Injector bungs on Edelbrock 2115 and 4.9 sequential injection? And budget build Questions

Discussion in 'Big Block Cadillacs' started by CadVetteStang, Nov 22, 2019.

  1. CadVetteStang

    CadVetteStang Member

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    Need advice from those who have been there and done that. First, I'll ramble a bit, then ask questions.... here we go....

    I'm very close to getting the base model 91 Corvette of my dreams and as soon as I do, I'll start collecting the go-fast-parts for the Caddy 500 build.

    The first of the parts collection will involve the intake and fuel injection system.

    Years ago, I think it was MTS (with original owner) who offered the 2115 intake with added injector bungs, so I know it can be done and has been done, but I've never heard feedback about how well it worked or if there were any problems with the installation requiring a labor intensive buildup of material to prevent cracks and leaks.

    The budget build will be for torque and fuel economy. I'm looking at a 4500-4800 RPM motor targeting 600 lbs. of torque and 450-500 hp. Because of the low RPM requirements, I think the 2115's air flow will be sufficient and with the aluminum intake, the motor weight and physical dimensions will almost be identical to the Lotus 350's in the ZR1.

    I might initiate the swap by using the Vette's ecm to control the engine with its batch fire injection, but because of my low RPM plans and desire for fuel economy, I'd love to adapt the sequential injection used on the 4.9 Caddys. They also have a very similar RPM operating range as my planned swap.

    In the past, I used a 368 distributor with the guts swapped from an HT4100 when I put a 472 into my 82 Eldo, so I know that the distributor is the easy part of adding injection to the 500. Whether it's the Vette or Caddy computer, the same distributor will work.

    The throttle body is another issue. For the Vette's horizontal TPI, I can upsize with a salvage yard swap that has 750CFM. I don't see the need for more air with my intended RPMs, but if it's not enough, 1,000 CFM TBI's are available.

    If I go with the 4.9's vertical TBI setup, I already have a 750 CFM Holley tbi that I can put the Caddy's idle control motor on (and remove the injectors).

    Keeping my RPM range and power goals in mind, I already have a 368's TBI intake. I don't know if they have enough meat for the injector bung installation and don't know if port-matching would enable adequate air flow. I would not want that to be the choke of the engine's potential. Who has experience with these?

    Is an MTS #5 or MTS #10 cam a better match for this build? I may have to go with a generic re-grind, but I want to know what lift and duration target to look for.

    Also, there are cheaper 1.6 ratio roller rockers on Ebay. What effect will they have in comparison to the expensive 1.7 MTS roller rockers?

    I already have a 70 model 500 block bored .030 and would really like to put an off ground crank with Eagle 454 rods to make it a 540. How expensive is it to do this mod? If I use that block, I'd have to buy pistons for it anyway.

    Is 10:1 on an injection motor too much for the smaller cam and 87 octane? I'm not going to be using the more expensive fuels for my daily 50 mile commute. 87 without octane booster is my only fuel consideration. Slightly retarded timing worked out well for my carbureted 70 Eldo and it's factory 9.3:1 compression (advertised as 10:1).

    I know, I know, the Megasquirt is going to be suggested. But first, I'm looking at MegaCHEAP. If I can find it in a salvage yard or buy it used, that's the route I need to go. Three 500's and a 472 have been in my garage for 20 years awaiting engine compartment homes and after 20 years of medical bills and low income a $4500 Corvette is still a stretch for me.

    If you have some parts that would fit the build I'm planning, PM me (don't post it here) and I'll get an idea of what's out there for when I have the funds to make a purchase. Hit me with the lowest price you'll take.

    It's going to take a while and the priority won't be there while the Vette's engine is healthy. But I want my engine ready to be installed when the car needs a motor.

    I want all the details worked out well in advance, so what's your experience-based advice?
     
    Last edited: Nov 23, 2019
  2. MIHELA

    MIHELA Active Member

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    They make weld in bungs and fuel rail extrusions to do this pretty easily but to get the injector ports drilled at the right angle would probably require a the services of a machine shop. Top it off one of the myriad aftermarket throttle bodies in place of a carb. Keep in mind the Edelbrock is taller than the stock intake, what's your plan for hood clearance?
     
  3. CadVetteStang

    CadVetteStang Member

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    There are several bolt-ons that look good on the C4 Corvette hood if that becomes an issue, but ive seen a few 454 swaps with carbs and air cleaners that fit under the factory hood.

    I have a tbi if I have to go that route, but I'm really trying to go with an 8 injector setup.

    Drilling at a machine shop is what I had planned to spend the money on. I can get a welding school to do the installation for free after that.
     
  4. MIHELA

    MIHELA Active Member

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    Something like this for rails. You cut them with a special bit where you want the injectors to seat. Tap the ends for AN fittings for feed and return. Then mount them up and have some basic brackets welded up to keep them seated.
    http://www.rossmachineracing.com/dash10.html
    https://www.ebay.com/itm/14mm-Bosch...717854?hash=item3d914c8b9e:g:aX8AAOSwImRYLwUK

    You want as much cam as you can get from what I've heard. I suppose for fuel economy reasons maybe a 10EZ? The MTS5 is a little wimpy.
    Don't buy the Ebay rockers.
     
    CadVetteStang likes this.
  5. Cadillac Kid 1

    Cadillac Kid 1 Well-Known Member

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    Have you thought about using a 76 FI intake and fuel rails? It sits lower than a 2115 and the injector holes are in the correct location.
    Greg Surfas
    If you are interested I have a complete 76 FI system including powder coated intake, fuel rails, injectors throttle body and all the wiring as well as the FI distributor.
    Interested? PM me
     
  6. CadVetteStang

    CadVetteStang Member

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    Thanks, I have thought about using the 76 FI intake; it would be a cheaper and easier way to initiate the swap. However, I do want to cut the 50 lbs. of weight off of the engine, as the car will be used for occasional autocross.

    However, the factory injector angle is perfect. I could use the factory intake as a starting point for the swap and then later as a guide for the machine shop to mod the 2115. And I could keep and use the factory fuel rail. PM will be sent, soon.

    I could move the battery to the back to offset the weight and be good for a while.

    If I pick up a set of aluminum heads at a swap meet for a bargain, then problem solved; I could keep the factory intake.
     
  7. CadVetteStang

    CadVetteStang Member

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    Thanks for that information. I had been thinking about a fuel rail kit for the 454 or 460, but the injector spacers are probably not in the optimal position.
     

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