five0fm

if ive got a 1.300 compression height pistons with a 4.030 on a 351 block what size rods and what stroke crank do i need to reach 427 cubic inches?

SonicBlueFiveSlow

4.170 crank and 6.125 rods

woodsy

Thats an odd comp height for a 427, but you could make it work with a 6.125 rod this would require you mill the piston. What is the current deck height of the block and will surface and square the deck? (you should) So simple math says half the stroke 4.170/2 = 2.085+1.3+6.125= 9.510 so the piston needs .010 cut off it and if you cut the deck .010 to square it that would mean you need to cut another .010 off the piston to achieve 0 deck. So in short, DEPENDING on the piston skirt design and length you can use a 4.170 crank, 6.125 rod and mil the top of your piston .020 and cut the block.010 and be at 9.49 and 0 deck. What piston is it?

woodsy

I might also add that you need to mock this up before any machine work, especially balancing since the 4.170 crank puts the big end of the rod way up in the cam tunnel you may need to clearance the rod or it will hit the cam, this is rod dependant and cam dependant, but I can tell you a typical I beam with a nut and bolt, 4.170 crank and an XE282HR cam, the big end of the rod hits the cam lobe, thus clearancing needed

five0fm

its currently a 9.5 with a decking, a 4.000 stroke and 6.2 rods....and i rather not mill the pistons..maybe ill go with a 4.100 stroke. so 4.100/2=2.050+1.300+6.100=9.45
im not sure how much was taking off with the decking of the top of my head. but say i did that set up how many cubic inches would i be making?

woodsy

The windsors are supposed to be 9.503 and most times are 9.500 from the factory I doubt taking .003 off the deck got it square, your sure its 9.5? Your going to have cut the piston anyway you slice for cost and ease. Whos piston is it? a 4.00 is used for a 408, a 4.100 for a 418 and the 4.170 for a 427

five0fm

i ment that its a stock block with a decking and i dont know how much they took of the top with the decking. and its an srp piston

woodsy

OK well first you need to know what the deck height is now, before doing any calculations. Either way you cut it, you will be milling the pistons