I have access to a Marine Q jet for a reasonable price. Does anyone have
experience with one on a street car? Any advantages or disadvanges? I
don't have a number for it yet, but am told it's for a 454. Would that make it
an 800cfm variant.

Help,
Owen

 

I acquired a marine QJet back in the 80s when I worked at an auto parts store - someone brought it is as a core and I bought it from the store for the $6 core charge. The main thing I found was the secondary metering rods were the thinnest (richest) I have ever seen, with zero taper, just an abrupt transition from fat to thin. I suppose this is due to jet boats running at either idle or WOT, with no load or full-load, so there's really no need for part-throttle jetting. Can't remember much about the primary jets/rods, but after changing those and the secondary rods to the same that were in my 70 Supreme, the carb worked fine on my car and then later on my friend's GMC Jimmy.

 

I just finished rebuilding one for a friend. Not really anything different about them other than jetting and metering rods and they have an extra fitting for what we call the "puke" tube that comes from the fuel pump to kill the engine in case the diaphragm breaks.
They are all "Chevy" style with the fuel fitting off the side instead of in front like Olds is.

I don't think any of them were 800's

If you have the part number you can probably find it here: https://www.marinecarburetors.com/collections/quadrajet
Get a picture of it also, very common for them to be pretty corroded depending on where the boat was run.

Used Q-jets are almost a give away around here so I sure wouldn't spend too much on one. One of my customers called the other day and said he was taking about 20 of the to the scrap metal place and asked me if I wanted any of them. I passed.