SMI stands for Sean Murphy Inductions, and he specializes in rebuilding Q-Jets the way America intended them to be built:-) I'm only kidding, but apparently he and his technicians can do amazing things with an amazing/tempermental carb.

I'm not selling them, despite what my introductory statement may suggest. I have only read about these carbs. Does anyone on this forum have an SMI Q-Jet Carburetor?

My application is a 455, so it would be the big 800cfm carb. Anyone have one of these?

 

Never heard of these guys, but there are several top notch Qjet guys around yet. I have never had a need to use thier services, as I buld my own, and have a few tricks up my own sleeve,lol.
The high CFM Qjets pop up on ebay pretty regularly, just verify the carb number before bidding, and ask for close pics to see if the carb has been exposed to moisture, or stored properly. I have seen a few to far gone due to moisture to even be a viable core, had to just save them for parts.
Jeff

 

Temperamental? No one, with a basic knowledge of carburetors, will agree.

At your power level, 750 CFM is more than your 455 can use.

Norm

 

Absolutely right, the Rochester is the most forgiving carb, and least tempermental.
That's why it remained the carb of choice for all gm divisions from the 60's to the age of fuel injection. When it works,, don't fix it.
I also agree that for non-race use, it's not a big priority to find the big Qjet,, if a good deal can be had, it isn't a bad thing. Myself, I rather like the 78-80 car, and 78-85 truck Q jets with electric choke, and adustable PTA for non-race use.
Jeff

 

I Have A 1970 Cutlass 350 cid I Got One Of His Q-Jets Carbs, My Car Ran Like Crap I Took It Back And Got A Refund.I Wound Up Rebilding My Own
And I Changed The Back Rods And Change The Primary Vacuum Spring. It
Runs Great. So No More SMI For Me.

 

I would have to agree with Raymond. stay away from SMI. I bought a Stage 2, 800 cfm Q-jet from SMI carburetors...it was a total turd. You have to give him all sorts of information about your build, and it leads you to believe the thing is going to work like nothing you have seen before. The one he did for me never did work and Sean was no help what so ever online or even over the phone. The choke didn't work right, and no matter how many adjustments I made to the dam thing it had quadra-bog that wouldn't go away. I tried for a month to get it straightened out, it just wouldn't perform anywhere near as well as the Holley 770 Street Avenger it was supposed to replace.

I should of sent it back for a refund, but I was sick of dealing with them and just sold it on ebay for half of what I paid for it. I am much happier with the Holley, and besides. Q-jets are FUGLY!

 

I have one on a 400 pontiac took some time to set up ( I had never worked on a Q jet ) The bog was a secondary door adjustment and just getting it set right. works good for me . I was sent the long filter housing he sent me the short out right away and worked with me on the phone
in trying to set up .. give clif ruggles a look too not cheap but alot of fast pontiac guys use him.

 

I'm running an 800 cfm, that Dean Oliver modded for me. You can find him here http://www.retunedmusic.com/deano/
Good guy, and he provides great advice after the sale.

 

www.sparkyscarbs.com

i thought i'd throw-in a shameless plug.


bill

 

I've rebuilt 3 Q jets. Two from a 71 and a 72 Caddy and an electronic Q jet from a 88 Caprice. I Basically disassembled them cleaned, and put them back together with new gaskets and floats. I didn’t mess with any factory settings or choke/throttle rods. Some of the brass feeder tubes for particular circuits had to be pressed back in place. The Electronic carb required resetting the solenoid height. None had worn bushings. All three worked excellent after a rebuild and all had excellent cold weather drivability. If you can build a model you can rebuild a carb provided it’s a good core.