using pre86 block with EFI

You may need the EFI heads and intake The block and innards are interchangeable...

I stuck the 1986 Truck EFI parts on a 1982 Bronco motor with the 1982 carburetor heads, works great.

No!

For doesn't/didn't produce any (after 1960 anyway) V-8's with the distributor on the wrong end of the engine.

It will work just fine. Early intakes had more hold down bolts than later onesd. So your heads may have some extra holes. But don't worry about that, everything will bolt up and work just fine. The only issue you may have is the valve covers. The EFI manifold hangs over the valve covers, and tall ones (like "COBRA" style) are too tall, unless you place a spacer between the the upper and lower intakes.

You make that sound like its a bad thing! EFI has its place, but if your going for performance stick with the carb, your wallet will thank you. With a Holley you can change jets when ever you want. With EFI you'll either need a lap top tuning device or take it in and have a new chip burned. Same with the timing curve of the distributor.

As far as the blocks the only difference in the old vs. new is the lifter bore height and real main seal type. The new blocks have a longer lifter bore to allow for the hydro roller lifter. You can get a custom ground cam with a small base circle that will allow you to run the roller lifters but its spendy to go that way. If you stick with a flat tappet cam make sure your firing order matches the computer. The mustang computers use the 351 firing order so you'll need to run a 351 flat tappet cam so that will match up. Also if you stick with a flat tappet cam make sure you don't use a EFI/Roller distributor with its stock cam gear. You'll need to change that out to match the cam other wise one or the other will be chewed up and send nice little chunks of metal all thru your new engine. As for the rear main seal just use what ever matches your block. You'll need to watch your balancer choice. First it will need to match the crank imbalance which is either 28 or 50 oz. Then it will need to match the front dress your using. If you are using a 50oz crank and an older three bolt pulley set up you may have limited choices to balancers, but they are out there.

As for head there is no real change in those for EFI. Some of the older heads had an extra intake bolt by the water passages, but even the newer carb intakes don't use it.

MadDAWG