i just put in a 383 from a local machine shop, and it's been running pretty good. i've put about 250 ish miles on it since i installed it on wednesday, and the oil pressure stays at about 75, and the temp at around 190-210, which i was told to expect douring the break in period.

i was pulling into town today after a 10 mile highway drive, and when i stopped at a stopsign, the motor hesitated, and died. i put it in park, and started it again, and when i left from the stop, there was a large cloud of grey smoke in the intersection.

as i drove through town, the oil pressure went down to 50, and more smoke came from the exhaust pipe on the drivers side. i parked it on a level driveway, and went out about 10 minutes later and checked the oil, to find it was a quart low. it hadnt leaked any onto the ground, or down the motor, so i'm pretty sure it's being burned.

there are no knocking sounds or other strange noises coming from the motor, and at 55 mph, it still reads 75 psi of oil pressure, but since the smoke is only coming out the drivers side bank, i'm thinking it might be a bad oil ring, or be coming through a valve guide. also, the smoke is only noticeable when leaving from a stop, or accelerating from low speeds.

the motor is under warranty for the first year, and i've only had it a week, so if it is a real problem, it shouldnt cost me anything. it does have a fairly meaty erson cam, and i know some oil burning is expected, but i am concerned about it only coming from one bank, and all at once from a stop.

any advice would be greatly appreciated.  

An oil ring installed wrong or broken sounds like a good idea to me.

Take it back to them and have them do some warranty work!

Even though it doesn't really apply to your problem, you do know that a flat tappet cam needs a break-in period IMMEDIATELY after it's started for the first time, right?  

yeah, we ran it at 1500 rpm for 30 minutes when we first started it to break in the cam. thats what the guy from the machine shop said to do. i hope it isnt the oil ring, but if it is, it's under warranty. i work full time at another shop, so my boss can tell me what it is for sure, ans i'll call the machine shop tomorrow. this really sucks. i was so happy when i got it running, and for a while it was like having a new car, but at least this happened under warranty.

here's the pictures from the swap. i had them paint it 'ford red' to match the stripes on my car.

http://s302.photobucket.com/albums/nn108/ejmurphy90/350%20to%20383%20swap/  

Sounds like either it's got a bad ring, or the valve seals on the driver's side bank have failed. Regardless, don't wait around, take it back to the builder immediately so you don't risk him trying to void the warranty because of anything you did, even if it didn't cause the problem.  

just curious...      how did you run the spark plug wires to the # 5 & 7 cylinders. back two on the drivers side....  are they separated or did they get run together side by side all the way to where they separate at the spark plug...


many times  on both ford and chevy motors where the 5&7 on a chevy and 7&8 on fords when the wires get run together for any distance at all they will induct a pulse of current into the spark plug wire next to it...  causing the spark plug to fire 90 degrees of crank rotation early..


when this happens... it tears up the piston in the last bore on the drivers side.. (left side)


on fords since the wires run from the front of the motor... the wires should be run over the edge of the valve cover in this order... 7,5,6,8    this separates them enough to reduce or remove the problem..

on chevys...  you can do the same thing... in a holder ... or if you think about the factory holders... they move the #7 wire away about an inch from the others....

on a fresh rebuild... the pistons may be tight enough to not make any noise when this happens...

you can tell if it has damaged the pistons by doing a compression test.. on the drivers side...   a cylinder leak down test will also be of help...