Hey Bob,,, not sure if you remember tuning my engines, they made 400hp/425tq,,,, similar builds to Captain YARRR,,,, do you think we would have to retune the ecm to replace stock throttle body with the Holley throttle body

Probably not. I generally tune them a little on the rich side so a small increase in airflow most likely won't cause it to be too lean.
Obviously checking the A/F ratio is the only way to be sure. I tested a 1100 cfm throttle body on CaptYarr's engine. It didn't affect the tune much but definitely made more power. Seems like it was 10-15 hp increase.

Bob

Thanks Bob ,,, didn't know you retired ,,, hate not having a go to guy that doesn't mind working with SBC. Sure hope we can message you sometimes with questions

I built a shop at my house and kept my dyno. I will still be doing some projects...just only things I want to work on.

Bob

I would think the drought hurt you as it was bad here to. Now we are dealing with lakes still closed because of flooding. It has hurt me as well.

You are absolutely correct. It's been a downhill battle since the financial crunch, then historic drought. We had an opportunity to sell our building at a good price so all worked out well. I opened that business after I retired from a real "paying" job in 2000. Now I'm just going to play and work on a few performance jobs of my choosing.

Bob

Will add about MPI / EFI sensors as a lot of problems can be self inflicted - corrosion, poor connections especially at the battery and or starter, improper size wiring and cables, also poor grounds especially back side of engine, also weak batteries, low voltage and or bad cells plus that causes a lot of stress on the alternator along with the starter. Dampness in the engine compartment, Vibration and heat / overheat is a big killer.

Killers also for sensors can be RFI related and for the water pressure sensors, the power steering cooler is not grounded properly ( heavy black epoxy paint ) . FYI

Bob and Capt Yarr, did the exhaust matter much in this build? I understand the internal shape of the glm exh manifolds directs the gases, no problem there. But I wonder how much the ss risers matter? Are they superior for flow or against reversion due to some design element?

On edit, nevermind. I went poking around at the beginning of the thread and found a pic. I didn't know which risers you meant ti I looked at the pic.

I'd be interested to know where the cam is clocked though. Are you able to share the intake centerline that was used?

Well...
Its been 3 years since this great thread was alive!
What have we learned about the 6.2 MPIs that can help with a new 383 build now?