Carburator spacer

[66chargertoy]

Hey folks Got myself a CH4B a while back and decided to swap my cast iron intake on the 440. I'm using a Proform 750 race carb. So here's the question, the cast iron intake was code dated to 1968 and had the four separate holes , square bore, so I had a four hole 1" phelonic spacer with a 4 hole gasket on both sides to match the intake. So now with the CH4B, which does not have the 4 individual holes but two slightly oval holes (aka dual plane) do I need to change my phelonic spacer to a open design as with the gasket

[Chryco Psycho]

not nessisarily , Spacer will have different effect on the way the engine responds the 4 hole may work very well on there

[Brightyellow69rtse]

4 hole ran great on my single plane street dominator on my old 400.

[Just 6T9 CHGR]

I ran a 4 hole on my CH4B with good results as well

[john108]

I still have a SUM-G1405 in a box, just waiting.  It has a big square opening.
The plan, if I ever get to it, is put it between a Proform 950 and a Holly street dominator, for a 505 stroker. 
Is this the correct shape, rather than 4 holes, to use? 

[Chryco Psycho]

Open spacer increase the plenum size but tend to reduce signal at the carb venturi the 4 hole do the opposite , they will increase plenum size a little but increase signal in the venturi so it may work well with the 4 hole still

[firefighter3931]

Hey folks Got myself a CH4B a while back and decided to swap my cast iron intake on the 440. I'm using a Proform 750 race carb. So here's the question, the cast iron intake was code dated to 1968 and had the four separate holes , square bore, so I had a four hole 1" phelonic spacer with a 4 hole gasket on both sides to match the intake. So now with the CH4B, which does not have the 4 individual holes but two slightly oval holes (aka dual plane) do I need to change my phelonic spacer to a open design as with the gasket

Denis, as we discussed ; the 4 hole will work fine on the CH4B and that's the one i would use. The 4 hole with give you a stronger signal to the boosters and provide sharp throttle response. 

I still have a SUM-G1405 in a box, just waiting.  It has a big square opening.
The plan, if I ever get to it, is put it between a Proform 950 and a Holly street dominator, for a 505 stroker. 
Is this the correct shape, rather than 4 holes, to use? 

John, the open spacer is a better choice with a build like yours. The 512 engine with a std port cylinder head will need increased plenum volume for upper RPM breathing. The smallish (for the displacement) cylinder head port cross section/volume will keep airspeed high and throttle response sharp. You won't be short on torque or low speed power 


Ron

[resq302]

since we are talking about spacers, my car just has the gasket between the carb and the intake.  Factory set up.  In rebuild kits, they always include that thick fiber type spacer.  Were they used on cars originally or just something that kits include that is generic?

[firefighter3931]

since we are talking about spacers, my car just has the gasket between the carb and the intake.  Factory set up.  In rebuild kits, they always include that thick fiber type spacer.  Were they used on cars originally or just something that kits include that is generic?

Brian, if you're having vapor lock symptoms the thick fiber gasket will help....personally, i'd use it 



Ron

[resq302]

Ron,

No vapor lock issues at all.  Just looking for correctness as always!