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Crossfire dual carb

Old 04-16-2019, 08:59 PM
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Crossfire dual carb

Hello everyone,
I am new here and have recently purchased a 1983 Z28. The car is very clean but the fuel tank and pump were trash. I have done quite a bit of work to get it running well, but I need more power. I like the crossfire setup but would like to use dual carb on a 383 build with a renegade intake. I want to keep the breather and scoops functional for that nice slow Camaro look lol. Has anyone tried doing dual carbs on the crossfire intake?
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Old 04-16-2019, 09:07 PM
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Re: Crossfire dual carb

I see the other threads on this topic but no one mentions the renegade or Offenhauser intakes
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Old 04-16-2019, 09:17 PM
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Re: Crossfire dual carb

I’m not aware of anyone who has converted the Renegade to carbs. But here’s some trivia for you. The Crossfire intake base reused the 67-69 Z/28 Crossram intake tooling. They had to reduce the size of the of the runners and ports to keep velocity up while using two Iron Duke 175 CFM throttle bodies though. Didn't quite work as well at 4500 rpm as it did with two Holleys at 8000 rpm.

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Old 04-16-2019, 09:30 PM
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Re: Crossfire dual carb

No need to go carb for mild 383-just upgrade the CFI and it will be good enough for a "warm"street 383-if you want "hot"street 383,better to just go carb with a standard manifold.
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Old 04-16-2019, 10:25 PM
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Re: Crossfire dual carb

Idk, but someone should mount 3 bbl TBIs on a V8. Just because. Or, turn a LU5 intake into a wind chime... Wonder if an oldschool crossram intake with two Holley 4bbls would fit under a thirdgen hood, and how far off the hood would be from being able to be made functional... Hmmm...
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Old 04-17-2019, 05:20 PM
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Re: Crossfire dual carb

Originally Posted by Daves83 View Post
I see the other threads on this topic but no one mentions the renegade or Offenhauser intakes
There's several low-profile crossram intakes that were intended for carbs that could be modified for multi-TBI use.
Offenhauser is probably the least expensive other than an OEM Crossfire with a modified top plate. Offy had dual-four, single-four, and three Weber top plates. What is currently available is anyone's guess. Offy hasn't been a "real" company for years if not decades. It seems they produce parts when they have enough orders pre-sold, so inventory is sketchy and back-orders are common.
Edelbrock Smoke-Ram was intended for single-four barrel carb, but of course you could fabricate a different top plate to accept dual fours or dual one-barrel TBIs.
Edelbrock STR (Street Tunnel Ram) was intended for dual fours, would accept dual TBI with adapters or a different top plate

Originally Posted by chazman View Post
Iím not aware of anyone who has converted the Renegade to carbs.
Seems like a waste of a specialized manifold.

Originally Posted by chazman View Post
But hereís some trivia for you. The Crossfire intake base reused the 67-69 Z/28 Crossram intake tooling. They had to reduce the size of the of the runners and ports to keep velocity up while using two Iron Duke 175 CFM throttle bodies though. Didn't quite work as well at 4500 rpm as it did with two Holleys at 8000 rpm.
What tooling? The manifolds are VERY different, not just in runner size but also in terms of EGR. I don't know what would be salvaged from the original crossram tooling to produce the TBI manifold except maybe the aluminum-melting and pouring equipment.

Far as I know, the original crossram was made by Winters. Who made the Crossfire manifold?
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Old 04-17-2019, 05:28 PM
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Re: Crossfire dual carb

Originally Posted by Schurkey View Post
What tooling? The manifolds are VERY different, not just in runner size but also in terms of EGR. I don't know what would be salvaged from the original crossram tooling to produce the TBI manifold except maybe the aluminum-melting and pouring equipment.

Far as I know, the original crossram was made by Winters. Who made the Crossfire manifold?
Don't remember. It was from a book, "Chevy Smallblock" or something like that, where they were interviewing the CFI developers and they stated that GM forced them to reuse the crossram tooling. They went into detail on the air fuel distribution problems that caused them. They also stated that with a little more development they could have fixed it, but they had already moved on to TPI by then.
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Old 04-18-2019, 05:11 PM
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Re: Crossfire dual carb

Compare the "racing" dual-four crossram manifold
http://www.camaros.org/crossram.shtml
http://www.vintagemusclecarparts.com...-302-crossram/




To the emissions-choked dual-TBI "crossfire" manifold:
http://www.technovelocity.com/chevyh...rt_polish.html



There's very little that is the same--from the thermostat housing angle in front, to the overall shape of the top cover, to the EGR in back. I'm having problems finding a photo of the underside of the older crossram, but the way I remember it, it didn't even have an exhaust crossover.

I can't imagine Winters re-using any tooling from the Sixties cross-ram on the TBI cross-ram.
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Old 04-18-2019, 05:22 PM
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Re: Crossfire dual carb

I see a lot of similarities. Furthermore, he also stated that the biggest distribution problems were caused because the front TB was on the passenger side. He said, if they could have done it the other way around, ie., the front TB on the driver's side, they could have solved a lot of air/fuel distribution problems, but they weren't allowed to deviate that far from the old Crossram design. He explained the reasons why, but I can't remember them.

Maybe I'll search for that book and get the engineer's name. It's in my basement in a box somewhere.

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Old 04-18-2019, 05:51 PM
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Re: Crossfire dual carb

I can't believe I found it. The book is: CHEVROLET SMALL-BLOCK V8, by Anthony Young. Really an interesting book.

The engineer is Louis Cuttita. If I'm not mistaken, it was him and his team who quickly hotrodded the LG4 into the L-69.


Standby....
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Old 04-18-2019, 05:58 PM
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Re: Crossfire dual carb





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