Author Topic: Gm vortec crate motor carb?  (Read 4030 times)

Offline benbuff

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Gm vortec crate motor carb?
« on: July 25, 2017, 02:22:32 PM »
Will a carb work on a 99 gm 350 vortec crate engine?  I know they don't have a heat riser and wanted to know if I could use an edelbrockvortec qjet intake if I could run a qjet on it?

Offline 77cruiser

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Re: Gm vortec crate motor carb?
« Reply #1 on: July 25, 2017, 05:12:34 PM »
How cold will it be driven in?
Jim

Offline benbuff

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Re: Gm vortec crate motor carb?
« Reply #2 on: July 26, 2017, 12:16:47 PM »
I live in Idaho so very cold.

Offline 77cruiser

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Re: Gm vortec crate motor carb?
« Reply #3 on: July 28, 2017, 10:29:40 AM »
Probably not as cold as we are but you still need some carb heat below freezing. Some ducting from the exhaust manifold or headers like the factory used.
Jim

Offline Cliff Ruggles

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Re: Gm vortec crate motor carb?
« Reply #4 on: July 29, 2017, 03:43:00 AM »
All of the factory intakes for Q-jets used a heat cross-over from what I've seen.  This was done to get the intake heated up quickly and improve cold weather operation. 

You can still use a Q-jet on the Vortec engine even though it doesn't have any heat passages in the intake manifold.  It will be fine most of the year but expect some possible "icing" in really cold weather and it may not run well until the intake heat soaks some in the cold Winter months. 

It will be fine most of the time otherwise when outside temperatures are above freezing.  I haven't had a heat crossover on my engine for decades since I use aftermarket aluminum heads that don't use one.  I've never ran into any issues, and even started the car last Winter when it was 25 degrees below zero outside.  It did take a LONG time in that scenario before the intake heated up enough so the engine would idle, but fine after it heat soaked a bit.......Cliff

Offline benbuff

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Re: Gm vortec crate motor carb?
« Reply #5 on: July 29, 2017, 05:26:00 AM »
Thanks for the info guys.

Offline Cliff Ruggles

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Re: Gm vortec crate motor carb?
« Reply #6 on: August 02, 2017, 04:22:49 AM »
If you do some Internet research on using or not using a heated intake you'll quickly find a LOT of varying opinions on the subject much like anything else related to this hobby.

I highly recommend using the heat crossover in the intake if it is in place.  There are really no negatives from doing so, unless possibly if you lived on the equator and it never got below 80 degrees outside. 

A working crossover in the intake provides many advantages, and blocking one off or not using it just delays heating up the intake as it will heat soak eventually anyhow. 

The intake needs to be hot to keep fuel from "globbing" up on the walls and requiring a much richer mixture to make the engine happy with a wet flow system. 

Folks claim "vapor lock" and other problems with having one, but the carburetor, especially a Q-jet has high velocity air coming down thru it for cooling, and most factory gaskets between the carb and intake act as insulators to keep the fuel from boiling in the bowl.

For operation in sub-freezing temperatures the crossover really helps to prevent freezing/icing and makes for much greater efficiency and much faster warm-ups.......Cliff