Hello everyone, I have been trying to figure out/decide what size carb to go with for my engine. It is just a bone stock 430 with only a different cam in it than factory. I do not know the cam specs it has been in there along time and previous owner of the motor(my dad) does not remember what the specs for it were, I don't think it was anything too wild. I have been looking at some of Holley's race brawler carbs mainly at the 750cfm and 850cfm carbs. I have also looked at getting a q-jet from quadrajet power. I'm not sure which of those to go with, I know looking through TA's catalog in the carb section they do say for a stock motor a 750 or 850 can be used. For now the motor will remain stock. I have a TA290-08H cam in store for it at a later time when I have the money to buy valve springs, roller rockers and lifters, however those all wont be put on/in the motor until after it is freshened up hopefully sometime later next year with a few other upgrades as well. The Holley carbs are currently on sale but I don't want to jump and buy one and end up going the wrong route.Any help/advice/knowledge you guys could share with me would be really appreciated.
If the engine carries the stock iron intake manifold, there is nothing better than a Quadrajet for a blend of performance and mileage. Sure, a DP Holley may gain you .05 in the 1/4 if tuned to the max, but for great mileage and response you should go with a quad. 750 is adequate for what you have, but as I've read, these big blocks like to breathe, so a 950 Holley Double Pumper may be coming down the line, regardless of what carb you choose now. That carb on the upgraded engine would be great for the strip, while the 750 Q-jet now will be good everywhere. Message Ken at "Techg8" as well. He knows how to set up and deliver an excellent q-jet
Thank you for the response I have read that about the Q-jets and have thought pretty hard about going with a Q-jet also for the fact that it's what the car came with originally and I do like the stock appearing look. Also I have been watching your build of your 430 John looking forward to seeing how the car performs now with the upgrades you have done.
Thank you, and if you still have the Q-jet that came off the car, that is the best candidate for rebuild, unless Ken or Mark can provide you one tuned for your ride. I'm excited to test it tomorrow, but it looks like it may rain all day, so we will see.
Unfortunately I don't have the original Q-jet, the motor previously had a holley carb on it with an adapter but can't remember the size since it is gone now. So either way I need to purchase a new carb.
a 750 would provide a cleaner idle and better low end response. the 850 would run better on top end. if you have some gears I might tend to go on the bigger side, if not stay a little smaller. you could make a 950 work but you will have to really work to keep the idle and low end clean, might have to go small on the squirted and really tune the bottom end. this would not be my choice for your average build 430. but I did run a 1000cfm pro systems 4150 with the top end off my 464 on a stk bottom end 430 with a decent size cam.
Ken or Mark may have the correct model number QJet in stock as a core to be rebuilt for your year motor.
Q-Jet will give you best all around performance while still providing all the CFM you need. Dont forget, there are cars out there running in the 9's on Q-Jets, it should work just fine for you.
I would have Ken or Mark build you a later 800 Q-jet. There is no better carburetor for a street car IMO. If you upgrade to an aluminum intake later, you can easily swap to a Holley DP. That is what I do, QJ on the street, DP at the track. Go to a braided fuel line between the fuel pump and carburetor and you can swap carbs in 15 minutes or less.
+1 on everything above. The Q-Jet was tested for thousands of hours by GM/Buick engineers, and a correct build with the modern upgrades will give you the best bang for the buck. Holleys are good for blowing fist-sized holes in your mufflers. My friend's 64-1/2 Mustang met that fate once a Holley 650 DP got bolted onto the torker.
I'm curious why use a Q-Jet on stock iron heads and Holly on aluminum heads? If one was to upgrade to the B4B or Edelbrock Performer would the Q-Jet not work well?
in theory any carb the correct size can/would work. some are just more user friendly to adjust. some have enough adjustments to get ppl in trouble
I use both, QJ on the street, Holley on the track. What makes you think a QJ won't work with aluminum heads?
Were did you come up with heads????? The stock cast intake has a hot air choke for the divorced Qjet.. The aluminum intakes doesn't have the same style choke system.. Although the are ways to get a choke to work...http://www.taperformance.com/proddetail.asp?prod=TA_1241 .........http://www.everyday-performance.com/electric_choke.htm
Thank you everyone for the responses. It has been very helpful and helped me see the benefits on each side. I haven't fully decided which way I am going to go just yet but I will say I do like Larry's setup and just switching between either one when needed.
Oh sorry I meant intake. From this quote it seemed like an upgrade to aluminum intake would be better with a Holley. But after reading more maybe it was more track vs. street tuning not necessarily the fit on an intake. My mistake.
My point is that most if not all aluminum intakes have both bolt patterns for spread bore and square bore. The stock iron intake is only spread bore, so to run a Holley, you need an adapter. In addition, the spread bore opening will accept both the Q-jet and Holley. The Holley opening will need to be opened up to accept a Q-jet. So if you do buy an aluminum intake, get one with the spread bore opening, not the Holley opening.
