...

It also seems to use a quart of oil every few hundred miles or so and the oil seems to stay pretty dark, even after an oil change.

I've replaced the intake gasket once with no change.

I bought the heads "already done" and to be honest, never even looked at the valve seals.

Thoughts? Valve Seals? Rings?

Thanks. Good read. But there's a lot of contradictory info here. What about cam break in? What about tuning? These things have to be considered before just firing up a new motor and beating it around the block to break in the rings.

Either way, when I fired this up for the first time, I broke in the cam per Comps instructions. Then, I have to admit, the first several trips around the neighborhood were quite "spirited".

The one thing that does stand out to me though, is the honing job. Perhaps my machinist had it too rough...

Will a compression test tell me if it is indeed the ring seal? What should I expect to get for compression?

Oh, and I've checked all the plugs. They all look pretty clean. No carbon or oil build up at all...

Thanks again for the help!

Bumping this back up for discussion as it's time to tackle this issue before cruising season. Anyone have any feedback on my previous post regarding what to expect from a leakdown/compression test?

Sounds like you probably have a broke oil ring. That usually happens upon installation, not so much while "breaking in". I wouldn't be suprised if you pulled the heads and saw a groove in one or more cylinder.

When you installed the intake manifold did you cleanup all the old gasket etc/ While not disagrreeing with all thats been said I have found small blocks to love to draw oil in from the lifter valley. The gasket sets say never to use any sealer on the port sides. I ran into similar problem twice both times went and got the thickest intake gasket sets and used Indian head gasket shellac on the port sides. Went from oil smoke to zero. I have seen engines with broken rings not smoke that bad. Just my 10 cents