Need some help on 6S1235

Recently completed a 5 year resto on 6S1235. Engine is stock rebuild, with only departure from stock hipo being melling blueprinted oil pump, Comp cams stock replacement valve springs, and Pertronix Ignitor I. Had issues with my rebuilt 715 Holley so following advice of several posters sent it to Daytona Parts Co. for full restoration. Have put about 200 miles on car since completion and has been running beautifully, up until a couple of days ago. Every time it starts black sooty exhaust for the first few minutes. I have read all the posts on Holley Lemans running rich and checked a few things however the car was performing really well. Took it out Sunday for a 4 or 5 mile jaunt and ran it up through the gears to about 5K RPM and turned around to go home and noticed it seemed to be loading up and not quite right, it stalled pulling in to my driveway briefly. Well last night I pulled the plugs (Autolite 34/BF32's) and the first plug was pitch black and sooty as were 6 others, however #3 cylinder and #8 were light tan/brown. Decided to try some hotter plugs and installed new platinum tipped 45's gapped at .040. Timing was set at 8deg advanced at 600 rpm, idle screws out about 1 turn. Took it out for a spin and it had bad hesitation on initial acceleration. Piddled with timing (couple degrees more advance, changed idle speed, messed with idle mixture screws all to no avail). Pulled new plugs same as old plugs 6 sooty, 2 kind of white. Cleaned and regapped some old 45's to .035 and installed set advance back where it was and idle screws out 1 turn, still the same. Valve lash was set cold on engine stand at .019, am running Rotella T 15/40. Think it could be a vacuum leak somewhere? Any help would be appreciated, Thx Kerry

Here's picture of car

 

Thanks for the advice, I'm going to check vacuum tonight, and will probably pull carb and check float height and needle valves. Puzzling thing is #3 and #8 look normal. Will probably check valve lash now that I have a few miles on it.

 

Interesting observation, hadn't considered...Thx

 

Thanks for the advice and compliments. Here's the latest in the ongoing saga, put the vacuum gauge on the port on the carb metering block and had zero vacuum at idle, realized this was a metered port, capped it and pulled the pcv hose off back of manifold and took vacuum reading. Found this animated vacuum page which is kind of neat, and I got exactly the result shown in scenario 3. http://sbftech.com/index.php/topic,3020.0.html Also found that the pcv hose even though clamped appeared to be loose enough to create a vacuum leak. rsimkins was on to something as that pcv connection is into the runner that feeds #3 and #8 so it was leaning the mixture enough to give me light brown on the plugs after fixing that I can proudly proclaim that now all 8 plugs are sooty. Pulled #1 spark plug lead put in a BF32 plug turned off lights and observed spark which appeared weak yellow. Installed my spare Pertronix flamethrower coil in place of taiwanese junk yellow top and observed bright blue spark. Still running rich but called it a night. Pretty sure somethings not right in the carb, probably a blown power valve or needle and seat or float. I'll update tomorrow. Thx

 

And now, for the rest of the story. Came home from work armed with 2 new power valves, non-stick bowl gaskets and needle and seats. Removed carb opened primary side first and instantly found the problem. Drivers side jet was laying in the bottom of the float bowl under the float, passenger side was finger tight. Checked secondaries and they were good and tight, very glad it was something simple though a little disappointed in rebuilder. Thx, to all who responded. Regards, Kerry

 

BillH....didn't see that you had posted prior to my last installment, thx for responding. The car was originally a white Hertz with an automatic and autolite carb. I bought the car when I was 24 (36 years ago) so that explains what happened next. Fuel pump went out went to auto parts store got the $9.95 fuel pump and left a Carter button top (Who new?). Next ditched the auto and replaced with a top-loader. Saw a Holley Lemans for sale in The Marque and bought it... has been on the car ever since. Somewhere in south Texas is an original Autolite carb and HiPo C4, I had stored spare parts in barn and somebody made off with them. Somewhere I have pictures of when it was "just a car". Wife drove it to work for a couple of years in the late 70's. My dad stored it for me at his place until I retired (semi-retired).

 

Will do, Thx Z