All Big Six Fabbing intake on efi lower.

Relates to all big sixes

benchracer

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View attachment 9211
I havent finshef this build yet, already thinking about building a second 300.
Have 2 more cranks and two blocks

Punch one .050 over and run some forged 360 pistons

Ones a 240 so I guess those rods are out.

Just thinking out loud.

You guys wanting me to run two garbs got me to thinking. Thats alot of carburation it requires a complete redo of the top of my intake would be a conglomeration of throttle linkages

I like simple. though what I did probly wont turn out to be simple. Bought a 600cfm 4160 for 70 bucks.
Ill set secondaries to come in late
Probly only be used while my foots on the floor with our 10k skidsteer in tow on the 5k goosekneck Trailer.

Ive bought the 252h cam but wouldnt be aposed to ordering something else. But I almost feel like I may have made the right deciseion since some say it is tourque but has less power on top. Isnt that what a came geard towards lower rpms does. Thats what im after.

I dont have to stay with the comp cam. Ive got a cam that is stock and one that I think is a stock replacement.

Im probly making all the wrong calls on how to spend my money but im atleast learing alot.
 

benchracer

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like you turbo up top. our exhaust manifold will line up the ports upside down. been working on mounting plate for all bolts intake and exhaust. never enough time. your work is great
 

Evan76

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The turbo is just a teaser pick.

Thabk you

I thought about building straight off the head but decided the efi lower is already fabbed
 

111JESUS

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I'm thinking of removing the throttle body off the original plenum (upper) and fab an adapter in lieu of above TB & installing a 1v carb... what are the cons to using the upper unit this way?
 

Evan76

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Thats along ways for fuel to stay automized its designed to move only air.
But im definitely not smart in this area or any area really
 

111JESUS

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That was the 1st response I thought I was going to get. Looking into the plenum thru the throttle body, that bowl design screams of fuel puddling... and it appears a fair amount could accumulate in there... rife with precarious potential. Can you imagine a couple of cups of gasoline in that enclosed space and a "chance" backfire take place... shiver me timbers! So I'ma now discountin' that as an easy answer to my issue, but more likely it's a plan of the devil to hasten my face to face with God! Think I'll go have a look @ them Clifford's intake.
 

THE FRENCHTOWN FLYER

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There is a mate in Australia with a roadster who plunked a 4V carb on an EFI intake. Not the lower half - the whole EFI intake. There is a pic of the car on here somewhere.
 

BigBlue94

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Is that the technical carb tool in the background?
HAHA thats like a 10 lb deadblow. Not sure whether I had to use it on the float arm or to seat a threaded jet without a screwdriver :ROFLMAO:

I once set my idle at 2000 rpms just to keep it running at 240° to get off Hell's Revenge in Moab. I had to hotwire it too due to an overheated ignition relay. Then promptly went and changed my pants...
 

111JESUS

Active member
That was the 1st response I thought I was going to get. Looking into the plenum thru the throttle body, that bowl design screams of fuel puddling... and it appears a fair amount could accumulate in there... rife with precarious potential. Can you imagine a couple of cups of gasoline in that enclosed space and a "chance" backfire take place... shiver me timbers! So I'ma now discountin' that as an easy answer to my issue, but more likely it's a plan of the devil to hasten my face to face with God! Think I'll go have a look @ them Clifford's intake.
I looked... whole truck not valued as high... crying, whining and sniffling while headed out the door with the shootgun! Guess I better put this rabid thing down.
😪 Gotta' cut bait sooner or later...
 

Evan76

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Well my Budget 4160 I noticed doesnt have adjustable needle and seats. So I went back on the search for a 390 450 maybe 500cfm for 200 bucks. That was a no go . Only the 600cfm is affordable

looking through holleys refurbished carbs, 600cfm street warrior is now enroute 229 free shipping adjustable floats.


Also im pretty sure 1/2 spacer isnt enough to clear linkage from Plenum top. Ughhh
Might trace the spacer and cut a riser block.
20211203_213704.jpg

Slightly worried im not going to clear the hood
 

CNC-Dude

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You will have better results from a plenum that is truly rectangular, than trying to widen the top to the 4 bbl width and then narrowing it down once you get past it. You still need to maintain a plenum volume that is around 3/4 the size of the cubic inch if it's a stockish engine build. A simple LxWxH calculation will give you that volume. If you intend on using a 4 bbl, then that dimension is fixed and the length and height can be easily adjusted to zero in on the target volume.
 

Evan76

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Thats pretty stick.

I just went for a ride in a bronco with a big six. Very excited now to get mine going
 

pmuller9

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Thats pretty stick.

I just went for a ride in a bronco with a big six. Very excited now to get mine going
I’m hoping to persuade you to use a cam that will give you a very wide power band since you are doing a big valve, ported head. The cams that have power from an idle to 5000 rpm have .050” durations in the 220 degree range. The Schneider 140H is one of them. The others are the Crower 284HDP and the Howard’s 280996-10.

Don’t kill the potential you are working on everywhere else with a smaller cam.
 
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Evan76

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I completly get where your coming from

Regardless of cam I use im not going to rev it so ill never see the potential of the upper end.

What cams have the groove in the front20211204_204404.jpg20211204_204438.jpg20211204_204509.jpg20211204_204617.jpg cam journal.

The comp cam I just received and the one removed from the motor both have the groove.

The ford cam removed from my other 300 doesnt have the groove.

I might have to degree this old cam. Or decifer the markings.

Im not strapped to the 252h yet. Though im not completely convinced I need or want a bigger cam. Or even d

Abandoned said it best today horse power is direct result from rpm.
The more I gear the cam towards upper end the less I will be using it in its potential power Band.

My cummins has enough fuel and air to make 400horse but I rarely use 200horse. But im fueling pretty aggressive down low it definitely moves around with less effort and is getting very good fuel milage

Probly not a great comparison but its what I am used to

Im hoping for similar from this 300.
 
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BigBlue94

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Why are you never gonna rev it up? Honest question.

I take it you rode in AbandonedBronco's Bronco? I too have enjoyed that experience when we met in Moab. His has a real smooth powerband. And the ZF5 is so well suited to his build. He doing well? He has a cam with more lift than I do, and i think a bit less duration? Its an Erson cam. He is running 9:1 CR iirc. My build is a bit more wiley.
 

pmuller9

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I completly get where your coming from
Regardless of cam I use im not going to rev it so ill never see the potential of the upper end.

Im not strapped to the 252h yet. Though im not completely convinced I need or want a bigger cam. Or even d

Abandoned said it best today horse power is direct result from rpm.
The more I gear the cam towards upper end the less I will be using it in its potential power Band.
Most are disappointed with the results of the 252H cam over the stock cam.
The reason is the stock cam is retarded 4 degrees and closes the intake valve (.050" specs) at 30 degrees ABDC.
If you install the 252H cam per the cam card which is 4 degrees advanced the intake valve closes at 29 degrees ABDC which is 1 degree earlier than the stock cam resulting in similar performance.
The one advantage of the 252H is it has more valve lift and the intake valve opens earlier which is only an advantage if the exhaust system has good scavenging which the stock log exhaust manifold does not.

You can make the 252H work for you if you install it straight up with the intake lobe center at 110 degrees ATDC and use the Chevy six 1.75 ratio rocker arms for additional valve lift.
That will boost the power in the 1800 to 3000 rpm operating range.

What everyone else with larger cams is trying to convey is that even though the power band above 3000 rpm is emphasized they will make more torque below 3000 rpm than the 252H.

Of coarse the stock EFI exhaust manifolds should be used and long tube headers will further increase the low rpm torque.

The one thing that is overlooked is the ignition system.
There is no substitute for an MSD 6A or 6AL for making torque from an idle to 3000 rpm.
Several have tried and went back to the MSD system
 
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