have twin 454s with quadra junks on them, one runs flawless but the other one is really starting to tick me off, it wont give me any rpms 3000 is all any more and it starts spiting and sputtering. have changed plugs, wires, coil ,distributer cap and rotor. starting to think it may have some trash in it, but instead of rebuilding may just replace both. whats a good swap, and do thay have to be marine carbs?

Holley 9022....its a 4150 base (will bolt right up)...its an 800 cfm marine carb...they were used on hp500 motors. You can get them with electric chokes or without. I put them on my last 3 motors....in my opinion, they cant be beat. Easy to tune, easy to clean, and easy to get gaskets and the occasional part.

I ran a Holley 750cfm 4150, elec choke, vac sec, secondary metering plate, quick change spring cap, on my 454 jetboat.
She'd cruise all day at 32-3300rpm on the primaries. Had the secondaries set to kick in at 3600rpm.

If you have a 370Hp Merc or less I would just rebuild the quadrajet, or get an edlebrock carb. If you go to a Holley don't get anything bigger than a 750, it's too much for the motor, IMO.

the motors are bored to around 498 cubes, the only thing still stock is the exaust and carbs. after i fix carb problem will do something with the exaust.

nice ride tinman thanks for input how many RPMs are the holleys giving you?

All depends on the rest of your combo...cam..intake..rockers..props...etc. If I were you..id put a 1" spacer under them (4hole), and id bet you'd have no problem turning 5400-5600 rpm's. All depends on your combo tho sir. Just a simple, great carb to work with.

Ha... You lied!... Those aren't 454's



I'm surprised that quadrajets ever made it to the top of your motors given the extensive upgrades.

I agree then... the 800cfm carbs should work nicely on your motors. I think you're going to notice a big difference with carbs and exh. They should really wake those big cube motors up. What intake/cam setup are you using?

Holley 4150 750CFM on a 330 hp 454. Mechanical secondaries, no choke. Check your fuel screen on the fuel inlet on the quadrajet, had the same problem with mine.

i replaced fuel filters checked inline filter and the screens, still runs like crap.