thinking about a carburetor

[bake315]

While I've been going through the process on my 454 rebuild, here...

http://forum.73-87chevytrucks.com/smforum/index.php?topic=14348.0

I've started thinking about what I want in terms of carburetion.  I think I may have found one that might work...

http://www.smicarburetor.com/products/sfID1/28/sfID2/9/sfID3/32/productID/837

Based on their description of application, the only thing that doesn't match up with what I'm doing is that my compression ratio is going to be closer to 10:1.


One of the other things I have considered is finding a Q-jet that would have originally come on a truck of this vintage ('73) and rebuilding it.  There are a whole bunch for sale out there, but how do you determine cfm's from one Q-jet to the next?  I know about how you can tell what the carb belongs on, but I can't figure out the cfm's.

[bgctrading]

Take a look at Holley Street Avengers.

[mountaindrew]

Everything I've read about the Quadrajet leads me to believe there are none less than 750cfm, which is plenty for your low rpm duty big block.  I really like my Qjet, properly tuned and they're hard to beat.  I must have missed your original thread about your 454 rebuild but it looks like winner.  Post any updates in that thread please!

[Captkaos]

There is only 2 versions on Qjets, which are 750 and 800.  The 800's were used on BBC applications , NON Chevy.  I would just get a stock one and rebuilt it and save about $300.  I just got rid of one on Craigslist for $40.

[Blue 82]

I bought a stage II SMI Q-Jet for my 9.25:1 small block about two years ago
I picked up 2 mpg towing my boat till Florida mandated ethanol in the fuel
Then fuel milage went back to 10 MPG
Even when the weather dipped down in the 30's for a week down here, it started just fine
I have the intake manifold heat crossovers blocked off (I live in South Florida)
So I had to let the engine warm up for 10 minutes before driving anywhere when it was that cold
(start truck, turn on heater, go back in house, drink an extra cup of coffee. I suppose this is the standard procedure for Yankees)

I have not had a bit of trouble with it
It runs much better than the 400,000 mile Q-jet I had on the truck (rebuilt 3 or 4 times)

Together with a good ignition, that's dialed in for your combo
$359 is a small price to pay for a good running carb.
All I had to do was set the idle speed, and the mixture screws
For an extra $25 he included the Air Conditioning Idle Solenoid with the screws. (very important in S. Florida)....

For an every day street truck a Q-Jet is hard to beat.
I'm more than happy with mine

I'm curious, as to why you are running so much compression
I think your combo would be happier with a Pump Gas friendly 9:1 to 9.5:1 compression, especially with the mild cam you are considering.

[bake315]

There is only 2 versions on Qjets, which are 750 and 800.  The 800's were used on BBC applications , NON Chevy.  I would just get a stock one and rebuilt it and save about $300.  I just got rid of one on Craigslist for $40.

I just went and picked one up locally for $10.  It's number is 7027240, which I think means it was manufactured in 1967 and came on a Buick. It's also in pretty rough shape... rust on the linkages and mud daubers in most of the holes.  Don't know if I'll use it, but might be good for use as a reference.