[F-BIRD'88]

Your best idle timing is going to end up between 14 and 18deg with that 214-224 442-465 cam.
Correct throttle idle position ON all 4 barrels at idle is CRITICAL.

Do not confuse the timing curve I recomend forr a hot-racey cam, on all cams or your cam.

Idle circuit is ubbber critical.... shooter pump shot tuning is soo easy once the idle circuit is correct

and near impossible when the idle circuit is fubared. (incorrect thottle positon)
Don't shoot your self in the foot.

ALL TUNING WILL BE DONE INITIALLY WITH NO VACUUM ADVANCE, Including drive testing.
Vacuum advance tuning comes in last after every thing else is dialed in.

[F-BIRD'88]

Did you blueprint the balancer timing tab yet?
True TDC....using a piston stop

Check for vacuum leaks.... PB booster,, trans vac modulator, carb base, intake,,, corvette vacuum operated acessories (head light doors) ( A/C...heater duct control)

the intake bolts WILL NEED retorqing. (by hand)

I run a cold manifold...but I don;t drive in the winter. ( and my engine combo is much more radical and racey..
(its very drivable and smooth 'cause I spent the time to dial it all in.)

On your car....I would start with one side blocked off and one
side with a 1/2" hole in the intake gasket so you have a "warm manifold"... A warm manifold is easier to tune correctly. A Hot manifold, too hot is a pain..(full open heat risers).. a cold manifold is harder to tune for especially this time of year.

Its all about finding the sweet spot.

[bygddy]

Originally Posted by F-BIRD'88

With such a mild cam and more initial I hope I will be OK running on the primary idle circuit and leaving the secondary closed up?

This is wrong. The holley carb idles using both the primary and seconday throttles.
It idles on all 4 barrels at once.

set it up so all 4 are even. You want even "4 corner idle" Thats the beauti of a holley. Don;t fugg it up by closing the sec throttles at idle.
That is not how a holley works. Don't shoot your self in the foot.

From that point the idle speed is fine adjusted by base idle timing, PCV system air flow (PCV valve choice) and fine adjustment of the throttle(S) position at idle.
Closed sec throttles will create the primarys to be too far open.
You want balanced 4 corner flow at idle.

recurve the distributor after you find the best idle timing, throttle position
PCV flow balance.
The throttles ALL 4 throttles must be in the sweet spot at idle for the idle and idle transition to work correctly and smoothly.

99% of the holley problems are tuner error, not carb design problems
That goes equal for Qjets and Edelbrocks too.

Q jets and edelbrocks are different.

Well there's something else I learned today, I was always under the impression you only used the secondary idle circuit if it was needed. Before I install it I will adjust accordingly. Thanks! I replaced the needle and seats today just because these were unknown and i had new ones in stock, I also have a multitude of pv's, should i replace and what size would u suggest?

[bygddy]

Originally Posted by F-BIRD'88

Did you blueprint the balancer timing tab yet?
True TDC....using a piston stop

Check for vacuum leaks.... PB booster,, trans vac modulator, carb base, intake,,, corvette vacuum operated acessories (head light doors) ( A/C...heater duct control)

the intake bolts WILL NEED retorqing. (by hand)

I run a cold manifold...but I don;t drive in the winter. ( and my engine combo is much more radical and racey..
(its very drivable and smooth 'cause I spent the time to dial it all in.)

On your car....I would start with one side blocked off and one
side with a 1/2" hole in the intake gasket so you have a "warm manifold"... A warm manifold is easier to tune correctly. A Hot manifold, too hot is a pain..(full open heat risers).. a cold manifold is harder to tune for especially this time of year.j

Its all about finding the sweet spot.

Yah, in had verified with a stop my tdc awhile ago, all was good there. This is about as much cold as the car will see, bout 5° and it seems to run fantastic with the riser blocked. No vacuum leaks, headlight leaks were many when i first got it home and that was the first thing I addressed.

[bygddy]

Originally Posted by F-BIRD'88

Your best idle timing is going to end up between 14 and 18deg with that 214-224 442-465 cam.
Correct throttle idle position ON all 4 barrels at idle is CRITICAL.

Do not confuse the timing curve I recomend forr a hot-racey cam, on all cams or your cam.

Idle circuit is ubbber critical.... shooter pump shot tuning is soo easy once the idle circuit is correct

and near impossible when the idle circuit is fubared. (incorrect thottle positon)
Don't shoot your self in the foot.

ALL TUNING WILL BE DONE INITIALLY WITH NO VACUUM ADVANCE, Including drive testing.
Vacuum advance tuning comes in last after every thing else is dialed in.

Thats funny and bang on correct, I creeped up on the initial until it pinged just a tiny bit on 92, switched to 94 and even on the hottest days it had no evident knock and made best power at 18. Only then, after reading a bunch of your stuff on vacuum advance did I try that, and even using manifold instead of timed it seemed to have much better tip in, cleaner idle for sure, and no detonation. I had pulled a plug to look for anything weird as I have zero tune up time on the qjet and the plugs looked clean, no peppering, goldish colored so I reinstalled. It actually runs amazing as it sits. And its suprisinhly very quick. I just want more, I'm determined to put it in the 12's using stock bottom end and hand me down or swap meet parts next spring. That's why I'm trying to stay away from solid cams or roller stuff etc etc. I'm def going to swap cams in the spring, and hopefully just some summit long slot rockers. My machine shop guy said he wrote down all the measurements I told him you said I needed. So i will dig out my paperwork and see what it says. That will help determine my cam choice, but again, budget hyd flat is likely. Stock pushrods, pinned studs and go from there. The guys I hang out with think this stuff is pure stupid, everyone wants a roller cam, alum name brand heads etc etc..and think what I want to achieve is impossible without spending huge money.....difference is, i have so little money in it, I'm not afraid of hurtimg it at all....makes it lots more fun lol...

[F-BIRD'88]

When I had that same cam in my 10 year old +60 over 350 vortec motor it ran very very well
great performance great daily driver good on gas etc etc etc..
The thing would not click off a 12sec et thou. 13.01 13.02 13.00 13.04 @104.5 105MPH No matter what I did it just did not want to give me a 12sec time slip. But it ran real good. 4.10's 3500 stall. 10:1cr.

Found out only later that the mechanical fuel pump (130gph rated) was in fact limiting the cars top end performance.... fuel flow.carb starved. I have since corrected the problem and ditched the inconsistant mech fuel pump.
It became immediately evident once the 406 motor went in. (it's near 500hp)

This fuel issue at the time also limited my ported 305Ho head testing too meaning the ported 305HO heads were working even better than my testing indicated but the stupid fuel system limited it.
That race 350 w/305 heads, big solid cam and 12.65:1cr combo flew even with the fuel flow limitation.
That was a low buck weapon. Never got to the nitrous on that one. (because I knew there was a issue with the fuel system on the car but had not nailed it down yet.. it would come and go.)

There is a 12 sec ET in your car...

Power valve with that cam will not be that critical it will be a fine tuning element controling when the carb switches from cruise AFR to power AFR as you get into the throttle 4.5", 6.5" 10.5",,, vacuum gauge,, afr meter
and drive testing.. The power valve opening point does not effect WOT tuning or power. When you rug it, the power valve immediatly opens.
The power valve should stay closed at idle. (idle manifold vacuum, in gear) not an issue with that mild cam.

Do not confuse part throttle cruise wher the carb is on the idle off idle transition,,, with higher road speed cruise when the carb is on the primary main jets. Many people get this wrong and mess with the main jets when the problem is the idle circuit transition. The idle and off idle circuit is ubber critical.

70 to 74 pri and 80 to 85sec jets all all just fine for this carb on the RPM manifold on your motor.

[bygddy]

Hey f-bird, things got a liitle bit more intresting today, one of the guys I hang out with has changed directions on his 406 build, so he offered me me his XE284 cam and long slot rockers for 200$. They are new in boxes......is this something I can use in my current set up? Heads are good to 550 I'm told according to my machine shop guy after I asked your appropriate measurements. Whether they will flow that is of course another subject....sticking with my welfare build this sounds like a decent deal to me if it will work....the converter i got is the b&m 20413, and 411 gears....and as above the 4779 Carb....power interrupt switch, lock timing at 34-36, 3.5 pv, 70-80 jetting, does this sound like a street slug or something that's actually going to get me the damn 12sec et I want so bad for very little cash? I have no issue shifting the thing at 6500 till it eats itself....assuming the heads flow enough to warrant it.....what's your and anyone else's input?

[vinniekq2]

try it,its not a big investment.

[bygddy]

Originally Posted by vinniekq2

try it,its not a big investment.

True, but having to pull the Rad, and front of the motor down only to have to do it again would suck....as it is I need to drop the oil pan this time and replace the front cover, never pulled the pan on one of these but indont think there is much in the way?

[F-BIRD'88]

It will work well. Better with a 3500 stall. I run that cam in my 406.
use locked timing and ported vac advance . good match to your carb and intake. and purpose
Do not assume lift clearance on heads (Retainer to seal). Measure it your self.
.507" .510" This cam needs good springs and quality lifters. Works well.
You will like this one in your vette. very strong from 3000 up. Degree it for best results.
You do not need to drop the pan to change the camshaft.

Molyslip Canada Inc. :: Molybdenum Lubricants, Performance Lubricants, Copaslip Anti-Seize, EP2 Grease, Wear Reducing Lubricants, Oil Additive

Remove first few oil pan bolts in front of oil pan, loosen a few more.
Just pry the pan down a hair,just enough to slip the timing cover back on, after
trimming the corners of the timing cover.

Be sure the springs are all installed correctly at correct height. 305 head have deeper exhaust spring
seat. requires a .105" (.060+.030+.015) stack of spring shims to correct, when ex rotators are eliminated. 6800+capable with the correct springs. 6000-6400 shift point is plenty.
Cool idle 3.5" or 4.5" power valve., jetting is fine.
The valve train will not be perfectly quiet with this cam. It has fast action and agressive ramps.

It will GLH.

[vinniekq2]

why do you have to pull the pan?

[bygddy]

Originally Posted by vinniekq2

why do you have to pull the pan?

I have had exactly zero success rate with getting the timing cover to seal with leaving the pan on.....and I don't wanna deal with leaks after words....

[bygddy]

Originally Posted by F-BIRD'88

It will work well. Better with a 3500 stall. I run that cam in my 406.
use locked timing and ported vac advance . good match to your carb and intake. and purpose
Do not assume lift clearance on heads (Retainer to seal). Measure it your self.
.507" .510" This cam needs good springs and quality lifters. Works well.
You will like this one in your vette. very strong from 3000 up. Degree it for best results.
You do not need to drop the pan to change the camshaft.

Molyslip Canada Inc. :: Molybdenum Lubricants, Performance Lubricants, Copaslip Anti-Seize, EP2 Grease, Wear Reducing Lubricants, Oil Additive

Remove first few oil pan bolts in front of oil pan, loosen a few more.
Just pry the pan down a hair,just enough to slip the timing cover back on, after
trimming the corners of the timing cover.

Be sure the springs are all installed correctly at correct height. 305 head have deeper exhaust spring
seat. requires a .105" (.060+.030+.015) stack of spring shims to correct, when ex rotators are eliminated. 6800+capable with the correct springs. 6000-6400 shift point is plenty.
Cool idle 3.5" or 4.5" power valve., jetting is fine.
The valve train will not be perfectly quiet with this cam. It has fast action and agressive ramps.

It will GLH.

Currently I have comp 981 springs with about a month or 2 run time on them. Will these get the job done or is an upgrade absolutely required.....?

[F-BIRD'88]

Comp wants you to use something a little better for this camshaft.
They recomedn their medium size 986-16 spring.

I use a stock diameter high pressure single spring with similar seat and open specs.

This Summit racing Spring is similar to what I'm using
SUM-174000
Others are Lunati 73943
Isky 235D

Pioneer 810107-4
Pioneer Automotive 810107-4 - SummitRacing.com
You need to order 4 units to get 16 springs
They are packed as a 4 spring set pack.

Crower Performance Valve Springs 68304-16

Comp valve spring shim kit #4753 You need this to correctly shim the deep exhaust spring seats
to get the installed height right.

[bygddy]

Originally Posted by F-BIRD'88

Comp wants you to use something a little better for this camshaft.
They recomedn their medium size 986-16 spring.

I use a stock diameter high pressure single spring with similar seat and open specs.

This Summit racing Spring is similar to what I'm using
SUM-174000
Others are Lunati 73943
Isky 235D

Pioneer 810107-4
Pioneer Automotive 810107-4 - SummitRacing.com
You need to order 4 units to get 16 springs
They are packed as a 4 spring set pack.
..

Crower Performance Valve Springs 68304-16

Comp valve spring shim kit #4753 You need this to correctly shim the deep exhaust spring seats
to get the installed height right.

Should pick up the cam this weekend. And after I figure out heat for my garage I will likely pull the tranny, then get the heads off and go from there. Yes I will upgrade the springs then if you think its a must. Think maybe I will splurge on arp headbolts this time around lol....