In principle, you could extend it to achieve a collection aperture big enough for your range. This would require the basic unit to be rather high and the baffles somewhat harder to reach for cleaning. The angle of the extension pieces must be sufficiently close to vertical that effluent reflects upward when impinging on the extension. This makes the collecting aperture of the liner rather high, and the overall assembly rather large. Cabinetry may help obscure this.

Whether 1200 cfm (at zero static pressure drop that you won't achieve) is adequate depends on many factors, but it might be risky because with a large aperture, the velocity of the air at the aperture might be relatively low and not helpful for containing the effluent. On the other hand, as the effluent rises and narrows in the hood, when it reaches the baffles the air velocity will be higher and perhaps adequate. I would be concerned that with significant cooking ongoing, rising effluent from multiple sources would not be contained, as may be seen in published Schlieren photographs of commercial units pulling insufficient cfm.

Conceivably, a second helper fan inline with the ducting or mounted to the roof could be used to boost flow. Methods of control of both fans would need to be considered.

Your trade-off here is avoiding the loss of the liner purchase price and committing to a lot of time to ensure a bastardized design will work, along with a lot of additional cost for parts and welding, versus just buying the right assembly and possibly reselling the unneeded liner.

The liner capture area should extend beyond the cooking zone such that rising and expanding effluent intercepts the aperture and not the area outside the aperture where it will not be captured. A 66 to 72 inch liner will be needed.

In any case, don't forget the need for make-up air.

kas

I would use the liner you have, just make sure you recess the liner up inside the wooden structure be 6".

The capture area should be 66" x 27" possibly set 32" - 36" above the range top dependent on local code and the height of the people using the range regularly.

I doubt you will need make-up air, but you may want it.

Code may require MUA for any fan over 400 cfm.

More to the point, if you are going to get anything vaguely near 1200 cfm through that hood, new air has to be available. Where will it come from?

Much depends on what/how you cook, and the design of the house. But if you are really want to use that nice big griddle, consider a new, bigger liner, a blower rated above 1200 cfm, and at least 10" ducting.

Think of it this way: If this turns out to be overkill, you'll simply end up running the blower at less than full blast when you need it. But if you end up with inadequate ventilation, fixing it will be expensive.

Really, you only paid $875 for the liner and blower. The blower usually goes for over $500, and you can still use it. Do it right, sell the liner and buy a larger one.

Thx for the info guys. So I can keep the blower and just buy a 60 inch liner? I have a guy that wants to sell me a Best liner. Are these comparable to a wolf?