Advice for setting up Q-Jet on new engine

[smbrouss70]

Hello,

I have just built a new engine for my 1970 2wd Blazer to replace the tired original 350.  I am asking for a little advice as to where I should start on my carburetor tuning since I have no idea which jets, metering rods, orifice tubes, etc. that I should try first.  I have bought and read Cliff’s book and it is slowly making sense to me, but I’m a hands-on type of person, so it will probably make more sense once I start tearing into the carburetor.  The Q-jet that came on the Blazer (not the original one) is a 7042208, but I replaced it with a rebuilt Q-jet that I got from a swap meet which is a 7042211.  Both were good matches on top of the stock engine, the original was only replaced because it was worn out but should still be a rebuildable core. 

Is either the 7042208 or the 7042211 a better core for what I am doing?  I just want a strong running cruiser, no racing (besides a little fun with friends).

I have listed the Vehicle and Engine Specs below so that you know what I am working with.  If you need any more information on anything just ask, and I will get it for you.

Vehicle
•   1970 Chevrolet Blazer 2wd (approx.  4,000+ lbs. with top on)
•   3.07 posi rear gear (changing to 3.42 or 3.73 soon) with 28” tall rear tires
•   700-r4 transmission with 2,400 RPM stall lock-up converter
Engine
•   350 SBC with standard bore
•   Approx.  9.75:1 CR
•   TrickFlow Super 23 Angled plug aluminum heads, 62 cc, 195 cc intake runners, 2.02 - 1.60 valves
•   Lunati Voodoo 20120711 Hyd. Roller cam 219 In./227 Ex. Duration @ .050, .515 In./.530 Ex. Lift
•   Edelbrock Performer RPM Q-Jet Intake # 7104
•   Garage bench estimated just over 400 HP

[77cruiser]

I'd use the later one late 70's to mid 80's except electronic ones. But that's me.

[Cliff Ruggles]

Those carburetors are pretty much the same thing but set-up slightly different as they are not the same application.

Being "rebuilt" doesn't really mean much, most of the rebuilt carbs we get in here have issues.  Did you attempt to use the carburetor on your engine?  If so, did it work well in all areas, or need some help?.....Cliff

[smbrouss70]

The "rebuilt" carburetor was on the original engine for over a year and performed well for being on a weak (probably 200 HP or less) engine.  I did put it on the new engine and it seemed very sluggish off the line for the time that I was able to drive it.  My transmission cooler in the radiator started leaking and got water in my transmission, so I am in the process of fixing that before I can try tuning on it more.

Before I bought the swap meet carb, I did buy one of your HP Carb kits & your book to fix the original, but found the swap meet carb before I got around to rebuilding it.  The kit is still in the bag that it came in, I am thinking of rebuilding the original with that kit, but I am unsure of where I should start on the jets, rods, etc. for my combination.

I also realized that I didn't list the LSA of the camshaft in my earlier post, it is 112° LSA.

[Cliff Ruggles]

There are several ways to tune the carb that you intend to rebuild for that application. 

First remove the APT screw from the baseplate.  Use plenty of penetrating oil and a little heat from a propane torch from the underside.  Once it is out call the shop and we can recommend tuning parts with an external APT screw......Cliff