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I have a 79 pace arrow with a 440 dodge. We wanted to try to get more power and perhaps better gas mileage from the 440. We put in an eddlebrock performer intake manifold, replaced the stock exhaust manifolds with headman headers, replaced the dual exhaust with a single 3 1/2 inch pipe with dyno flo muffler and Y connector. We also removed the thermoquad carb and replaced it with a quadrajet carb from a 78 cadie with an engine that was 20-30 cu in smaller than the 440. It seem to run fine and much smoother than with the thermoquad. I still don't run up the hills as fast as I would like, but it is much better. The question I have is that I was talking to a mechanic friend of mine who told me that I run a chance of burning up the engine with the quadrajet because a passenger car carb is different from a motorhome, 1 1/2 ton truck or marine carb. He said something about the bore of the jets and the cam won't match. He recomended a Holley spread bore instead. So my questions is am I ok with the quardrajet or do I need to Increase the bore of the jets or change to a Holley or a marine carb? How would I know if this carb is OK or if I need to change something? I know that I might get a little more power with the Holley but I think that I will get better gas mileage with the quadrajet. Didn't Dodge go with a quadrajet in 1985 anyway on the 440?
Any other suggestions for more power, besides getting another motorhome?
As we used to say, a carb has no idea of the size of the engine it is bolted to. The Q-jet you have is calibrated to mix a certain ratio of gasoline to a volume of air, both by weight. Coming off of a '79 engine, it is most likely a bit on the lean side all around, but that is easily taken care of by a good carb shop. IMHO, the Q-jet is a very good carb and should give you no trouble. Engine power is a trade off with fuel economy, unless you live in the Rocky Mountains, you are going to be driving mostly on flat land where you don't need a huge amount of horse power. The 440-3 is a very good torque engine and is made for pulling, which it does very well. The last year of production for the 440 engine was 1979.
I was just wondering if you still have the thermoquad and if you want to get rid of it? I have a 1981 440 and someone at one time put on a holley and I would like to go back to the original carb.
like he said a Q-j from 1979 is probably set up lean,
primary and secondary metering rods come in many forms''
the secondary air door is a preminum adjustmenton the Q-j adjust it no more then an 1/8 of a turn at a time, watch out its spring loaded. if you dont have a srewdrive on it and loosent the alen bolt, the intial adjustment is, just gone. twang. lol
the bigest problem with the Q'j is the lack of the float bowl's ability to stay full enough on a healthy hill.
thats why on a MH I would set the float kinda high, and hope for the best..
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