Well guys my 4bbl fantasy land is over. After having so much trouble with these various quadrajet carbs I have decided to downgrade to MC 2bbl from a big motor(probably 390 FE). My 300 has a lot of miles on it, and even though it runs good it is getting tired, and of the cylinders is a little weak. I have decided that the right quadrajet would be awesome if tuned correctly on a fresh, or built 300, but not the best for a tired old stock 300.

I don't have a small 4bbl carb, I sure can't find one in my area on craigslist, and I really can't afford much right now. So I guess I am going with a MC 2bbl, because they are cheap, and awesome, hopefully it won't have any bog like the Q-Jet so it will seem smoother, and run better.

One of these days when(IF!) the truck is fixed up nice I might spend the money for a rebuild, and find myself a real good Q-Jet with a good choke on it, but until then I hope I am not too disapointed with a 2100 or 2150.

 

I put an Edelbrock #1403 with electric choke on my 300 with a offenhauser dual plane intake, it's a 500 cfm carb and I have a fresh rebuild on the 300 six but I have no issue at all, I have no bog problems and other than the exhaust smelling a little rich, it starts, Idles and runs excellent. I would highly recommend the Edelbrock #1403 carb.

 

I think a 500 Edelbrock wouldn't be to bad, but I can't be sure of that, and I can't find them cheap locally(craigslist). The only thing that is selling cheap around here are 600-1000 CFM carbs that will be worse than the Q-Jet. If my motor was more fresh I think a Q-Jet would be fine, but my motor has a lot of miles it has probably had a hard life(goose neck was in the bed at one time), and it just really shouldn't have that much carb at this point(without a rebuild). That is why I am going with the 2bbl(carb only I will still use the 4bbl intake), because I know that it will run decent(maybe better than the Q-Jet), and be plenty reliable for my old war dog.

 

FWIW, the 500 and 600 Edelbrock carbs are the same other than the jets/rods and maybe the pump squirter. Go download the Edlebrock Performer carb tuning manual and check the specs - same venturi sizes.

That said, unless the engine is modded I think most 4-barrels run rich for a 300. I'm actually rebuilding a 2100 carb now to replace the Edelbrock 500 on my Offy C manifold until I can have a new, pepped up engine built.

 

I'm thinking the same thing Baron. I will go back to a 4bbl assuming I heat it up a little more during a rebuild.

 

Hey dwrestle

I had a Q-jet on my truck when I first put my offy dp intake and efi manifiolds on and did the duraspark converstion and I could never get the thing to run right!! I messed around with it for weeks! It was a new factory reman Q-jet. Would not for the life of me run right. Would Idle good. Horrible bogs. Go to stop and it would almost die and then surge and it was a pain. Bought a Edelbrock 1403 put it on ran like a charm! Been running it for almost a year now and haven't done anything beside mess with the rods and jets and getting around 14city and 16-17 highway. Compared to 8-9 all around when I had the 1bbl and Q-jet. Im not knocking the Q-jet but the Eldelbrock 1403 500cfm and 1405 600cfm are basically the same just different rods/jets spring/squirter setups I believe. If you can find one of those and put it on I think you would be more than happy with it compared to the Q-jet.

 

I don't have any experience with running an edelbrock on a 300 I6 (yet), but I do have a 1405 600CFM on one of my RX7's. That carb, straight outta the box, works perfectly on the 1.3L (80cid) rotary in all but 1 minor way. Since it mounts with a 90* rotation (like the I6 with the offy DP) it suffers from a stumble exiting a high G-load turn. Otherwise, it totally mops the floor with the holley 600 I have also tried on the same engine. "Normal" driving/cornering does not have this stumble issue, and the stumble is only during hard right hand corners. I have done everything edelbrock's tech help has suggested, and will be trying it out this weekend (sanctioned motorsport event). If the stumble returns, the holley will go on for now. I plan to swap to a holley 650DP regardless, in the near future.
The overall plan, is to install an offy DP on my 300, and top it with the 1405 that I already own. The 1405 has only remained on the rotary due to not having yet aquired/made all the pieces (fuel line and throttle cable bracket) needed to install the 650DP sitting on the shelf....
I doubt the truck is even capable of reaching the G-load cornering that appears to be the wrinkle in the edelbrock's otherwise shiny armor.....