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I'm having the crank of my 401 off center ground to accept a 2.1 inch sbc 6 in rod, should get about 3.817 inch stroke. Plan to use a Wisco piston, anyone else tried this? Will have to remove about 4 - 6 cc from combustion chamber to keep compression ratio down to 9.3:1. Any thoughts?
Yes the pistons are forged. I am going to install the valley oil mod. There is a really good machinist here in Great Falls, MT. He has built several engines for tractor pull comps when he was in Ioha.
A write up sounds like a great idea, could prevent others from making a few of the mistakes I made in finding and purchasing an engine (fortunatly very little $ involved, mostly time). If there is a moderator reading, how and where would you like to see this? I've learned a lot about engine geometry researching a rod/piston combo, cross sectioned a head to figure combustion chamber modification, and a few other things for this build. Could post pics also. Please point me in the right direction. Does this have a spell check function?
I've read you could do that using SBC rods and 400 pistons, don't know anymore then that other then I'm looking at a similar project with 4.150 stroke and 4.374 sleeves for 500CI. I guess it's workable.
I looked at the idea of sbc 400 pistons. Several problems, two of the most significant are: compression height is wrong and valve pocket angles are wrong. I called Wisco and Ross and both said pretty much the same thing. Also the 4.165 bore considered, with a 4.125 400 piston dictates for minor .020 bore on the 4.165 = 4.185. The 4.125 at .060 over is the only real possibility. But, considering the other problems, this still won't work. Another thing to consider is the clearance under the piston for the end of the connecting rod. The standard sbc dish is not big enough for the 58cc AMC heads. To get a 9.3:1 compression ratio, the piston dish needs to be 37cc. (I know there is a little room if head gaket thickness is adjusted and there is some room to work with quench) There is not enough material there for such a big dish. Combustion chambers must be opened up 4 tp 6cc to keep the piston dish at no more than 33cc and that is on the edge. One advantage of using a custom piston, is the ability to select a more efficient combustion shape. The machinist has ideas for this I'm not up on yet. As I get more info I'll post.
Here is a question. Is there a production head that will fit the 71 - 78 AMC 360/401 (omit 304 to avoid valve size issue) with a bigger combustion chamber, say 64 or larger cc? I'm not aware of one.
20 May 05. The Edelbrock aluminum head is also a 58cc combustion chamber, stock valve size. I think Indy makes an aluminum AMC head with a 62cc combustion chamber. Very expensive, intended for high rpm applications.
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