Tuning Idle Pontiac 400 with 17058276, Comp xe262h

[PonchoVia]

Making changes to this engine which creates carb question.

Called Jeff at Kauffman and changing #96's to Kauffman 74cc D ports. 310 CFM.
Kauffman is having a custom grind done for a new roller cam. Should be 10.2ish compression.

Still want the quadra-jet. (its fun to send modern Mustangs, Camaros and Corvettes home from the autocross).

Still keeping the 200-r4, and the 3.25 for now.

Carb setup. 17058276 Previously installed Cliff's kit, 73 jets, 44 rods, float level 17/64.

Will I   need to change this carb recipe? My mind says yes but more air will pull more fuel so I'm not gonna guess.

My AFR shows good to barely lean with the old config at light throttle. WOT is pretty fat.11's.

[Cliff Ruggles]

What are the cam specs?

Unlikely you'll need to do a lot of tuning far as jet/rods, but the idle system must be set up for the CID/cam/compression so it's happy.

The new set-up will be more efficient as well, so most likely you will not be adding fuel.   My 455 with over 11 to 1 compression and KRE 295cfm heads uses basically the same carb and its fine with 73 jets, 44 primary rods and 44 secondary rods.  Just a tad "fat" at WOT but better than being too lean.....IMHO.....Cliff

[PonchoVia]

OK, finally have all the info for the setup:

462 cid, Kauffman Aluminum D port heads, 85cc, 310cfm 4.25 stroke forged crank, H-beam rods, Ross -6cc pistons,
Cam is comp roller from Jeff. 232-238@.050, 113lsa, with 1.65's will be .590's lift.
Ram Air exhaust manifolds, Edelbrock RPM intake. calculator shows 10.45

Gonna be pulling a lot more air thru this carb now compared to an 8.5 400 with 96's.

again, autocross car, auto trans, 2600-2800 stall, 3.25 ford 9inch

recipe still recommended? or any changes?

[Cliff Ruggles]

It will be fine.  Pretty similar engine combo as I'm running with the same basic carb.

I use 73 jets, our custom 44 rods, DA secondaries and same idle set-up as I recommended earlier in this thread.

You may need to go to a larger N/S assembly, and fuel delivery system for that power level.  Not sure what you are using now, but to keep up with that kind of power takes a "garden hose" for fuel delivery!......Cliff

[PonchoVia]

I purchased A low profile Carter fuel pump to run the quicker Camaro pitman arm
Will that pump keep up?
I

[Cliff Ruggles]

Those pumps are known to give nose bleeds.......when you run out of fuel at the top of first gear and your nose bounces off the steering wheel!!!!....LOL...

[PonchoVia]

hahahaha! oh shoot!