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4 Barrels of Fury (not dialup friendly)


jozefaz

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Where did u get the intake for the headlight?? I have been looking for one for a while.bit not even sure what its called...

 

Ive been thinking about printing a few out... maybe even set them up for some sort or insertable filter. If you google 'headlight intake funnel' there are a bunch of cheap options.

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So...long ago... I was told by a long time Datsun guy that most of the "Dual plane" and "Dual Port" Vertial intake manifolds, as well as the Various Single Sidedraft Manifolds, came about because of restrictions in various SCCA and other racing classes. Old ITC class rules, circle track restriction, single carb glasses, etc. He said, essentially, they are inferior to Dual Side Drafts of almost any kind (other than late model flattops) At the time my 510 had an Offy 'Dual Plane" and I was encouraged to return it to Pre-smog stock for the Weber.

 

I remember him going on something about 90 deg bends and air velocity, restricted port sizing (especially on offys) and necessary jetting needs VS fuel mixture issues of todays gas...

 

I ended up hunting down a set of SU's and have been infatuated with them since....

 

Anyhow, I am not trying to be a downer, I am just curious.... Its clear that you have the skill to get serious Fabbing done, What was it that led you to want this setup enough to do the quality work needed? Was it just easier and less costly to obtain and fab up? (it DOES look awfully sick :thumbup: with it all said and done) No doubt it is far superior to the gawdawful stock Carb on a 710 (which I currently suffer on mine)

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1976 l20b

 

the holley is a 4776 list (600cfm, NOT 650cfm) 2 corner idle. secondary vent and fuel inlet plugged

essentially i am running a carb smaller than a 2300

 

american SSS exhaust manifold with smog ports plugged ( or so i was told it was SSS, he said the jap version didn't have smog ports) installed a crankcase evac so no pcv valve. works awesome.

 

jetting is out of the box stock, haven't hooked up the wideband to change the main jets. idle is awesome, way better than the stock Hitachi was. even better than my old single 40dcoe was as well.

 

have the stock exhaust resonator in place till i can afford to remove it, so its choking the engine, hence the secondaries wired shut.

 

accell HEI module in aluminum sealed enclosure that acts as the heatsink hooked to a oem magnetic pickup distributor. msd blaster 2 coil.

 

intake stuff is all off the self spectre stuff from oreillys / summit racing. nothing trick about. just welded the appropriate angled tubing from 4inch exhaust steel tubing.

 

funnel - http://www.summitracing.com/parts/SPE-9789/

inline air filter - http://www.summitracing.com/parts/SPE-9831/

carb hat - http://www.summitracing.com/parts/SPE-9849/

 

used a solid rod of stainless for the linkage and used a threaded female ball stud from the end of a trunk lift support for the pedal and the spherical rod end for the carb side.

 

 

this is a video i did before i even adjusted the idle mix or speed, and it had a vacuum leak at the time . i have since foudn and sealed it... throttle response sounds crappy but its actually very crisp.

 

fan clutches suuuuck....

 

<iframe width="560" height="315" src="http://www.youtube.com/embed/c-73nSZ_A4w" frameborder="0" allowfullscreen></iframe>

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I remember the 'Dual Plane' Offys back in the day. Now it may mean something different today but... The runners were split lengthwise with a smaller roughly D shaped upper and a much larger D shaped lower half. The uppers were all fed by the primary or primaries in the case of a 4 bbl. The secondaries were fed through the bottom larger port. In theory the smaller port kept the primary air moving faster than in a huge port for quick throttle response with high overlap cams. The secondary was larger for full throttle.

The theory may work for the manifold but the smaller port dumps into the large port at the head and much of the velocity is lost. I never cared for them.

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i dont have any pictures straight on showing the divider, but yes, the runners are different sizes. the plenum on the engine side are smaller runners to keep velocity up ont he primary barrels and the master cylinder side plenum is larger runners. i had to create and waterjet out that new aluminum plate to rotate the carb 90 degrees to kept the linkage inline and fuel bowels not hit the valve cover. so the dual plenum doesnt really work for me but it runs and idles great regardless...

 

as far as black plugs not sure. havnt hooked the wideband back up to check the jetting but setting the idle mix and speed by vacuum has given great results.

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