Like I said in my other reply on the first thread, I don't think that 650 won't be enough carb for you. Again though, it really depends on what cam you have, what you're intending to do with it? etc.....In other words, is this going to be a daily driver or a racer?

If you aren't climbing up over 6500 rpms a lot, the 650 will really be (as techinspector mentioned) too much already; but it can be tuned down. Throw an 850 on there and you'll find that you'll be jetting it down and tuning it way down and probably still have problems with it. Your motor just won't huff enough air to make it work right. Carbs that big are for Big Blocks or racing small blocks that get wound up really high and have rumpety rump, radical cams, not driver small blocks that rarely get above 3500 rpms.

Try Holley's calculator for yourself and I think you'll see what I mean.

In the end if you really have to have an 850 on there just for the "yeah it's got an 850 on there" coolness factor, I really think you'll be way over carb'd and have problems with it. That's just my opinion though and I don't consider myself an expert.

Good Luck,
Dutch