Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

Qjet building

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FORREST MILLER:
First Off I'd like to thank you for helping out all the DIY'ers out there  by doing the book. I've spent the last month reading, and rereading, and I think I'm understanding the concept Of the Qjet....what a great carb.  Once again thank you ;D

I'm doing a carb for my corvette, and as suggested in the book I went and measured everything and this is what I found:

Idle tube.................................  .031"
Idle down channel ................... .057"
Upper idle air bleed.................. .070"
Lower Idle air bleed................. .078"
Idle bypass air......................... .069"
Mixture screw holes................  .096" (I  Did this)
Holes in throttle plates...........   None
Main air bleeds ......................  .125"
Secondary POE ...................... .055"
Secondary tube restriction...... .025"
Accelerator pump squirters....  .078"

The only thing that alarms me here  the size of the Accelerator pump Squirters. They dont look like they have been drilled out, but this carb has been rebuilt by one of the commercial rebuilders at one point in time. Are they too big?

I plan on redoing the carb according to "Recipe#2" Using 77 main jets and 50 rods.   Will I have any problems with those large squirters?   And do you see any problems using "recipe 2" with my engine combo?

SBC   406
vortec heads
performer intake
10:1 compression
comp hyd roller cam xr276hr
Intake    224@50  .535 lift/w 1.6 roller rockers
Exhaust 230@50  .544 lift/w 1.6 roller rockers
15/8" headers  21/2" exhaust/ mufflers
TKO 600 5-speed  3.36 rear gears

Thanks once again, and I'm really looking forward to doing some tuning!!!

Forrest Miller

comp:
which Vortec's ??? thats seem's like a little high on the lift

FORREST MILLER:
These are reworked 062 castings, 1.43" springs, cut down valve guides ( good to .550" lift), blended exhaust and intake bowls. I used to have them on my stockcar ;)

comp:

--- Quote from: sstocker31 on September 13, 2008, 12:44:11 PM ---These are reworked 062 castings, 1.43" springs, cut down valve guides ( good to .550" lift), blended exhaust and intake bowls. I used to have them on my stockcar ;)

--- End quote ---

 OK, isn't that close if you bounce a valve ??? i ask because i want to build a engine with Vortec's

FORREST MILLER:
Well,................. the whole Idea is to have your valvetrain under control at all times. When you start floating valves then you wind up breaking Parts ( pushrods, rockers, pistons ).  I spun my engine to 7500 RPM using Comp 987 valvesprings, and never once had any problems, and that was with .534"lift.  I still had lots of room left before metal to metal contact because of the valve seals I was using,( good to .550" lift with the seals in place).

Use good springs for your application, keep things under control, and you shouldn't have any trouble ;D

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