I've got a factory '57 bird holley and intake for my stock 292 in my daily driven '59 galaxy that i'm going to be putting on in the near future. I'm now looking at throwing a McCulouch on there for a little more go. I know these carbs are an odd ball as holleys go given the dual power valves and such but i was wondering if there is going to be any other hassles besides the the typical stuff to convert a standard 4150 to blow thru.

If running a 4150/4160 Holley as a ‘blow thru’ carb, then you’ll likely need to run a double pumper carb rather than a vacuum secondary carb.  The vacuum secondary diaphragms on the 4150/4160 Holley carbs do not lend themselves easily to boost referencing the secondary diaphragms.  If the carbs have brass floats, then those will have to be changed out to the solid composite style floats.   If you're not a carb guy, then purchasing one of those carbs that’s already calibrated for a ‘blow through’ application will have some of those mods already performed as well as having an improved fuel calibration.

Lorena, Texas (South of Waco)

Good points ted, i do have a number of mechanical secondary carbs sitting around i could steel the shafts and linkages from, or i have a mechanical secondary conversion kit on a spare carb i could install (i believe it's an old eelco piece)

As for the floats, is there really an issue there when dealing with a low pressure setup? Ive read it in a few articles. I doubt there are plastic floats for the early style bowls

Shaggy, PM sent about my carbs.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

The brass floats are easily collapsed with nominal boost pressures.  Rather than trying to run the original List 1273 carb, I’ll suggest going with a slightly newer carb that has externally adjustable needle seats.  The solid style floats for those carbs with externally adjustable float levels are much easier to come by.  As a sidenote, the original 1957 Holley carbs tend to be undersized in boosted applications so a larger carb will be called for anyhow.
 
Here’s a quick story about those floats.  Chuck Cline was running his blown ’56 Vicky at Columbus one year when he collapsed one of the original hollow brass floats.  No excessive boost levels here.  Needless to say there was a sudden flooding issue with the carb.  By luck of the draw, I carried spare ‘solid’ floats in my trailer and it was a simple job to change them out.  That fixed that issue.

Lorena, Texas (South of Waco)

I M H O. & I readily admit I'm no supercharger expert.. but based on information posted here over the years & in Y-Block magazine, just "throwing on" a Mc Culloch, will be a tall & expensive undertaking!. Obtaining all the needed pieces & the expense of them is a big issue!.  If you just want to pep up your engine some, there are currently parts & methods available from people like John Mummert, that can more than do that, likely cheaper & with less headaches.. As for the original T.Bird carb, best put it back together or whatever & sell it to someone doing a restoration...   


Paul