I say fix the FI. Start with this link:
914 D-Jetronic Parts and Troubleshooting It is possible to remove the computer connector and proble your components with an OHM meter. NEVER probe the computer with an OHM meter. Use this as a reference of what you are probing. You must down load the word doc.
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once the FI is running well you will be pleased and have that $700 in the bank.
The stock type IV cam does not work well with carbs.
Slugish acceleration can be a faulty TPS. Also check the FI trigger points. CHT both hot and cold. Temp Sensor 2 does not do a lot. Besure the MPS holds vacuum.