A friend ov mine got sold a 670 version for his stock 440 (76 engine in a 73 Satellite). It was bone stock except for a open element filter and a recurve. It ran great out ov the box, needed very little tuning/tweaking (i think i played with the jetting and the secondary springs), but it was definitely too small for even a stock 440. Great throttle response and got considerably better mpg than my own stock-ish 440 with a 750 vac secondary. I still have it... keeping it around in case i even have a small block in need ov a good carb.