Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

qjet 17053230 set up for fe 390

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74 Powerwagon:
I have a 17053230 quadrajet that I want to set up for a fe 390 engine in a F250 highboy. The engine is .060 over with an rv cam and D2TE heads. I got the carb with a dodge 318 and I don't know what it was originally from. I have measured the orifices and they look about like this: idle tube .053, idle down channel .053, upper idle air bleed .052, lower idle air bleed .072, body main air bleed .052, air horn main air bleed .072, idle bypass air .045. I have main jets in .070, .072, and .073, and rods in 51m, 52m, 53m , and 50p. I have secondary hangers h,m,n,p,r,and s and secondary rods DA, CH, DR, and DP. I will get a set of main rods and jets from Cliff as he recommends. Any advice on carb set up would be appreciated, I think I need to open up the upper idle air bleed and main air bleed in the body. I live at 9k in Colorado and have and read Cliff's book. Thanks for any advice, Kent

Cliff Ruggles:
Check the carb number again, it's probably 17058230 not 17053230.

Don't touch any of the airbleeds.  That carb is for a big Caddy engine and the 390 will like the richer calibration. 

When you get time call the shop and I'll put together a custom rebuild kit with tuning parts.  The big 390 will need the high flow N/S assembly and HP accl pump.  Those are great engines, very strong runners and very strong internals.......Cliff

74 Powerwagon:
Thanks for your input and encouragement Cliff. I called the shop and will get your direct suggestions and a kit. I have been running a qjet from a chevy 305 on my 318 motor in my 74 W100 PU. I got primary rods and jets from you and followed guidelines from your book to tweak that carb a bit. Runs great, smooth power delivery so I'm excited to see how it runs when I get a set of swirl port heads and a 340 cam put on it. I love the qjet, the detractors are so wrong, no harder to set up or rebuild than any other carb and more adjustable. Sending the 390 block out for some cleanup and then I'll reassemble.

Cliff Ruggles:
Cool, great discussion yesterday, let us know what you end up doing for cam/compression and how it works out.

I did forget to mention that if you are spending all your time with it at 9000' or so you can get away with more compression and smaller camshaft as it's going to act a little lower for compression that it would at lower elevations.

I still think the XE256 cam on a 110LSA is a poor choice for a 390 engine in any configuration.  Those engines were not all that efficient compared to other Ford offerings like the little 302, for example.  With the big layout and long intake runners I'd be looking at larger cams on wider LSA's with about 10 degrees more exhaust than intake duration to help it out some.

Here is a really good cam for a 390 FE engine for a truck/towing application:

https://www.summitracing.com/parts/mel-cl-mtf-4/overview/make/ford

It sports more seat timing than the little 256XE and wider LSA.  This means it's easier on the valve train and would work fine with stock spring pressures as well.

Here's another offering I found that would be excellent for a truck engine with higher compression:

https://www.summitracing.com/parts/hrs-cl257711-15/overview/make/ford

......Cliff

74 Powerwagon:
Hi, Ive been working a lot and hadn't gotten back to the forum. Thank you for the cam recommendations. One thing I hadn't mentioned is that the block has been decked .010 previously, I don't think that effects compression numbers that much(?), I also have the TRW L2291 pistons in the engine. I will ask the machine shop about the piston to deck numbers and resulting compression. I have both D2TE and C4AE heads, I think they have similar size combustion chambers and I will go with the smaller runner D2 heads that better match my streetmaster intake. I'm favoring the Howards cam, what effect does that really wide 115 LSA have.

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