440 - thermo-quad or not to thermo-quad?

I've got a '78 motorhome with a 440. The old thermo-quad carb needs replacing. My question, should I replace it with another thermo-quad or is there something better? Improved performance would be a welcome benefit. Thanks for the help.

hey tom, if u have a carter afb 625 now, i think u do, i'd stick with it if you have had good luck till now. i had a 73 440 with that carb and had great luck with gas mileage( if u can believe that) and cold starts. the idle mix screws at 2 turns out from bottom worked great for me. hope this helped...good luck, (440 was a champ of a motor!)

I personally like the Holley spread bore replacement,but the Edelbrock Rochester replacement carb looks very interesting too.Have you thought about Holley's throttle body fuel injection kit???I'm considering this kit for my Ramcharger.

Thermoquad rules, it does have a big black plastic center section doesn't it. The Carburator Shop in Cucamungo California, pick up a high performance mopar mag, they advertise there, or see if they are on the web, I haven't tried them yet, but they get rave reviews from those who have. They will even bush the throttle shafts and replace the plastic fuel bowl section with a brand new one. Good Luck.

I'd use the thermoquad. The biggest advantage that a thermoquad has on a motorhome application is that with the plastic fuel bowl you will have much less chance of precolating fuel. The engine compartment on a motorhome is much hotter than it is on the average passenger car and anything you can do to keep the fuel cool is a good thing. With the constant and higher load, and the poorer circulation of air around the the motor, heat is a big problem.
The other advantage that the thermoquad has is the same advantage that all spread bore carbs have and that is low rpm throttle response and torque. You don't care if a Holley square bore makes more hp at 5000 rpm than the TQ because you are really never going to be buzzing the thing that high anyway. Idle to 3500 or 4000rpm is where you want your cajones
P.S. Speedmiester: The AFB carb was actually not used from factory on this new of a motorhome.

I don't have anything against the TQ,but my personal expereince is that rebuilt TQ's are not rebuilt correctly.(The kind you get from a auto parts store)To me the Holley is more user friendly.And the Holley EFI conversion would be ideal for a high heat environment that a motor home has.Without a doubt,the TQ is a great carb and performs well.Just my opinion,that's all.

You're gonna call me nuts, but I wouldn't use an aftermarket fuel injection system for a motor home. Not until I could afford a very good one. We just put a Holley Projection 2D on my fiencee's moms car and I don't really like it. Because that system doen't have an idle air control(IAC) solenoid it is almost impossible to pull away very smoothly. Don't get me wrong, the thing feels like it is really peppy and it does have some more power, but after you drive it for a while it just feels crude and jerky. Any injection system I look at in the future would have to have an IAC. Then.....HEAT SCHMEAT!!!

Very good point.I didn't know the system did not have a IAC on it.I also don't know if there 4bbl.pro-jection unit does either.I also found out that a outfit called Turbo City has complete EFI setups that are similar to the GM EFI.They have a website also.

[cudaguy]

Go to:
Demon Sizzler's Carter ThermoQuad Connection
Specializing in Rebuilding and Modifying Carter ThermoQuads at: http://home.earthlink.net/~mrburke/demonsizzler/carbs

They can rebuild or modify your TQ for what you want to do.