The time has finally come to pull the 312 out of my 56 Fairlane. Project includes C4 swap and installation of the following.



Set of G heads milled .020"

Reds Headers

Blue thunder intake

525 Demon Jr

MSD distributor and coil

Mummert's Y-265s cam 265 duration (224@.050) 110 separation



Whole bunch more wife doesn't know about



I don't know yet if engine has been bored or what the deck height is. I'm looking more for torque than Hp and have a couple questions.



Thinking about advancing the cam for more low end but how much 2 degrees, 4?



Carb spacer sounds like a good idea and after doing some searches on the forum I know a 4 hole is the way to go but should it be a 1" or 2".



Also looking through the posts I see most recommend richer main jets. Any ideas for a good starting point.



Thanks for your input. Mike as excited as a kid on Christmas eve

1956 Fairlane Victoria (ORREO)

 

Overlooking Beautiful Rimrock AZ

Yellowwing,

I used a Mummert Y272 cam and advanced it 4* on a 292 .060" over with G heads shaved .020" decked to pistons .010" in the hole, B manifold with 4100 carb and it is very strong on low end torque. had to finally put the 9" rear end in.

Now I need headers and bigger exhaust.

55 Vicky & customline

58 Rack Dump, 55 F350 yard truck, 57 F100

59 & 61 P 400's, 58 F100 custom cab, 69 F100, 79 F150, 82 F600 ramp truck, 90 mustang conv 7 up, 94 Mustang, Should I continue?

It’s usually a good practice to start off with the jetting that’s supplied with the carb and then make adjustments from there.  Every engine is slightly different so what works on one persons engine may not necessarily work on yours.  But with the Isky E4 cam in my 272 and with a 1” high 4 hole carb spacer, I ended up going with larger primary jets in my Road Demon Jr. 525cfm from #58 to #61.  Off idle drivability saw an immediate improvement.

Lorena, Texas (South of Waco)

Regarding the carb spacer: Why is the four hole preferred to an open spacer.

Thanks,

Richard

The Y factory four barrel manifolds are a "dual plane" - and "air gap" - style manifold - both are well known concepts that build torque at low(er) rpm ranges. Use of the four hole spacer not only provides a thermal break between the iron and the carb base plate - but preserves the dual plane chambers of the manifold. 

 
 Steve Metzger       Tucson, Arizona

Is there a significant difference in insulation between the plastic and fiberlike phenolic spacers?

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.

Then why does the Mummert manifold and carb spacer have two holes?

Ol'ford nutCentral Iowa

56 Vic w/292 & 4 spd.

On the Mummert intake and my blue thunder you will notice a divider down the middle of the carb opening. This separates the two plane of the intake. A four hole spacer has material down the center that seals and preserves this separation ( two oblong holes front to back would also work but spacers are not generally made this way). A single square hole in the spacer allows for the free flowing of air between the two planes. Does this help explain? Mike

1956 Fairlane Victoria (ORREO)

 

Overlooking Beautiful Rimrock AZ

Answers the same question I was wondering about.







Does someone have an answer for this? A difference between plastic, fiber, or metal? I'm sure they transfer heat differently and therefore one is more desirable than the others?

Heber City, UT (15 mins outside of Park City- basically it's in the mountains)

55 Effie

There is a particular problem with the four hole style spacer that the slotted version avoids. It maintains the side for side division of the "cross-H" style manifold - but prevents the primary butterflies from being shrouded (?) as they swing down into the cylindrical passage of the four hole spacer.

 

This illustration was created to show a particular problem that occurs when the 4 hole spacer below the carb is stepped (smaller bores) and the primary butterflies swing near the step. On a manifold that has the slot style opening, there is nothing behind the primary to interfere with smooth passage out of the venturi throat. 

My tests with the infared thermometer shows the phenolic spacers to be way superior to the aluminum or pot metal versions when it comes to preventing temperature rise of the carb baseplate.

 
 Steve Metzger       Tucson, Arizona