2bbl vs Thermoquad

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racingsnake440

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Which do you think would get better economy on a stock 318? I think in normal driving there would be very little difference. Anyone got any practical experience? The thermoquad would be fitted on a small port Weiand dual plane intake.
 
Practicle experience...
Awfully hard to keep the foot out of those other 2 barrels, for most folks anyway.
 
If driven without opening the secondaries, the T-quad would probably give better economy. The primary blades are smaller on it than on the 2 bbl.
 
What kind of driving does your "normal" routine consist of? Do you sometimes find yourself pedal to the metal with the 2-bbl and need more? As mentioned above, can you keep your foot out of the secondaries when not needed? I think it really depends on what kind of driving you do and how much self-control you have. BTW: Is that Weiand set up for a spreadbore or is there an adaptor being used? Let us know what you decide.
 
I did this in 1974 with a 340 TQ intake on a 318 and disconnected the back two barrels. ran just fine, and better fuel econ.This was in Denver,when we went to the track we uncorked the headers and hooked the secondaries back up.The TQ worked great in the thin air.
 
The Weiand's set up for a spreadbore. Think I'm going to go ahead and change it because the 2bbl's got a bad flat spot and I can't be bothered to work on it. I can keep my foot out of it most of the time and if the economy is the same or better doing that then I don't mind paying a bit more when I do get into it - not that a stock 318 is going to be quick anyway...
 
in theory the theromoquad should get better mileage with those tiny primaries.. but reality show its really hard to keep you foot out of it with a 4bbl..lol
 
The thermoquad does have small primaries but I'm not so sure their actually smaller than the tiny 2 barrel used on 318's. If it was the bigger 2 barrel like used on a 360 I'd say go for the thermoquad but keep your foot out of it but I'd say it could go either way.

BTW: Are you sure your just looking for mileage gain or need an excuse to put a 4 barrel on it?:burnout: Reason I ask is you say you don't have time to work on the 2 barrel but you have time to swap the intake and carb. I can easily rebuild 3 or 4 2 barrels in the time it takes to do an intake/carb swap.
 
I'm not really looking for a mileage gain just didn't want to put the 4bbl on and find the mileage is much worse. It's my daily driver and mileage is more important than performance at the moment. On the other hand I think 2bbls are junk and don't want to waste any time working on it so when I getchance I'll swap it out.
 
Depends on what size TQ you put on there. The 800 has the smaller primaries. A friend of mine is whacking down 29.5MPG in a '68 Cuda coupe with a 318 with a 273 2bbl cam, lots of compression, 2.76 gears. BTW he is running a 850 TQ.
 
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