We are "getting there" but it is a slow process

Building a 572ci Mopar Wedge Motor for Project Top Dragster


I came to a conclusion this month when I sat down to write the update on converting our Super Comp / Quick Rod dragster into a dragster that could compete in Top Dragster, Quick 16 and be one of the faster cars in local bracket races. The conclusion is: I am beginning to understand why places like Reher-Morrison, Huntsville Engine, Shafiroff Race Engines and many other engine shops are doing so well. Getting parts ordered and actually delivered is almost a full-time job. All the engine parts are now sitting at Roeder Performance Machine and Jay started the assembly process this morning.

The main changes to the engine include boring it out from the 4.380" to 4.500". That bore size and the 4.500" stroke give us 572 cubic inches. Remember this is a Mopar engine so every item has to be special ordered. There are no "shelf pistons" or ring sets. We decided to go with CP Pistons for the custom ordered pistons, pins and ring package. They were great to work with, got us the pistons in about eight weeks and they are an exceptional piece of work. As most of you know I am NOT an engine builder. I have built them before for my other cars but I wanted a pro to do this one. The engine started out as the Indy Cylinder Head Bracket Master 540". It never failed me and we won a lot of races with that engine. It was time for a serious rebuild and that is what we are doing.

The Project 4-Link Mopar Mega-Block in the honing tank with the torque plate attached. Jay likes to torque the plate on then let it "set" overnight before honing those cylinders. The results are worth the wait.

The CP Pistons were a design worked out by Jay Roeder and Ric at CP Pistons. Like everyone, I wanted durability and the most horsepower we could get. The piston and pin came back weighing 598 grams which saved us about 60 grams per cylinder compared to the Indy set-up. That is pretty surprising considering the pistons are .120" larger in diameter for the new bore. CP Pistons treated the pistons to some tricks trying to squeeze some more power out of my Mopar. They cut the pistons for a .043" moly top ring and the top ring received their "CP Groove" as well as lateral gas-porting slots. This will let the compressed mixture get behind the ring and actually force it out against the cylinder wall to increase the ring seal.

Close up of the ringlands on the CP Piston shows the "CP Groove" just above the .043" top ring and the small slots are for the "lateral gas porting" option. The second groove is for the specially machined .043" second ring that has the "tapered hook" option and the third ring groove is for the 3mm (smaller than the more common 3/16" oil ring).

The second ring groove is also cut for a .043" ring but CP goes one step further and back-cuts the second ring and machines the ring with an operation called the "tapered hook". This also lets any compression that got past the first ring to actually get behind the "hook" on the second ring and force it our against the cylinder wall for better sealing. The oil ring is a very light tension 3-millimeter setup. Everything in the ring package is about minimizing ring drag and parasitic losses in horsepower caused by rings with too much tension dragging up the cylinder walls. Ric and Jay both knew I ran a Moroso 4-vane vacuum pump and this type of ring setup is almost always used with a vacuum pump to create the best oil control by the ring package and offer the best horsepower.

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