Carb or FI new install
 

OK. I got my engine back from the machine shop. Once it is installed I'm trying to decide if I put the carb back on until I get it up and running or should I go ahead and put on the FiTech FI. The carb ran great for a carb. Just the cold start issues etc... My concern is I am using a different intake. Would that make much difference to the carb? I don't want to bite off too much at once.

Put on that FiTech, if you have everything that's needed.

Think about this, does it have a warranty, and how long is the warranty period?

You want to find out ASAP that there aren't any issues with it, while you have warranty.

Keep the carb as a back up.

Just bought it Dec. 28. I will still need the fuel pump kit. Just that the carb is a known entity while the FI isn't. I don't want to be cranking over a new engine and it not run because of a new FI that I don't have right. hmmmm...decisions decisions..

Use known components to fire a new engine so you know it will immediately start and run. If you don't get immediate engine start on a new engine, you can flatten a cam PDQ...

Lars

put the carb on and get the motor broken in. You still have a lot to buy and modify for FI. You need to buy the command center and wiring plus plumbing it. You need to drill and weld a bung onto your exhaust system. You'll need to install everything. That can take time and depending on what they used to lube the cam you may not want to wait to long to break it in.

Depending on the intake you can run the carb on any intake that the FI mounts to. Most people recommend dual planes for street use/ RPM vs torque. And the more I see about the FI style carb units they like single planes.

What intake were you considering for the fueli injection?

I recommend a single plane intake if you do decide to go FI. The 180 degree firing order that helps a carb signal is not needed and you can cause distribution problems running a dual plane......
Fuel is introduced rather than drawn and acts differently.....a single plane helps even out cylinders.

Jebby

That totally sucks. I sold my single plane and bought a dual plane. Maybe I can swap it.

Put the carb back on get the choke working if it has one.
EFI is great for quick cold starts and very hot weather (re starts), altitutde changes etc but really for the average weekend toy I think its a waste unless you just have to have it.
A well dialed in Edelbrock, Qjet, Holley is every day reliable, never had to touch any of the ones I DD back in the 80s/90s just change theoil and I pounded the daylights out of them not a single hicuup.
Current 850 is no different.

If anything, I would say a divided plenum messes with EFI systems not built to use one. GM ran a dual plane with a divided plenum on all their TBI engines just fine but the GM TBI was built with passageways to measure vacuum from both sides of the intake.


At any rate, get it running with the carb and then go from there.

I agree with everyone who says break it in with the carb, THEN switch to EFI.

I'm dealing with a rebuild bottom-end, rebuilt top-end, AND new EFI system and the list of things I have to validate and test and do prior to the first startup to ensure that it will PROBABLY run good enough to beat on it to get the rings to seat properly is pretty onerous.
Reduce that list to initial startup and break-in and save the EFI for after break-in.


Adam

Flat tappet or roller cam? FWIW, I started and broke my engine in with a newly installed fitech without problems. Just make doubly sure it's right! If using a flat tappet cam then it might be sensible to use the carb, one less thing to worry about. As for the dual plane, give it a try, I'm using a Performer RPM because it's what I had, and it works great.