327 in '68 Malibu

[vds]

I've just rebuilt a 327 SB Chevy in a Malibu for road use mainly with an occasional trip to the dragstrip in mind It has flat top hyper TRW type pistons, stock rods and crank, 10:1 comp ratio, Pro iron heads as cast 200 runner, cam is an old General Kinetics hydraulic, with 224/234 @050, 114 lobe sep, In 110 installed at 106, .310" inlet lobe lift and .325" ex lobe It has 1.5 rockers on the ex and 1.6 on the inlet, Performer 2101 manifold, and 4-2-1 exhaust with 1 5/8" primarys, Quadrajet with 1" spacer, and HEI distributor with the Crane diaphragm. Can anyone suggest what needles and jets etc the Quadrajet would want as a starting point ? I'm not sure what this carb was off, it has 17059595 then 3091 CXK stamped on it Thanks

[novadude]

It's impossible to make a metering rod and jet recommendation without knowing air bleed sizes, as these varied greatly on different model carbs (not to mention the differences with single main air bleed carbs that used .036" tip rods vs dual main air bleed carbs using 0.026" rods).

As a rule, I would start with a stock rod and jet combo and work from there using a wideband to guide you.

I know you didn't ask, but if I may critique a bit....

Did you deck the block? flat top pistons and 64cc heads with .025" deck height, and a typical 0.039" composition gasket is going to put you at around 9:1 in a 327 (Plus or minus). That's not much compression for a 224/234 cam on a 114 LSA in a small engine with 200cc ports. It would run a whole lot better with something like a Isky 270 MegaCam (270/270, 221/221 @ 0.050, 108 LSA), or something else in the 215-224 @ 0.050 range on a 108-110 LSA. I would think the current combo would tend to be a bit 'soft' at low RPM, and the 2101 intake is not a good match for high RPM.

In a heavy car like a Chevelle, I think you are going to need a lot of stall and a lot of gear to be happy with that combo. If you plan on 3.3x gears and a stock converter, I think a stock '68 275hp 327 would likely give it a good run (based on a bit of experience with street 327s).

Assuming this is just a street car, from what I see, you have a bit too much cylinder head CSA, too wide LSA, and not enough compression. Just my $0.02.

[tenxal]

Sounds like a nice little package.

The 17059595 carb is originally a '79 305 application. The factory jetting, metering rods (front and rear) and rear metering rod hanger are a good place to start. QJets have a pretty forgiving window when it comes to jetting, if all else is correct.

FWIW, the earlier ('69-'71) QJets are a bit easier to tune than the later ones.

[F-BIRD'88]

To correct the compression ratio replace the .040" head gasket with a .015" thin steel shim style head gasket. Felpro 1094. 9:1 to 9.6:1
If you want to take it further mill the head to 61cc.
Now you got 10:1cr. Just right for that cam.

With that cam in that motor installed on a 106-107 intake C/L re-curve the distributor
for a short 10deg mech advance curve, allowing 24-26deg initial base timing
and 34-36 deg max mechanical advance all in by 3000-3200 rpm.
You cannot get this just by swapping advance springs. you need to limit the mech advance travel to 10deg.
Then also limit the vac advance max limit to 10-12deg too,

It will really appreciate the increased idle timing.

Its going to want a 10" converter 3000-3500 stall rated.
Its going to want 4.10's 4.30 gears in a 68 Malibu.

As said start with the stock Qjet jets and metering rods first.
You can then tune and dial in the carb with either a wide band or a narrow band AFR gauge. The cruise and low speed is all about the primary metering rods
and jets... The power is all about the secondary metering rods and rod hanger height and air door adjustment.

if it does not have gears and a converter make sure the carb spacer is a split/divided style spacer that keeps the plenum fully divided.
A open spacer will kill the low end torque curve if with a stock stall and mild stock 3 ish gears.
if you can find a Performer RPM Qjet intake it is more powerfull.
If using a Square flange perf RPM intake and a Qjet adapter be sure it is split style not open. Modify a 4 hole Q jet adapter to split style.

Its going to want what it wants for carb jetting. Edelbrock sells jets and rods for the Qjet. There is a high perf .135" inlet needle seat for this.

[vds]

OK idle restriction size .050" (about 10 o clock looking down at the primary throttle bore) channel restriction .048" (about 11 o clock position) 51P primary needles, primary jet stamped 71, AU secondary needles, tube sizes are, large .076" and small .036", hanger is 33797

Critique is welcome It has zero deck, block and heads were machined to arrive at 10:1 I figured the cam wasn't the ideal choice, but we already had it, along with most of the other parts used, other than the pistons/rings, bearings, gaskets etc
The heads came from the maker as leftovers, and were one small chamber and one large chamber, so they were machined to make a pair The car had a 307 originally, and finding pistons off the shelf was an issue. I had a 350 block, and 327 pistons are a lot easier to find, so it became a 327 The owner is retired and didn't have $ to burn, so we used as many parts as we had about the shop What manifold would be a better choice than the performer ?

It has a powerglide transmission, and about 800 rpm higher stall converter, with 3.08 rear ratio

[F-BIRD'88]

It has a powerglide transmission, and about 800 rpm higher stall converter, with 3.08 rear ratio

It will be a dog... That cam in a 327 in a 68 malibu needs serious gears, a th350 and 10" 3500 stall. A 9" race converter and 4.56 is not too much.

That 224-234 114 LSA cam works real good with the 142-144 lil roots blowers in a low cr SBC Another option for that car/cam/327 lame gears is nitrous oxide injection.

Change the cam. Something small duration 211 or LESS @.050"
It will be better in every way.
EG" comp cams dual energy cs-265DEH-10 211-221 .442 .465 110/106
PN 12-208-2

The open carb spacer is a big mistake on that setup.
Modify a 4 hole Q jet adapter to "split style" You want the divided plenum.

[F-BIRD'88]

The carb jetting looks fine as a start point. The carb is not the critical thing here.
Its the cam and trans converter/gears mismatch thats killing this combo.

The Performer RPM SBC (not air gap) intake is a better intake in every way.
As said the earlier pre 1974 4MV style Q jet carb is nicer to use on this comb.

[vds]

The spacer under the carb is a divided spacer

[F-BIRD'88]

It will be a very good Highway Car but not so much for the drag strip with the glide and 3.08"s.

[novadude]

It has zero deck, block and heads were machined to arrive at 10:1

That sounds better. I was assuming that it was not zero-decked - Compression goes out the window quick if you do not pay attention to these details on the little SBCs. The 10:1 compression will help.

However, I agree that it will be a slug with a Powerglide and 3.08s.

I had a ~9.5:1 CR 327 with a 264/272, 214/218 @ 0.050, 110 LSA cam in a Chevy II with a PG and 3.08s for a while. It still could have REALLY used a 3-speed, but it ran fairly well with a PG. Cam made enough low-end torque that it worked *OK* with the 'glide. Something like a Crane Energizer 272/272, 216/216, 110 LSA (or Summit-brand equivalent) would be a good inexpensive choice if you are not too far along.

I like the Performer RPM Q-jet manifold if you can find one used and cheap. If not, the 2101 might be OK and give similar performance with a divided spacer.

I disagree with the poster above that said the 69-71 carbs are more tunable. You can make the 75-79 carbs run as good as the old ones, and they have a better APT feature. Start with stock rods and jets and work from there.

[pdq67]

It will be a very good Highway Car but not so much for the drag strip with the glide and 3.08"s.

Might drop the engine, trans, and rear end gears into an early, box Deuce only due to size and weight.

Get your ride down around say, 2700 pounds and a lot of troubles/mismatch will go away, imho.

pdq67

[cv67]

spend or invest 200 in an AEM 02 sensor, it will tell you what your carb needs what and where. Youd be amazed at what at the difference of a "runs good" motor may act after you get things in line. Seen a few guys pick up a LOT and they never knew before just assumed cause it pulled good that was all they could get out of it. WAnting one myself.

How is he going to get a 68 a body to 2700 lbs?

[kirkwoodken]

I would avoid the glide. Impracticable in a good running street car.

[pdq67]

spend or invest 200 in an AEM 02 sensor, it will tell you what your carb needs what and where. Youd be amazed at what at the difference of a "runs good" motor may act after you get things in line. Seen a few guys pick up a LOT and they never knew before just assumed cause it pulled good that was all they could get out of it. WAnting one myself.

How is he going to get a 68 a body to 2700 lbs?

Again!

"Might drop the engine, trans, and rear end gears into an early, box deuce, only due to size and weight. "

pdq67

[rustbucket79]

Glides work best with a minimum 5000 stall, then gearing is irrelevant