Strked 440 tork monster

[djswwg]

Looking to build a stroked 440 to haul around a 68 Charger. On paper, here's what works. Ross piston with 4.36 bore and 1.471 comp. height; 4.15 stroke crank, 7.1" h-beam rods. If I've done the math properly, a light cut off the block will get 10.625:1 compression with a .020 head gasket. We'll use aluminum heads, 88cc. Has anyone out there done this? Are we going to run into any crank or rod to block clearance problems? Anything else? Any and all input most welcome!!!......djs

[bishop]

If your planning on running alumium heads your going to have to use a head gasket like a fel-pro which is roughly .038 compressed you can't run a steel gasket in between alumium and cast iron.

[sixpackgut]

as far as i know all that needs to be notched out is the bottom of the cylinder bores. i am building one too but i'm in the parts gathering stage and the machinest is in the hospital. bishops post about the head gasket is correct also. you could change to the 84 cc edel head and use the felpro gasket.

[hedgehog]

You will have to notch the cylinders. Also you will have to grind some on the pick up tube boss and if your using a 1/2" pick up tube you will have to heat up a small portion of it and contour it with a hammer to clear the rod. With your combination you will have around .200" quench which is way too much. You need to find a combination that will give you a .040" quench and still maintain the desired compression ratio. A 10.5 or 11:1 engine with .200" quench will not run the way your expecting. I recently built one just like it except i used the 6.860" rod, a KB quench dome piston and closed chamber Edelbrocks. The quench dome ended up being .054" which made it deck high and netted me around 10.5:1. The problem with that is the hemi length rods use a 1.031" pin. So i had to install the larger 440 pin bushing which meant boring the pin ends to accept the larger O.D. bushings. Just costs extra money. Hasn't been raced yet but it runs quite well on the street in front of a 4-speed.

[djswwg]

Hedgehog, if I understand you correctly, the piston is too far down the bore at top dead centre, even though the compression ratio is OK? Please expand on this for me if you can. Anybody else??? I like short piston long rod combo's, am I going overboard here or what??........djs

[hedgehog]

The long rod idea is good but not at the expense of too much quench. The more quench you have the more dead combustion space you have, also less combustion turbulence and a much larger area for the mixture to spread out in which requires more spark advance to get the mixture burnt because of the increased time it takes to cover the chamber. The smaller the combustion space the better. You want a minimum quench distance to squeeze the mixture toward the plug. That large quench area will give you less power, worse mileage and more detonation problems. Just as an example, a 9 or 9.5:1 engine with .040" quench will make more power than a 10 or 10.5:1 engine with .060", .080" or more quench. Thats why ultimately a quench dome piston is the way to go if your looking to minimize quench and maintain a pump gas compression ratio.

[djswwg]

OK I think I'm getting the picture. So it's better to have the piston go up as close to the head as possible (without having interference issues of course) to make maximum power, Right?..djs

[hedgehog]

Yes, quench distance is very important.

[sixpackgut]

hedgehog, what kind of machining process do you use to notch the bottom of the cylinders.

[djswwg]

Thanks hedge, and like spg, I'd like to know how to notch the bores too.........djs

[hedgehog]

Just use a die grinder.

[sixpackgut]

cool, do it myself. thats what i was hoping for but mopar muscle did a stroker buildup on a fast class road runner 2 months ago and it looked like they used a bore bar to do it but it also took a chunk out of the pan rail and i didnt care for that at all. thanks hedgehog.

[DartGT66]

No need to clearance the pan rails. I have used custom pistons with D-shaped dish to get the CR I want and still have a good quench distance with bigger engines & small closed chambers. It's only 100$ or so more than a list set of quality pistons.