84Z51J

Trying to come up with a parts list to prepare for parallel plumbing and an external regulator for my '84 CFI. Got the regulator/accumulator block-offs covered. Think I've got the routing set, but correct me if I'm wrong:


-Remove all connections. Reroute the stock supply line to the Y-block inlet.


-Run two supply lines (one per TB) from the Y-block outlets to the throttle body inlets.


-Run two return lines (one per TB) from the throttle body outlets to the regulator inlets.


-Connect the regulator outlet to the factory return line.




Simple, right? Now for the trouble. I'm having a hard time finding the right adapter bits to make it all mate up. Here's what I know:


-OEM supply and return lines are 3/8" and 5/16" OD, respectively. They use 5/8-18 and 1/2-20 inverted flare fittings, respectively. I'd like to reuse these & avoid the cost of a flaring kit.


-The Aeromotive 13301 regulator (on-hand) has 3/8 NPT ports all around.


-I can get a Y-block that also has 3/8 NPT ports, or one that accepts -AN fittings.


-I'd love to find a Y-block with 9/16-18 inverted flare inlet port so I could mate it directly to the OEM supply line, but haven't seen any. Next best thing would be a 9/16-18 inverted female to 3/8 NPT male adapter...but also no joy.


-I have also been unsuccessful locating a 3/8 NPT male to 1/2-20 inverted female adapter for the "regulator to OEM return line" connection. Found a part number at https://www.fastenal.com/products/details/440291-131280 ...but they are out-of-stock everywhere.




Is there an easier way? Am I missing the point? I really didn't expect adapter fitting nonsense to hold me back this much, but I must admit trying to convert back and forth between -AN, inverted flare, and NPT is really bringing out my dumb.


Has anyone who has done this project successfully retained the stock lines & fittings, or is it an exercise in futility? Input welcome...school me on fuel plumbing!

blackozvet

have you checked Summit, they have a pretty big range of fittings and adaptors, I bought all my stuff from them to do my single plane conversion.

http://www.summitracing.com/int/sear...illocation=int

corvettenorway

http://www.technovelocity.com/chevyh..._delivery.html

1984Z51auto

You do know that the stock injectors are two different sizes as a result of the stock system having series (not parallel) piping and a fuel pressure drop between the front & rear TBIs, right? So on top of the piping issues you need matched injectors also.

84Z51J

Finally got it figured! Decided to go with -6AN lines & Y-block. Part list with locations:


- [eBay] [TBI regulator block-off plates & gaskets] [x2] (one set per TB)
- [eBay] [80# big block injectors] [x2] (to replace OEM stagger-sized pair)
- [Aeromotive 13301] [Vaccum referenced fuel pressure regulator] [x1] (return side)
- [Russell 650400] [Y-block] [x1] (supply side)
- [Marshall MS00060] [0-60 PSI fuel gage] [x1] (connected to regulator)
- [Russell 661571] [3/8 to 1/8 NPT reducer] [x1] (connects gage to regulator outlet)
- [eBay] [-6AN male/male coupler] [x2] (Y-block outlets)
- [Russell 640610] [-6AN male to 5/8-18 inverted female] [x1] (OEM supply line to Y-block adapter)
- [Russell 640380] [-6AN male to 5/8-18 inverted male] [x4] (TB adapters)
- [Russell 660461] [-6AN male to 3/8 NPT male] [x3] (2x regulator inlets, 1x connected to return adapter)
- [Russell 640600] [-6AN male to 1/2-20 inverted female] [x1] (-6AN to OEM return line adapter)
- [Russell 640001] [-6AN female/female coupler] [x1] (connecting 660461 & 640600)
- [eBay] [3/8 NPT pipe plug] [x1] (extra regulator port)


Includes everything except the hose & ends; will have to mock this all up before I'll know the total length required. Throwing new RHS aluminum heads into the mix; replacement injectors are sized accordingly.


For anyone else considering this project, I did already pick up an extra set of OEM TB fittings:



I plan to swap out the one smaller return fitting on my car and end up with all the same size (M12 x 1.25 to 5/8-18 inverted). Check your shopping list! Corvettenorway's link shows you can remove those OEM conversion fittings entirely and use metric to -AN carb inlet fittings instead...probably easier, but I couldn't find any which would match the rest of my silver-colored fittings

84Z51J

Yep...hence why I'm going to all this trouble to correct that!

84Z51J

Wish I'd seen your post a couple hours ago

corvettenorway

corvettenorway

other than the renegarde,any engine mods ??

84Z51J

Big project in the works. Aside from intake mani swap, just exhaust is done; 3" true dual w/cutouts & OEM mufflers. Slightly upsized radiator from Champion as well.


In the process of adding RHS 180cc/64cc heads, new valvetrain, parallel plumb w/upsized injectors & vaccum referenced regulator, EBL flash ECM, and wideband O2.


Cam/lifter kit & porting will come after I get her running & stable

corvettenorway

sounds like fun and love to se som dyno result

84Z51J

Minor update. Swapped out the 650400 female y-block (which would have required o-ring fittings to seal) for a 650430 male one. Returned the 2x eBay -6AN male-to-male unions I thought I'd need for the y-block outlets. Purchased an additional 640001 -6AN female-to-female union so the now-male y-block inlet will mate with the 640610 -6AN male to 5/8-18 inverted female inlet adapter.

84Z51J

Another update--swapped out MS00060 for MS00030 0-30 PSI gage. I should have done fuel requirement calcs before ordering! Will be running <30 PSI fuel pressure for the foreseeable future (probably ~25), so I may as well have proper resolution