Help Choosing a Recipe

[beertracker]

Here is my setup;

Pontiac 400 cid, 8.6:1 CR, slight head porting, headers, dual exhaust, auto trans, 17057274 q-jet, 2200 rpm stall, Summit 2802 cam:
Cam Style: Hydraulic flat tappet
Duration at 050 inch Lift: 224 int./234 exh.
Valve Lift with Factory Rocker Arm Ratio: 0.466 int./0.488 exh.
Lobe Separation (degrees): 114.

application is weekend street.
factory HEI dist.
Ignition advance kit
Engine has lope at idle.
My throttle base is NOT drilled for air.

Question is which recipe do I use.   Recipe 1 page 111 of Cliff's book or recipe 2?  Maybe I am overly cautious but I don't want to select a too aggressive a recipe for my engine.

If you have questions just ask.

Thanks, BT

[Cliff Ruggles]

With that much cam in a 400 cid engine at 8.6 to 1 compression, it's going to need a lot of idle fuel and bypass air.  I'd use the 3rd recipe to set up the idle system.

I use the same carburetor on my 455.  I would install one of our kits, and tuning components.   It will need a quick release choke pull-off, jets, metering rods, and power piston spring.  I would also recommend converting it to electric choke, for instant cold starts and fast idle while warming up the engine......Cliff

[beertracker]

Hi Cliff:

Thanks for info & I have a few more questions.  I started modifying the idle circuit per recipe number 3.  I found the idle tubes, idle down channel, lower idle air bleed in main body, main air bleed (main body) and main air bleed (air horn) but I can't find the upper idle air bleeds either air horn or main body.   Can refer me to a page in your book where I see where these are located?

Also wanted to ask your recipe recommendation for the primary & secondary circuits.  Should I use recipe 3 for these?

A few months ago I installed your rebuild kit and no problems.

Thanks,
bt

[beertracker]

Hi Cliff:

Thanks for info & I have a few more questions.  I started modifying the idle circuit per recipe number 3.  Also wanted to ask your recipe recommendation for the primary & secondary circuits.  Should I use recipe 3 for these?

A few months ago I installed your rebuild kit and no problems.  From previous post I found the upper idle air bleeds.  If it was a snake it would have bit me.

Thanks,
bt

[Cliff Ruggles]

Don't worry about main or idle airbleeds with that carburetor, they are already where they need to be.  When you get time, call the shop and I'll spec out jets, metering rods and PP spring...thanks....Cliff

[beertracker]

I just finished enlarging the idle & main air bleeds per recipe #3.   Does this mean I have to now fill these with marine epoxy and re-drill to smaller diameter? 

bt

[Cliff Ruggles]

What size did you make them?  They were already right where they needed to be on that carburetor number.....Cliff

[beertracker]

lower idle air bleed  main body   .068"
upper idle air bleed main body   .068"

main air bleed main body           .068"   was .051"
main air bleed  air horn              .068"   was .065"

I made the air bleeds as close to recipe #3 as my numbered drills and micrometer would let me.   Only after I re-sized the air bleeds did I see your post about my carburetor already having the correct size air bleeds and no re-sizing was necessary.

If I have not trashed the carburetor by my re-sizing I still plan to call your shop and place a order for primary rods\ jets.
I have four power piston springs from HP rebuilt kit I bought from you.

[Cliff Ruggles]

Numbered drill bits don't come in any of the sizes that you listed.  They go from .052" to .055", and .064" to .067", and there is no .068" bit, at least in a set of 1-60 bits.

If you have all the bleeds at .068", just leave them as-is, they will be fine.  I'll adjust jet/metering rod sizes when you place the order......Cliff

[beertracker]

The .068" number I came up with was a micrometer measurement of my numbered drill.  So either my micrometer or numbered drill size is off.  The numbered drill set came from Harbor Freight so it's not "lab grade" or even close. 

bt

[beertracker]

Cliff:

Good talking to you & I am looking forward to getting the jets\rods.  What was that cam you mentioned you use in your shop for low CR Pontiac 400  like mine?  I forgot to write the cam info down.   The next time the engine comes out of the car I may consider a cam change?   

Thanks,
BT

[beertracker]

Cliff:

I am getting ready to drill the base plate for idle bypass air.  Should I start with .080" holes for now?   My setup is above.

bt.

[Cliff Ruggles]

It's going to need at least .080" bypass air.

For the low compression 400's, the best cam we have found is from Crower, pretty sure it's part number 60240, 210/221/112.

The Summit 2800, 204/214/112 also works well in them....Cliff

[beertracker]

Cliff, I received the parts and things are going good.  A few more questions.

1.  How many turns should I set the ATP for?
2.  Regarding the power piston spring which one should I use?  I have all four from your rebuild kit.
3.  As I increase idle bypass air in the base plate what drill increment size should I use?  I was thinking of going in drill increments of .010" or should I go larger?  I am sure there  is a maximum size idle air bypass hole  that I should not exceed.  What size is it?

Thanks, bt

[Cliff Ruggles]

3.5 turns up from seated with the APT screw.

Use the orange spring from the kit.

Don't add any more idle bypass air until you do some testing to see if it needs it......Cliff