92 merc marquis

vigilant1 opined in news: snipped-for-privacy@comcast.com:

No... dont even think about it.. this is one of those "if you have to ask, you cant afford it" deals.

But in this case the saying applies to the details of the job... the whole powertrain is run by the engine computer and you wouldnt likely EVER get it to run correctly... the project would cost more than an engine replace.

These engines are CHEAP at wrecking yards

I agree with Backyard. Get another 4.6 from a junkyard and drop it in. I have had many Ford V-8's - I really like the way the 4.6L works in my Crown Vic. The 429 is completely different - you'd spend a lot and prolly never get it quite right.

PoD

If you wanted more power you may be able to use the dohc 4.6L used in the mustang mach1 and mercury marauder, The AOD tranny in a 92 merc might be severely taxed with that powerplant however.

You are best off to replace the engine with another like it. There have been several 4.6L blocks with different starter patterns and other features that pretty well lock you into one or two choices. The problem with the 429 swap is that not event the bolts are interchangeable. You have to swap out the trans, the mounts, the wiring and plumbing assuming it will even fit under the hood of the GM. Then you get to try to figure out how to make it run right. And, of course, you have the extra weight on the front suspension to deal with which will require even more mods. Of course, if you have cubic money and lots of spare time, the swap could be rather interesting.