REDUCING airflow in a 500 Holley....

[sc2dave]

Ok. The car has a stock Powerglide with a stock converter. It has an Rv cam. Gears are stock. The Offy intake is open plenum. The header pipes are almost touching the intake, no other heat source. The carb's air bleeds IFR and pvcr's are tapped. I am waiting for a fuel sending unit to start driving it to tune. I do have an LM-1 too. I measured the outermost diameter of the booster and it is .912 or so. I forgot, I measured the air bleeds and it was .160". The ifr and pvcr are smaller. Does anyone know what sizes they are,here in McMaster's website? I want to order a few to drill out.https://www.mcmaster.com/#cup-point-set-screws/=18dvhve

[F-BIRD'88]

You need to take the carb off the intake , bolt a little roots
blower on, and bolt the carb on that.
(Eaton M90, MP112)

Define "It's a RV cam" Is the engine compression ratio stock? (8.5:1)
A cam has a big effect on a small cid motor.
Magnafied if low cr too.

[F-BIRD'88]

If your intent rnd goal is to get the car to accelerate by
hot rodding the 194 six motor
you need to get the gearing right.

All the mods, intake, cam carb headers etc only add
more power at highrr rpm.. and at the expense of low
rpm torque and low rpm driving..

Get a 3 speed auto trans eg th180 (chevette) and its torque converter too.. you need a small diameter converter that when behind your 194 six gives a 3000+++ stall speed.
more stall speed is better. Don't know which small diameter stock oem gm 4 cyl and small cid v6 converters you can swap in to that th180 3 sp auto trans but a higher stall is better. but the chevette 3 sp auto trans and torque converter is a start.
others th200 th250 th350 with the chevette converter swapped in.

possible th2004r swap. big difference from a 2 speed pg behind that motor..
possible to us gm front wheel drive trans torque converters in this (citation, malibu v6) What ever gives the highest stall behind your 194 cid motor.
get yor head around 4.xx ratio rear gears.
5.13 is not too much..

Get the engine cr up to 10:1.. if you cannot do that
SUPERCHARGE/TURBO IT. otherwise the Rv cam is a waste.

[sc2dave]

You need to take the carb off the intake , bolt a little roots
blower on, and bolt the carb on that.
(Eaton M90, MP112)

Define "It's a RV cam" Is the engine compression ratio stock? (8.5:1)
A cam has a big effect on a small cid motor.
Magnafied if low cr too.

stock compression ratio. Did I measure the boosters correctly? From the top across? Why do I need a stall converter? It idles fine,vacuum is around 14". Doesn't jump when put into drive. Not trying to make a fast car out of it,just a cruiser with a 6.

[F-BIRD'88]

Because all your hot rod modifications change the torque curve. bigger cam bigger open plenum intake big carb..

if the "rv cam " you got is the popular.509" lift hyd cam.
elgin, clevite speed pro etc (291-291 224-224@.050" .509-.509" 108 lsa 113/103 it really wants a high compression ratio 10:1 and wants gears and a 3000+ stall.

low end torque will be lame. can be advanced quite a bit
to tweek the torque.

if you got the milder popular "rv cam" marine hp cam .464"-.490" 194-204
110 lsa 105/115 it is not so critical. it still likes higher than stock lame cr (8.5:1) and likes increased gears and converter stall.


If you want that big carb to work on that little 194 motor
you want to make the motor use lots of that big carb.

a plenum divider will help throttle response.
a diz recurve will help.

[F-BIRD'88]

It is a very big non progressive carb on that motor if only used for low rpm driving.

a restrictor will not make ut more responsive.

It is like a locked 750-800 double pumper carb where all 4 barrels open all 4 at once on a 390 cid v8 would be.

It will have throttle responce issues at low rpm.
gears help,, higher converter stall helps.
3sp auto or 3 sp + OD auto trans helps

Plenum divider helps. Reduced plenum volume helps.
long intake manifold runners helps. (like on a chrysler slant 6 intake..
Your offy open plenum with short shared runners intake
is going to be a challenge. (smooth low rpm driving and wot response from low rpm.

Ibelieve the highest oem converter stall is the powerglide converter from a 1971 vega pg or the pg converter from the old corvair with auto trans.

a aftermarket high stall converter will help.
a 3000 stall converter is rated behind a 350 v8.
don't expect 3000 stall behind the 194 6 cyl.
you will be n race converter (8" diameter) range to get even near the right converter for it to let it spool up enough to let that big carb respond to wot.
jnless you are ok with lame throttle response.

[F-BIRD'88]

On that motor and for your purpose that oem gm 2 bbl carb that is 1/2 a Qjet is a lot better for you.

The old gm 283 sbc 2 bbl (2G) is a better choice.

You can mwasure that carb all you want. it does not change
it. A restrictor under that carb will just make it less responsive and harder to tune... But a plenum divider may help overall.

[sc2dave]

Because all your hot rod modifications change the torque curve. bigger cam bigger open plenum intake big carb..

if the "rv cam " you got is the popular.509" lift hyd cam.
elgin, clevite speed pro etc (291-291 224-224@.050" .509-.509" 108 lsa 113/103 it really wants a high compression ratio 10:1 and wants gears and a 3000+ stall.



if you got the milder popular "rv cam" marine hp cam .464"-.490" 194-204
110 lsa 105/115 it is not so critical. it still likes higher than stock lame cr (8.5:1) and likes increased gears and converter stall.




a plenum divider will help throttle response.
a diz recurve will help.

cam specs are 110* lobe center,adv dur. is 264 ,210*@ .050. 478* lift. I was told total timing should be 36*. 1984 year grind! So a 4 hole spacer should also help? A plenum divider?

[CamKing]

You've got a 5,500rpm cam and converter, and a 7,000rpm carb.
Sell the carb, and buy a 350cfm 2bbl. That's your cheapest option.

[panic]

He's waiting for someone to validate what he's already decided to do.

[F-BIRD'88]

Since you are after it being a cruiser. with stock gears
and converter and it is stock compression Id be sure that that cam is advanced bit. say 110 lsa 105 in c/l.
It will respond to a diz recurve with that cam.
shorten the mech curve limit to allow more initial at idle 14 to 20 deg base idle and 34-36 ish at max mech adv.

a shorter quicker curve with plenty base initial.

A2bbl would use a 2 hole spacer. If it includes a divider plate that fully divides the plenum, isolating cyl 123 from 456 on the manifold all the better. IMHO.
you havr a lot of better carb choices for this job.

When you find out all this for yourself don't be hard headed.
Put the stock intake, carb and cam back in it.

It will then be a good "cruiser" in thar car with a pg and stock gears.

[F-BIRD'88]

Needs a lil B&m blower under that carb, with that cam.
Then you'd be "cookin with gas". Bolt a Qjet 4bbl CARB on the lil blower. Bolt the blower on a adapter to the offy open plenum intake.. You'd like that.
Then you'd have a cool "Cruzin" 6 banger Chevy II.

(you'd under drive the 144 blower about 15% ish for
moderate boost on your 194 cid mild cammed low cr 6 cyl.) A simple matter of top blower pulley choice.)

[F-BIRD'88]

correction you'd want to drive the 142-144 lil blower abiut 1 to 1 ratio on that 194 cid motir fir moderate street boost .
5 psi ish. A nice gain. You can get real serious by drivibg the lil blower faster on that motor.
Tons of range. Tons of power if you want serious stuff.
(high boost, high octane gas, water meth inj)
The capacity and potential is there.
a Easy 5 psi is a nice gain. For that motor.

[sc2dave]

He's waiting for someone to validate what he's already decided to do.

Wrong! I have heard different opinions, like in post 2,PeeJay states,"I don't think a 500 is too big for a 194. If anything it might be too small, the fewer cylinders an engine has the more it "likes" a larger carb. In post 5, MadBill states,"If it's a 2 bbl. 4412, remember that such carbs are rated at 3.0" Hg. pressure drop vs. 1.5" for 4 bbl., so a '500 CFM' 2 bbl. flows the same as a 353 CFM 4 bbl." Then jmarkaudio, which I do highly believe, states,"I don't think you would have any issue using that carb with annulars on it."

[sc2dave]

Is the offy 6 banger intake open plenum?

If more low speed part throttle response is wanted install a plenum divider. as said ignition curve must be correct.

powerglide trans?

Plenum is open, I'll try dividing if it'll help. Yes, Powerglide trans.