So i think ill settle with the 625. Why does everyine love the thermoquad?
Because the small primaries afford excellent throttle response, good velocity for excellent fuel atomization and the potentail of better fuel mileage.
The secondary side has tunable spring loaded air door that opens up to massive 2.25 X 2 throttle plates.
The carb is a 3 part sandwich with the phenolic resin center keeping fuel cooler by approx. 20*'s.
The tuning rods are hard to come by. But they are a three step rod. It can be confusing to tune with them. But it can offer a good fuel curve. Generally speaking, there a cheap carb. With flow rates of 800 & 850 CFM, you can use them on a wide verity of engine sizes and combinations.
The TQ is best used as a street or street strip carb because it is very flexable and forgiving. To use one as a race carb would require some good knowledge of a carb and the TQ itself.
Draw backs in reply to the next quote....
They don't... we called them thermo-BOGS back in the day use to throw them in the garbage...
Yes! Very popular carb to miss treated and abused. Once they went out of wack, work out and became highly miss adjusted, no one wanted to learn to fix and tune them. The heat got to many of them and crack the middle section. Then after cool down and many heating and cooling cycles, the aluminum top and or bottom warp. Throttle shafts hollow out, linkages bend. It becomes a mess and nearly impossible to fix on the home front.
When the carb was largely in use, under hood temps with tons of emissions devices furtherly hampered the carbs ability as a performer. The TQ was not alone in these troubled years.
Heat was that carbs biggest enemy and problem.
The current problems of the TQ start with getting a good core. Then a proper rebuild. Followed by proper parts. Many people forget or do not realize the gasket needed under it needs to be thick! Not the normal paper thin gasket.
Next would be the lack of electric choke models. There are hard to come by generally speaking and non existing in the larger 850 version. You have to ether remove the choke flap or cobble a cable for it. Also rods and jets are hard to find and pricey when found.
The big inch Buick guys love the thermoquad also.
I don't know any big inch Buick guys. Rare to see one period.
