The Weber carters are smaller then the holly Weber 32/36. They are entirely too small for a 292. The 32/36s are also small, not as small as the carters, but will work. The 38/38s will not really work all that well with adaptors on a 2x1 Intake. I have rpthe 38/38s on an old style 261 motor and they run great so no problem with a 292. Let me encourage you to reconsider the Clifford set up. The manifold is cast with an internal heat chamber so no plates to leak or any mess like that.
And yes, you can handle the lump port yourself but if you want someone to install them, try member tom Lowe. He makes lumps and does installs and other head work. Use someone who is familiar with hopping up these motors. You will be heads and hands ahead in the long run.
