Need them carb guys and opinions

39F

39F

Master Mechanic
Sep 9, 2019
316
63
Pittsburgh PA
I got my 427 10.5-1,oval port heads , strip dominator, very small cam 515/520 lift ,238 at .50 so I got a 850 double pumper here's my dilemma people keep saying I can use a bigger carb but a buddy got a Holley 850 HP he'd let me try and buy it for 200 ,I want more tuneability , I was gonna take my 850 mill off the choke horn and install air bleed jets need some input
 
565bbchevy

565bbchevy

Geezer
Aug 8, 2011
7,510
113
Michigan
I ran a 850 race carb on my 496 BBC and it worked well, I would try your buddy's carb and having screw in air bleeds is a nice option for fine tuning the circuits..
 
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TURNA

TURNA

Rocket Powered Basset Hound
Jul 24, 2009
11,007
113
Socialist NY
What heads?

049 or 781?
 
TURNA

TURNA

Rocket Powered Basset Hound
Jul 24, 2009
11,007
113
Socialist NY
781s 219/188s ports cleaned up with bowl work
I ran a 950HP on mine with 049s, larger valves and a ton of port work.

Bigger cam and higher compression

It was to much

I put an 850 Proform on it then put smaller jets in it.

shes unstoppable!!!!!!!!!!!!!!!!!!!!!!
 
39F

39F

Master Mechanic
Sep 9, 2019
316
63
Pittsburgh PA
I ran a 950HP on mine with 049s, larger valves and a ton of port work.

Bigger cam and higher compression

It was to much

I put an 850 Proform on it then put smaller jets in it.

shes unstoppable!!!!!!!!!!!!!!!!!!!!!!
A 850 was too much for it?
 
TURNA

TURNA

Rocket Powered Basset Hound
Jul 24, 2009
11,007
113
Socialist NY
A 850 was too much for it?
950 HP was

I lowered the jets 2 sizes in the Proform and I am extremely happy with it.

A bigger carb doesnt necessarily mean more power, you have to find what works with your setup
 
lilbowtie

lilbowtie

Comic Book Super Hero
Jan 7, 2006
3,059
113
Canton Mi
If you use a carburetor CFM calculator, you will find you have more than enough carb. Wideband tuning will tell you everything you want to know. Don't try building a carb for what you want - buy it.
 
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pontiacgp

pontiacgp

blank
Mar 31, 2006
28,220
113
Kitchener, Ontario
we used a holley 500 2 barrel on our SBC 604 crate in our sportman which was chipped at 6300 rpm and we never always ran up front and the engine would hit it's chip before the end of the straight. The guys with the built motors could use a 4 barrel and they never pulled us down the straight
 
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39F

39F

Master Mechanic
Sep 9, 2019
316
63
Pittsburgh PA
we used a holley 500 2 barrel on our SBC 604 crate in our sportman which was chipped at 6300 rpm and we never always ran up front and the engine would hit it's chip before the end of the straight. The guys with the built motors could use a 4 barrel and they never pulled us down the straight
We use 500 rodchester in our class on our "stock" 350s at our track we definitely run out of air quick ,end of the year couple guys put 3310s and Victor juniors on and picked up 5mph and times were alot quicker too ,how big was your track
 
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