Engine vibration question

[Jack21]

The continuing saga. Spoke to the machine shop that did the engine. "Bring it in and we'll have a listen - feel, see what it might be."

Meanwhile, I'm juggling mufflers. Reinstalling the 30" set so I can send the 36" set to coating shop. Notice a fast idle stumble in process of cranking initial advance up a couple of degrees. Out with the vacuum gauge for lean best fast idle. Open the screws about a half turn, vacuum comes up, stumble goes away. (Per the Holley instructions on leaning out rich idle mixtures, I'm adjusting the idle air with the secondaries, while leaving the primaries below the transfer slot. As a last resort, I'll drill air holes in the primary butterflys, but we'll try this first.)

Next day. Idle has a little more lope to it, but vibration at 1700 is gone, - completely! This, to me, eliminates any engine imbalance problems. My major concern, hauling the engine out and back to the machine shop (and possibly missing DVSFII) is gone. That's a relief. But I may be twiddling with this Holley (700DP) getting the idle, and off idle mixture dialed in for awhile. (but, my gawd, the acceleration!)

Fuel economy is running 14.5 to 16 MPG back & forth to work, inching along in traffic backups, and around town, and plugs look good, so nothing is grossly off. Will need an exhaust gas analyzer to dial it in any tighter than this.

Car is coming up on 5000 miles, and front suspension that I thought was overly firm, is settling in. Would still like to covert front shocks from Carrera to Koni, but not an immediate priority. Getting upper control arms to stay planted after an alignment is my next priority.

As much as I bash CR for it's shi**y engineering on some things, they did well on weatherproofing this car. I expected a myriad of water leak problems driving in the rain. Passenger compartment stays dry, even at 60 - 70 MPH. I expected water on the distributor to stop me dead with the first heavy rain. Nope, dry. I expected water in the air filter to be a major headache. It's the Edelbrock oval with K&N filter. No problems. Defroster & Lucas wipers work fine. Falken tires work as advertized, plenty sticky on wet roads. One problem, wet brakes, no backing plates. I'll start another thread on that one.