Ok, i've been trying to decide what to do with my 460? I found a 557 stroker kit on ebay. Would I be stupid if I used the stroker kit with stock heads? What mods should I do to the heads to help this kit perform? Here's the item number 8028971867

 

Stock heads with the smaller ports will only improve your low end torque so I ask what do you plan on doing with the motor? This will decide what heads you.

I did not look at the kit but do your home work as some kits are cheap to buy but cost a fair amount to have a machine shop finish for you like balancing and I have heard of counter weights having to be cut down or something like that.

I am in no way shape or form a stroker expert but have read a few things here and there.

 

As RTM already mentioned there's a lot of hidden expenses with some of the "cheap" kits and I've read about guys spending almost as much in machine work as they did for the rotating assembly. To make that kit perform you'd need your heads fully worked by an expert, like Scott Johnston. I don't know exact prices but you can expect it to run you $1500-$1700 for all the headwork with new valves, springs, rocker studs and all that mess. You'll need at least a 950 cfm carb to feed it so take that into consideration (as well as the extra fuel consumption). You'll need a new intake which will probably need to be ported and matched to those heads and you'll most likely need to go with a roller cam to allow enough air in. Then there's the hardened pushrods, roller rockers and all the other little details. Remember that the engine is an air pump. The larger your displacement the more air you need to be able to feed it via carb, intake, heads and cam. If any one of these is inadequate for the application your performance will suffer greatly. I'm just starting a similar build and I can tell you first hand that the rotating assembly will actually end up being one of the cheaper expenses of a build like this.

 

Some of the more wild stroker kits require clearancing the block - i.e. notching various areas of the inside so that the rods don't hit the inside of the block preventing the engine internals from rotating.

This is a total PITA type of work, not because it's difficult, but because it's time consuming. YOu need a die grinder and a carbide bit (and goggles) and a fair amount of free time.

You grind, then install the rotating assembly, verify clearances, then remove rotating assembly and grind more. Then repeat.

Of course you can pay a shop to do this.

Also verify the stoker kit is balanced. If not, a local shop will have to do this for you unless you have the machinery and experience to do so. Strokers really need to have at least a "reasonable" balance otherwise they rattle themselves apart. Size/weight of the parts as well as higher RPM's usually make balancing more critical. 557cid is pretty big.

If you're serious about a 557 stroker, you might consider a stud girdle, typing the main caps together. This requires decking of the bottom of the block with the main caps installed, so that the girdle can fit tightly and the oil pan underneath that. This will require some fabrication of the oil pickup tube so the end that sits in the oil is in the right place, rather than higher (meaning the factory location + the thickness of the girdle). The girdle I'm using for my 500cid stroker is 1/2" thick 4340N. Stout stuff. If it comes off, it's taking the side of the block with it. Most girdles are thinner, typically 1/4 or 3/8 or thereabouts.

 

I've never ran one of the really big inch kits, but I have built a few 514 CI using the Ford SVT kit, no problems at all. Starting another one now for my Ranchero, heads will be AFR's.... On any stroker kit, balancing the rotating assembly is essential !!!!!