Which Quadrajet to swap ?

[Mike D]

Now you are cooking! See if that Holly replacement has an adjustable vacuum secondary. The biggest deal on a 4 barrel is to set when the vacuum secondaries will kick in. Too soon - bogs down. Too late - slower acceleration. It is all trial and error. If it is not adjustable order the vacuum secondary spring kit. Lay out the color coded springs in increasing tention. Start in the middle, if it boggs go to the next higher tension. If it does not bog go lower. It's that simple. The spring tention sets the vacuum for the correct moment when the secondaties should open. This also corrects for engine condition ( wear and tear ) for best performance. Good luck.

 

[jonrpick]

Now you are cooking! See if that Holly replacement has an adjustable vacuum secondary. The biggest deal on a 4 barrel is to set when the vacuum secondaries will kick in. Too soon - bogs down. Too late - slower acceleration. It is all trial and error. If it is not adjustable order the vacuum secondary spring kit. Lay out the color coded springs in increasing tention. Start in the middle, if it boggs go to the next higher tension. If it does not bog go lower. It's that simple. The spring tention sets the vacuum for the correct moment when the secondaties should open. This also corrects for engine condition ( wear and tear ) for best performance. Good luck.

While it would bolt up, how well would this carb perform on the trail compared to the Q-Jet? (which is the OP's requirement)

One of the Q-Jets (many) strong suits is it's ability to work well at odd angles. I'm sure the Holley is a great carb, but having a spreadbore wouldn't necessarily make it the same otherwise.

I ask because I've seen these carbs before, but you're the first person I've known to actually have one, although on a street vehicle. So I haven't formed any opinions about them...

 

[RaisedK5]

Stock for your 74 should be a 4MV model Q-Jet.

It should be one of these:

I would take these numbers to a reputable carb shop and tell them you want the stock carb for your truck. If they cant get it, they can look up the specs and build one from a good core. Or you could try your luck with one of the chain stores and the carb number, but a carb shop would be able to tune it, and set up an electric choke , or get the correct divorced choke that came stock.

 

[Mike D]

From my experience with Q jet get one with the electric choke built in and adjustable. The divorced choke models do not work well if you have an Edlebrock intake manifold . The location of the choke well is one inch too far back. The linkage from the choke coil in the well to the carb attachment is at an angle, not straight up and down. Regardless of how you bend or adjust the connecting rod it gives unpredictable movement. Example - in the morning when everything is cold the choke may or may not come on. when warm the choke may not completely turn off, this prevents the rear barrels from opening. Thats not to good when you want full power.

I am in agreement with you - the Q jet is the best carb for off roading.

 

[RaisedK5]

I had to make a new choke rod becasue of the raised choke pad on the 2101 manifold, but in 15plus years have never had a problem with the choke not operating properly or having alignment issues.

 

[Jesse Jaymes]

Thanks for the assistance in cutting down on the research. Off for a week to WA, then I will dive into it when I come back. As well as my 205 will be here waiting to be swapped. So I am sure I will have more questions.