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V8Z running MS


pparaska

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  • 2 weeks later...

Yes. The Hilborn is at a friend's place now to be converted. He has a machine shop, so it'll be easier for him to do than me. Problem is that he moves a bit slow.

 

Recently I've had a noise from the 327 that I haven't been able to trace. Sounds like valvetrain. I found 3 pushrods with broken off ends (pressed end 3-piece type junk). Replaced all the pushrods, but the noise is still there. The outer springs look o.k., as do the retainers, locks, the valves don't stick. It might be bad inners (I doubt it), a slightly wiped cam, the gear drive (likely), or who knows what. I may take the time to swap a timing chain set onto the engine to see if that's it, but I'm now working on making my 406 shortblock into a longblock to be able to swap it in soon, so I've about given up on the oil burning 327 for now. The upshot is that now I'm moving on getting the 406 in and sorted so that I can have it at Watkins Glen in mid-August for the ZCCA convention. I think I can make it...

 

For induction on the 406, I'll put the Holley Dual plane (PN300-36) with the 700cfm tbi that are on the 327 on the 406 first. I can swap the 65 lb/hr injectors out for 85s that I have that should feed it fine, but the flow probably won't be there to serve the 406 anyway.

 

I have an intermediate intake setup that should feed the fuel and air adequately. I just need to make some adapters for the throttle bodies and linkage, and a few wiring changes. It's an Offenhauser copy of the 69 Z/28 Cross Ram manifold: http://www.camaros.org/crossram.shtml

 

crossram-offy-iso-42p.jpg

 

And I have 2 Holley 670 cfm 2bbl throttle bodies to put in place of the 2 4bbl carbs. They have 85 lb/hr injectors in them. They flow about 570cfm at 1.5Hg, which is how carbs are rated, instead of the 3"Hg that the 670cfm is rated by.

 

That should be plenty of flow and fuel for the 406, not to mention looking a bit different than the typical single 4 bbl carb under the hood! The large plenum and large, long runners in the Offenhauser manifold ought to provide great midrange on the 406. Mixture distribution may be a problem, as it was for the original Z/28 designs with 2 carbs, but the Offenhauser manifold is a copy of the final design of the GM cross ram where they had worked out most of the mixture issues. Putting TBI's on maychange that a bit, but it may help also.

 

The two 2" throttle plates line up almost perfectly with the smaller 4150 opening(s) in the dual 4bbl top plate for the Offenhauser manifold, if you turn them 45 degrees. Holley makes an adapter to put the large 2bbl TBI on a 4150 manifold, but it tapers the opening down going from the 2bbl to the 4bbl, since they keep the throttle shaft angles the same. I've eyeballed it and it looks like some thin (3/8") AL plates with the 4bbl bolt pattern, held down with flathead bolts into the manifold top, and nut-serts for the 3 (on each TBI) bolts to hold the TBI down will do it. I mocked this up on the 327 while the intake was off a few weeks ago and there's about 6" from the forward edge of the forward carb mounting pad to the hood. The TBI body is very short, about 2". I should have room for two drop base 10" or 11" air filters on top of the TBIs and still clear the hood. I hope to plumb cool air to these.

 

I'll just use the TPS, MAT, and IAC off of one TBIs to send to the the MegaSquirt, and have one of the injectors on one TBI connected in parallel with one on the other TBI, and likewise for the other pair of injectors, and then run alternating squirts like I am now.

 

The Hilborn, that probably won't happen for quite a while - all depends on when I get it back!

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Angle mill the manifold ends, stick in a spacer, and run your port injectors up into the cross ram instead of down the back of the valve.

 

Should be able to "hide" the injectors, and REALLY make some people scratch their heads when they look at your setup...

 

If you really get sneaky, I wonder how the injectors would hold up UNDER the manifold, like some of those old Cheater NOS systems...

 

Muahahaha!

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Angle mill the manifold ends, stick in a spacer, and run your port injectors up into the cross ram instead of down the back of the valve.

 

When I first bought this manifold, the idea was to put the injectors in the runners under the lid (well as much as possible). I like the idea of sticking them in the valley under the manifold also - I don't know how long they'd live there - even if you shielded them from the hot oil bath...

 

Should be able to "hide" the injectors, and REALLY make some people scratch their heads when they look at your setup...

 

If you really get sneaky, I wonder how the injectors would hold up UNDER the manifold, like some of those old Cheater NOS systems...

Muahahaha!

 

Yeah, the plan at that point was to get two 600 cfm Holley carbs and just use them as air doors.

 

Then I decided to just use TBIs and maybe take a advantage of the heat of evaporation of the fuel in the plenum. I dunno if that will have any effect, but once the fuel comes out of the TBI injectors, it collects on the throttle plates and gets sheared off under them. Still droplets at that point, so you might get some mixture cooling if the fuel was to turn to vapor in the plenum.

 

The Hilborn is what I ultimately want - the best throttle response, and great midrange and top end. Plus the "not just another 4bbl on a manifold" impact. The idea is to build 5 sides of a airbox on the injector manifold, using the hood as the top 6th side of the rectangular box. Then vent that to either the cowl with a filter setup in the cowl area, or run tubing forward infront of the radiator with filter(s) there. Pop the hood and you see the injectors and short stacks. I have a set of these that will fit once I cut them down just a bit:

00_12_sb.JPG

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=4559227973&category=6755&sspagename=WDVW

I'll cut them at an angle on the bottom so they don't interfere with each other. Hopefully that won't hose up the flow properties.

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yeah, I like those funnels.

Gaaaaaarrrrrgh....

 

Well, like the guys with the 32 Coupes adn Moon Manifolds with Strombergs, just gut those floatbowls, fire the injectors under the throttle plates in a spacer plate, and run the wires for the injectors into the folatbowls through a vacuum tube...

 

Hell, now those guys with the Moon Manifolds can actually BUY a casting of a Stromberg "replica" specifically cast to hide injectors in the float bowls! Lucky Bastards!

 

 

Then again, you can always find and old Inglese Manifold and swap on 48IDA ITBs....

 

I have an old "Manifold Destiny" ad from a speed mag on the wall out in the shed showing that setup in black and white. Probably been hanging there for close to 20 years now... I know what you mean about that look of two rows of four!

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