The TA reference section has 1.930” compression height for the 401/425 and 1.925” for the 364. They had 10.025 for the 401/425 deck height, but the 364 was incomplete for deck height. I’m thinking now that the 364 cylinders may be too short for the extra stroke. The deck height is a quarter inch shorter then the 401 and the 401 stroke is a quarter inch more. This means the pistons have come a quarter inch further to the inside of the engine because of the shorter deck height of the 364 and the extra stroke of the 401 crank. So, maybe a short skirt custom piston with .100" less compression height and a stock 364 rod. I am not sure if you would interfere with the rings putting the pin .250” further up the piston for a stock 401 rod? Then we still don't know if the bottom of the 364 cylinders are extended further into the bottom of the short block compared to the 401 or if there would be interference with the crank or rods with the cylinders or block. You could experiment with a 401 crank in a 364 using a 364 rod and piston. You would just have to remember the pistons would be .125" or so inboard with the correct compression height. No matter what, this is going to be a big project compared to assembling a standard 401 with off the shelf parts. Cheryl
Babeola, let me throw this stuff at you. if 364 rod is 6.10 and 401 rod is 6.22 both with same pin height 6.22-6.10=.120 would that not make the 364 block only about an 1/8 inch shorter ? on moving the pin higher we went from 1.93 to 1.64 = 290 thousand higher on a 425, shouldn't be a problem on a 364 going as high as 250 thousand. on a shorter lighter pistons the skirts would be a lot shorter shouldn't be a problem . your right ,would need to mock it up and check it. also would you need a certain year 401 crank to match up to a 364 flex plate flywheel ? forgot to add the stroke difference in the first question so stroke difference and rod length would that give you difference in block length, really would like the block length so were not guessing, like you said Tom should know
Joe, I had to think about this a bit last night before making my post this this am. You are only using half of the thow to figure out the deck height from the centerline of the crank. That would be an 1/8 of an inch between the 364 and 401 above the crank. Then there is a 1/8 longer stroke below the crank for a total of 1/4 inch stroke difference. Now we are setting the piston top of the 401 stroke in the 364 using rod length in the same position relative to deck as piston top of the 364 stroke in the same engine. If the 364 and 401 pistons tops are both in the same position at the top of the stroke relative to the deck, the 401 piston will travel 1/4 inch frother down the hole then the 364.
I think we can add together a deck height for the 364 within .005" using one assumption. That is the 364 piston top is the same distance from the deck as the 401 piston top is from the deck. Let's assume .055 piston to deck clearance: The 401 deck height equation would be half the 401 stroke (part above the crank centerline) 1.82" + 401 rod length 6.219" + 401 compression height 1.93" + 401 piston top to deck clearance .055 = 10.024". That is within .001" of the known deck height. The 364 deck height equation would be half the 364 stroke 1.695" + 346 rod length 6.1" + 364 compression height 1.925" + 365 piston top to deck clearance .055 = 9.775". If we can rely on our only assumption, the 364 deck is .249" or 1/4" lower then the 401. Hey Tom, are we there yet? Cheryl
ok ,now we are getting some where. using 401 rods we would need a pin height of 1.725 that's only moving the pin 200 thousands up, no problem there. would put the piston about 10 thousand in the hole.
I believe that the only year 425 that will bolt to the 364 flexplate is a 1963. Any 401 up through '63 should bolt to the 364 plate. You would have to check with Tom Telesco about the balance, though.
