Qjet building

[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

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]

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

 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

[mikes74sd]

let mr cliff do the carb;but go to a performer rpm air gap intake-this intake is the real deal;and change to 1.75 headers and have fun

[Jeff Walker]

Take a penlight and shine in to the the accelerator pump discharge hole.  About 1/8 inch down into the hole you will a smaller hole that will be somewhere in the .025-.028 range.

[Cliff Ruggles]

What is the carburetor number?

The large main airbleeds are more of a problem than anything else.  It is difficult to get a good fuel curve with those carbs.  When we build them here in the shop, the main airbleeds sizes are reduced, and smaller main jets are used......Cliff

[FORREST MILLER]

The carb number is 17080207

[FORREST MILLER]

Mike74,

this engine is being built fo torque........will never see past 5500  RPM.  Changing those two components will defeat my goal..........Torque monster

[FORREST MILLER]

I stand corrected.......Thanks to JeffWalker I was able to find the correct holes for the squirters and measured the best I could ( I'm missing a few drill bits) and determined its about .026"

[FORREST MILLER]

So Cliff,

How about my carb ( 17080207), with the main airbleeds reduced to .070", setup to Recipe 2,with my engine combo......will that work OK?

Thanks, Forrest Miller

[Cliff Ruggles]

Recipe #2 should be really close.  We have custom screw in airbleeds and a jet/rod package for those carburetors, takes the hassle out of trying to reduce the airbleed diameters and coming up with the best jet/rod combinations........Cliff

[comp]

Recipe #2 should be really close.  We have custom screw in airbleeds and a jet/rod package for those carburetors, takes the hassle out of trying to reduce the airbleed diameters and coming up with the best jet/rod combinations........Cliff

 are these parts in your book ?

[Cliff Ruggles]

No, we sell them separately from our kits.  We did not put ourselves down as a parts supplier in the book.  The demand has been great enough since the book came out that we have stepped up and had a lot of parts manufactured, and started putting custom rebuild kits together, etc......Cliff