Whipple 2.3 - is it too small for a 540ci Chevy? I have the setup on a 509 cid deal, but might swap cranks and pistons out, and was thinking about bumping it up a 1/4" on stroke.

It is on the small side even for a 509. I'm sure it can be made to work, just not optimal.
People put B&M 174's on 502's and they are maxed out only will make about 4# of boost, but still add power over being N/A.

I highly modded the 502 mag intakes,more than most,I even cut up the opening and exit on whipple's intercooler,w/ 490ci and I only get 4.5psi.If I were you,I'd look fo a 3.3.

A whipple 2.3 maxes out pretty early. I built a pair of 454s that made 785 hp at 9.5 psi of boost with I think a 2.9" pulley. I put a bigger pulley on it because of high IAT concerns and longevity. I recently dynoed a 515 cu inch motor that also had a 2.3 sidemount. Customer had a 2.7 or 2.8" pulley to get it to make 5.5 psi of boost around 800 hp, BSFCs were completely awful too because of how hard the blower was turning. Im thinking we were seeing .700+lb per hr per hp. I wouldnt consider putting one on anything bigger than a 4.0 stroke combo, thing was really too little for the 515, fwiw, Smitty

Sorry to hijack thread, but planning to put a whipple 3.3 on a 540. Hoping to make 7-8 lbs boost. Bad idea or OK?

Depends on how well built the 540 is, and components used.

All new, Built for blower, dart block, Dart heads, blower pistons etc.

if you can spin it at like 30,000 rpms I think it`ll be just fine.

seriously ,how fast can you spin a 2.3 whipple .
I am going to put one on a 540 also

Spin it too much and it becomes a heat pump and not efficient. better off selling the 2.3 and use the money towards a 3.3.