Slant 6 4bbl Carb Selection

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michiganpat said:
for what it's worth, if it's primarily a street motor with a mild cam, you may want to even look at the Aussiespeed 2bbl manifold that has a 2300 holley bolt pattern. might work better and give you more efficiency for the street. another consideration would be since a new AVS is $500, for a street driven vehicle, especially since the aussiespeed manifold doesn't have provisions for manifold heat, it might be worth at least looking at the Holley Sniper or similar EFI systems. just food for thought....eventually I'd like to build up my slanty with some head porting and milling, perhaps deck the block to get compression in the 9:1 range, a cam with about [email protected] duration max (likely one of of the two smallest hughes whiplash cams), clifford shorties, and the 2bbl hurricane running either a holley sniper system, or maybe even trying to do MPFI utilizing a late 90's early 2000's truck throttle body (since I have a complete 318 magnum intake sitting on my garage shelf)....
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I have been running a Performer 600 on my 289 and a Performer RPM Airgap manifold. Fuel economy was pretty good with 2.79 rear gears. I am rebuilding the engine and will install the annular boosters from the AVS2 650. The secondaries are where the extra CFM come from.
I think it was The Carburetor Shop website tells that some early Autolite carbs had annular boosters and gave excellent fuel economy. These would be smaller carbs when engine displacements were less. Many 4 barrel carbs give very good fuel economy if you refrain from getting the secondaries open.
 
Since most of the comments have been about cam/carb/exhaust; I would encourage the OP to raise the compression on that engine. RRR built his /6 on a budget and is extremely happy with the performance after raising the compression.
 
michiganpat said:
on your build, is it stock bore/pistons? did you deck the block or cut the head for compression?
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Stock bottom end with a big solid lifter cam. Head cut about .175" (it was an accident, long story). Blueprinted compression was right at 10.5 so I knew I needed a lot of cam so it would run on pump gas. I called Ken Heard at Oregon Cam and we decided on with .465 lift, 250 degrees duration @ .050" ground on 108 lobe separation. I went low lift because I already had valve springs (Comp 942) and I needed to utilize those. The engine turned out much better than I would have imagined. It runs extremely well, even with that rowdy cam. I'm sure the manual transmission and 3.23 gears help, but even still, I think it would be peppy.
 
RustyRatRod said:
Stock bottom end with a big solid lifter cam. Head cut about .175" (it was an accident, long story). Blueprinted compression was right at 10.5 so I knew I needed a lot of cam so it would run on pump gas. I called Ken Heard at Oregon Cam and we decided on with .465 lift, 250 degrees duration @ .050" ground on 108 lobe separation. I went low lift because I already had valve springs (Comp 942) and I needed to utilize those. The engine turned out much better than I would have imagined. It runs extremely well, even with that rowdy cam. I'm sure the manual transmission and 3.23 gears help, but even still, I think it would be peppy.
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thanks for the info, sorry if I hijacked the post....my wish list is to eventually hop up my slant, was figuring rering if the bores look good, one of the 2 smallest hughes cams, cut the head .1" or so, a little bit of bowl work, dunno if I'd go bigger valves or just backcut the stockers, I'd like to go with the aussiespeed 2bbl hurricane manifold and some sort of EFI, whether it's the 2bbl holley sniper, or figure out a controller and doing a port setup utilizing some OEM injectors (I do have 16 5.2L magnum injectors on my shelf) and the 2bbl magnum throttle body I have sitting on the shelf, too...
 
michiganpat said:
thanks for the info, sorry if I hijacked the post....my wish list is to eventually hop up my slant, was figuring rering if the bores look good, one of the 2 smallest hughes cams, cut the head .1" or so, a little bit of bowl work, dunno if I'd go bigger valves or just backcut the stockers, I'd like to go with the aussiespeed 2bbl hurricane manifold and some sort of EFI, whether it's the 2bbl holley sniper, or figure out a controller and doing a port setup utilizing some OEM injectors (I do have 16 5.2L magnum injectors on my shelf) and the 2bbl magnum throttle body I have sitting on the shelf, too...
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I don't think it was a highjack at all. If you want to, why not make a thread and give us some ideas on what you're thinking for your build? That way, we won't have a chance of getting this too far off track. So far, it sounds like you have a solid plan. I'll be looking for your thread and we can bounce some ideas off.
 
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