SleeperScamp
Well-Known Member
I have the 850 thermoquad off my 78 Lil Red Express. Is this carb any better than the Edlbrock 750 (1411) that I have on my Duster now? Any gains in performance? Thanks
Carb Choice??
- Thread starter SleeperScamp
- Start date
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lil red
Well-Known Member
dont know if this helps but I once put a 625 carter on my LRT back about 15 years ago .... jetted it, but it never had that "seat of the pants feel" of the TQ large spreadbore secondaries opening up ...plus it was harder on gas so I switched back to the TQ
When I rebuilt the motor last year I was going to switch to a 750 edy but guys on here convinced me to keep the TQ .... dont know if the TQ makes more power , but it sure feels like it does
Had mine rebuilt by Demonsizzler, he claims they make good power and are easily tuned
Jimmy
P.S. you wanna sell it if your not using it?
When I rebuilt the motor last year I was going to switch to a 750 edy but guys on here convinced me to keep the TQ .... dont know if the TQ makes more power , but it sure feels like it does
Had mine rebuilt by Demonsizzler, he claims they make good power and are easily tuned
Jimmy
P.S. you wanna sell it if your not using it?
Salty Dog
Well-Known Member
For the most part, the TQ is hard to beat. The reason is the primary side is small and sensitive to it's position. The engine reacts very well with the high velocity air speeds that run through the primary side.
The secondary side is spring loaded and tuneable.
The draw back of the squarebore carb is the primary side are equal or near equal in size so there isnt a powerful primary reaction unless it is properly sized and if it isn't, it feels soggy. When the secondary side kicks in, it will feel like a turd or nothing is happening.
For street strip and drivers (Stock or mildly modified) the TQ is my weapon of choice.
Full track runner, it is a Holley. But the Holley I'm useing is not a stock carb! Double pumper, 4 corner idle, adjustable air bleeds. A TQ doesn't have that. (Or really even need it.)
The secondary side is spring loaded and tuneable.
The draw back of the squarebore carb is the primary side are equal or near equal in size so there isnt a powerful primary reaction unless it is properly sized and if it isn't, it feels soggy. When the secondary side kicks in, it will feel like a turd or nothing is happening.
For street strip and drivers (Stock or mildly modified) the TQ is my weapon of choice.
Full track runner, it is a Holley. But the Holley I'm useing is not a stock carb! Double pumper, 4 corner idle, adjustable air bleeds. A TQ doesn't have that. (Or really even need it.)
MopaR&D
Nerd Member
I don't mean to hijack but would using a spacer to run a TQ on a square-bore manifold (Eddy RPM) be less efficient than running a good street square-bore like an AVS?
Salty Dog
Well-Known Member
More so a space problem. Carb height is an issue. Not a fan of that spacer.
MopaR&D
Nerd Member
Of course, I meant space limitations aside. I think a TQ with a spacer would fit under my hood if I got a drop-base air cleaner; right now my factory dual-snorkel 4-bbl. air cleaner fits nicely on top of an AFB carb, 1/4" spacer and RPM Air-Gap.
...............A good working TQ is hard to beat for the street......kim........
BillGrissom
Well-Known Member
A poperly operating TQ should be more efficient, if you mean gas mileage, assuming you stay off the secondaries except when really needed. The problem is that I read of many TQ problems from warped bodies, lack of spare parts, etc.
Adding a spacer would probably increase mileage, from more time to vaporize droplets before splitting to the runners, so better fuel distribution. A longer runner path increases mid-range torque (slant six, Magnum, most modern engine intakes). Indeed, racers purposely use spacers or tall intakes.
lil red
Well-Known Member
I run a 3/4" adapter/spacer for my TQ on an LD340 intake. I also use my factory dual snorkel air cleaner and use a 2" spacer btween the carb and air cleaner. TQ's dont like dropped base air cleaners - the lid should be up off the carb to improve air flow - not so irregular
Salty Dog
Well-Known Member
Thank you!
lil red, do you know that you can modify the carb pad on the LD-340 to fit a TQ?
Great mention on the air cleaner base plate. I have noted just that. A drop base is difficult to find for a TQ. The top of the fuel bowl's are tall and finding a drop base plate to fit is a pain.
Also, the limitation above the carb hamppers the carb at wide open throttle. Through a lot of tried out air cleaner units, a carb just simply needs space above it to operate correctly, freely and at it's best potential.
lil red
Well-Known Member
does the carb spacer improve flow - or should i just machine the intake to accept the carb. Someone mentioned once to add the spacer so I made it years ago
just wondering - thanks
Salty Dog
Well-Known Member
This question I can not answer. I really do not know. I supose the wrong spacer would, but I really do not see it with the typical TQ to squarebore adapter.
I have machined the carb pad on the intake on a LD-340 in the past. It worked just fine. Also, (Did I mention this earlier? non the less...) Use a thick OE style gasket to help keep heat away from the carb.
MoPar used to offer 1/4 thick plastic spacers for tuning. Sealedby the thin paper gaskets. If you can, raise the carb so the butterlies are at least even with the carb pad's top of the intake manifold. IIRC, the secondaries are approx. 1/2 inch and as such, the carb should be raised that high.
Do not mill the center divider unless your going to use a preety stout cam. The old MP books suggest's a cam of .550 lift. In the old days, when this was writen, that cam of .550 lift (Or greater) would be a Purple 296 solid. IIRC, this is something like a duration @ .050 of 250*'s.
That is a bit of cam for the street.
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