Single biggest bang for the buck is the intake....Swap it, and jet the carb up and shorten your timing curve. A small carb really only hurts the top end. With the right squirters and jets, you can gain a bunch on the low end with what you have. An 850 will not have the size squirters or enough jet in it for that engine. We run #45's front and rear in all our stroker carbs once we get enough initial timing in them. #37 is the smallest we have run, and they are always lean that way.

Heck, we have been switching them lately to 50cc accel pumps front and rear just to get enough fuel shot in these engines. THATS when we really see the 60fts come down...But don't tell Thumper...

Shortening the timing curve varies depending on distributor, but the more initial timing, say idle around 22* and total in by 2500, the more fuel it will take in, and the snappier it will be. You will have to tinker to get this. We have used MSD and Firecore distributors, and both work well. Also, we have found ours like a lot of total timing. Not sure why, but my big 512RB had to have 38* total or it was .15 slower...

A 505 should be a beast! Our 512's are really nasty for a simple RB stroker. They idle well, and just fry the daylights out of a set of tires or slicks, let alone what they run on the track.

You gots to learn what it wants....read the plugs, put a wide band on it, try jet changes, tinker with timing....