Roch quad carb useage??
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Re: quad carb useage??
Man, from the looks of this thread's title, I thought you might of been talking about using 4 carbs on one motor! [email protected]!
Man, from the looks of this thread's title, I thought you might of been talking about using 4 carbs on one motor! [email protected]!
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Re: quad carb useage??
Put it on and see.
Generally a carb for a smaller motor will be lean at idle since it feeds gas based on vacuum but the larger motor is drawing more air at any given vacuum; and it will be rich at cruising and other higher-speed conditions.
But it might be just fine.
Put it on and see.
Generally a carb for a smaller motor will be lean at idle since it feeds gas based on vacuum but the larger motor is drawing more air at any given vacuum; and it will be rich at cruising and other higher-speed conditions.
But it might be just fine.
Re: quad carb useage??
Just came back to check for responces & realized the same thing :clonk:
The late 60's-early 70's q-jet carb its self will work fine for your mild 454 but it will likely be a little lean if it was in fact still setup for a factory stock 300 hp sbc.
For an initial setup i would start with 45b rods with 72-maybe 73(if headers/mild perf cam) prim jets,AX or BG secondary rods,with a larger .0135" needle & seat for enhanced fuel flow into bowl to quicker refill the fuel bowl under full load & top end situations when getting into it.
You can get the larger needle & seat from " Jet Perf " ,the secondary metering rods,prim jets, are still avail from GM(the 45b prim rods are not aval fro gm anymore). But you can also get all these q-jet parts including a kit/gaskets at a couple other places on the intranet.
Let me know if your going to rbld your q-jet your self and i will get the site for your for parts.
Also,if you want you could send the carb to "Sean Murphy Induction" (see his website) he is great with q-jets and can easily setup your carb secifically for your motor setup/cam etc.
Scott
For an initial setup i would start with 45b rods with 72-maybe 73(if headers/mild perf cam) prim jets,AX or BG secondary rods,with a larger .0135" needle & seat for enhanced fuel flow into bowl to quicker refill the fuel bowl under full load & top end situations when getting into it.
You can get the larger needle & seat from " Jet Perf " ,the secondary metering rods,prim jets, are still avail from GM(the 45b prim rods are not aval fro gm anymore). But you can also get all these q-jet parts including a kit/gaskets at a couple other places on the intranet.
Let me know if your going to rbld your q-jet your self and i will get the site for your for parts.
Also,if you want you could send the carb to "Sean Murphy Induction" (see his website) he is great with q-jets and can easily setup your carb secifically for your motor setup/cam etc.
Scott
Thanks Scott, I have re-ringed & bearinged the motor over the winter & as soon as snow is gone I can get out the car & begin installation :hurray:
I will do a first fire-up & break-in with the original truck quad because I know it works & idles flawlessly. Then I will try & get this 1970 quad set up & running properly for this motor. I understand the 86 truck carb is not good for any kind of performance applications?
I will do a first fire-up & break-in with the original truck quad because I know it works & idles flawlessly. Then I will try & get this 1970 quad set up & running properly for this motor. I understand the 86 truck carb is not good for any kind of performance applications?
>>works & idles flawlessly.
>>86 truck carb is not good for any kind of performance applications?
I've built a few Q.s over the years and I don't see why your 86 carb wouldn't work OK. It might need a jet and rod update and a couple other tweaks but it's a good carb fundamentally. Probably an 800CFM version to boot.
>>86 truck carb is not good for any kind of performance applications?
I've built a few Q.s over the years and I don't see why your 86 carb wouldn't work OK. It might need a jet and rod update and a couple other tweaks but it's a good carb fundamentally. Probably an 800CFM version to boot.
I know some 86 q-jets has minimal electronic controls in cars and thats why some pelpe would not use them but i dont know if they had telectronic control on the trucks in 86.
If you have the older late 60's- through 1973 version q-jet just go with that IMHO.
scott
If you have the older late 60's- through 1973 version q-jet just go with that IMHO.
scott
I was under the understanding these 170s were harder to tune or ??something that made them not as good as the earlier ones?
There were no electronics on this carb, except choke & it's got same size primarys as most quads, so I don't think it's a 800cfm version.
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