I wouldn't be getting them made if they didn't fit.

This might be a little more than you're interested in. The stock pulley is bigger than 3.75" I think its 4-1/8" The 3.5" whipple pulley should make 12 psi. I only saw 10, but I had a non blower friendly cam that bled some off.
The stock pump is more than enough for the 42# injectors. I ran my 44# injectors at 120% IDC and the pump kept up just fine.
I'm considering a 3" pulley which would probably make around 16 psi on your setup. I wouldn't recommend doing this on a stock long block. I added some cubes and need to pulley down to compensate for it.

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