109jb

I personally would not have replaced a single piston. Especially since a whole set of cast pistons is so cheap. Even though the replacement is a cast piston, you can't be sure that the weight matches unless you weigh it. I would have weighed it or replaced a pair at a minimum. Also, when you refer to the "old" engine, are you referring to this same engine prior to being rebuilt, or a totally different engine. If you didn't have the rotating assembly balanced, you can't be sure that this isn't the problem. Was the crank magnafluxed or otherwise checked for cracks? A cracked crank can go a loooong time and still operate but will cause these kind of wierd vibrations before it lets go.A cracked flexplate orflywheel can do it too. Another thought I had was mounts. Did you replace the engine mounts and trans mount? Lots of possibilities other than the carb. I personally like the Edelbrock carbs. If it does turn out to be the carb, it is most likely just a tuning issue, but I'd have to lean elsewhere.

Hope you get it solved.

John B

KBunny

I replaced the fuel filter today (and it was a little clogged) and that helped some, but the vibe is still there... the engine mounts are new (8 months old) and the trany mount wasn't cracked or riped when I checked it as I had the trany out just4 months ago.
As far as "old engine" usually means the 289 I pulled out to put the 302 in...

I would have replaced all of the pistons had I known that it had one bad piston, it wasn't until I got the engine back together that I found out that the piston that looked "ok" (minor scratches but my friend and I figured it was usable) turned out being bad but I didn't figure that out until it was in the car, at which point it was "do whats needed to get rid of the tick" and not a "well what about the rest of the pistons"...

I did not magnaflux the crank because the previous owner of the engine was an old guy who didn't drive it hard and it only had 60k miles on it with the cross hatches still on the cylinder walls when I rebuilt it, though it had been over heated (thus the bad piston). I also cut corners because I only need this engine untill I can save enough torebuild and build upthe 289 that I took out, so I went as cheep as I could.

Starfury

With one piston replaced and no dynamic balance on the rotating assembly afterward, it wouldn't suprise me at all if it's slightly out of balance, enough to cause a vibration like that in certain rpm ranges. Since you're building the 289, I'd wait to start throwing money at the problem until you've got the new engine in. Meanwhile you can tune the engine you've got to rid yourself of the driveability issues.

I actually have a similar vibration in my 67fb. Between 65 and 75 there's a harmonic vibration that varies with speed/engine rpm. Had the rotating assembly balanced before assembly, wheel bearings repacked last month, and axle bearings replaced when i did the gears,so I'm hoping it's the driveshaft or rear gears/bearings (which I could have conceivably messed up), both of which are slated to get replaced in the next couple years.

KBunny

The 302 is out of an 84 T-bird so its not anywhere near the 65-75 year range
One thing I forgot to mention is that the flex plates are different from the 289 that was in the car to the 302 in now.
Also (never thought much of it) the pulleys on the crank and water pump (water pump is about 2.5 years old/20k miles) don't rotate perfectly, I have noticed a little bit of a wobble in both of them but never really thought much of it. I can't imagine the pulleys making the engine vibe.
However I have reused those pulleys from one engine to the other, and given how perfectly the problems are the same I would say that it has to be something other then the long block for these problems.
I don't doubt I have some possible internal balance issues but I can't get past how the problems are exactly identical to what the 289 had when it was in the car.