Okay.. I have a Gen IV 5.3L engine that was pulled from a wrecked 06 Suburban. It has 243 heads, full floating rods, and AFM/DOD.. I want to convert this block, or delete, the AFM/DOD.

My plan is to use this block with a 411 PCM in a 1969 Pontiac GTO. Here are the changes that I think need to be done;
* Replace reluctor ring on crank with a 24 tooth (currently has 58)
* Plug the holes in the valley by tapping & inserting thread-in sealing plugs

This engine came with FLAT top pistons. I've been told that the Gen IV 5.3L engines could have come with flat tops. Is that true?

Also, is it worth the time & effort to convert this block over, or should I just sell it and start with a Gen III block? I have several Gen III motors here already. The only reason I got this Gen IV engine is because it was low mileage-84K on the odometer, and I paid $150 but had to pull it myself. So, I spent about 3 hours with a Sawzall, engine puller, and various air tools getting it out. I have the engine torn down and the cylinders are PERFECT. The piston skirts are coated and the coating is still perfect as well. There are no ridges, scratches, or other issues with the block. I used an inside bore gauge and find less than .002" taper from top of cylinder to bottom. The cam DOD/AFM has no damage, the lifters are good, even the cam bearings are good! My thought was to re-ring it, new crank/rod/cam bearings, change reluctor ring, small cam (.500" lift/212 duration) and throw it into the GTO. IF it's not too hard deleting the AFM/DOD stuff anyway.

Your advise is appreciated. Or, I could just sell the Gen 4 block, crank, cam, valley cover, lifters to someone who needs it. I'm keeping the 243 heads, and full-floater rods.

 

Gen IV 5.3's came with flat tops to increase compression with the 243/799 heads they also came with.
Keep the Gen IV block, and block the risers.
If you have the crank out, changing the reluctor is no big deal if you have the jig to properly locate the reluctor.

 

Thank you for the information. Other than the feed holes in the valley, are there other things that need to be plugged to allow this block to work?

I will let my machine shop change out the reluctor ring-and tack weld it in place once installed. Or, they may have a std/std Gen III crank to swap with me. I will have to ask them if the balance is the same between Gen 3 & 4. Yes, this engine had flat tops and 243 heads. It might have been a later vehicle.. I did not check VIN.. Just saw the electric cooling fans, big 145 amp alternator, and jumped on it assuming it was at least 06..

 

Lingenfelter has a rivet kit with installer tool and rivets that eliminates drilling and tapping. Load rivet tool, insert into riser, pop the rivet, and DONE.