When converting to EFI with fuel and timing control the vacuum adv makes no difference. It's only there to maintain the stock appearance. For carb use it's always good to run it on a daily driver.
The 4 pin GM module is good for an electronic conversion for use with a carb. For EFI it needs to be a 7 or 8 pin module to allow timing control. Then the mech and vac adv is locked out.
Hot Rod has made some interesting remarks and I would like to have a new thread to discuss them vice going off topic here.
I've done a lot of research on siamese ports and would like to hear more on the subject.
TBI as a "Band-aid", not exactly how I remember it, but it works quite well for our 50+ year old engines that were designed prior to a concern for efficiency. Much better than a carb.
I have done dual 1bbl TBI on a stovebolt. Here's a link with pics.
Dual 1bbl TBI on a 261 Single TBI with DIS-distributor less ignition on a 1275 mini.
Dual SUs converted to dual injectors in the SUs on a 59 Triumph.
And now converting a pair of dual SUs to injection for my mini.
The IH 6 is almost a mirror image of the Stovebolt 6.
I have run 1 and 2bbl TBI on it.
Working on a MPFI system for it now and already have the parts side worked out but debating on making my own log manifold or using the stock one. But anything I do for it should cross right over to the Stovebolt.
The price point or ROI-return on investment goes way off when you start talking MPFI over TBI on these engines.
But it could be another good talking point for another thread.
The whole point is to make them a more efficient and reliable driver so they don't set in the driveway.
Having retrofitted TBI and MPFI on these old engines, my personal experience is the only real thing you gain with MPFI is the shock and awe or wow factor when you pop the hood to show your buddy.
Nothing wrong with that...I have MPFI on 2 of my IHs.
