And the 4.375" stroke, 6.635" (BB Chevy journal) option:

CWmax = 2(Rod - Stroke/2 - Pin/2 - Pthick - Clearance)
For example:

CWmax = 2(6.635 - 4.375/2 - 0.990/2 - 0.180 - 0.60)
CWmax = 2(6.635 - 2.188 - 0.495 - 0.180 - 0.060 )
CWmax = 7.42" dia

The dia of the "cam cut" on my Callies 4.25" stroke crank was 7.32", with the rest of the counterweight larger. So you could design the piston with more meat, if desired (.220 vs .180)

My old pistons were 1.258 compression height with the 6.535 rods and 4.375 crank. Him wanting a 4.5 crank and his current rods 6.575 will give him a 1.155 compresion height. With alot less piston skirt to support at bdc from to short a rod letting the piston stick out at the bottom. The only way I could see him going with the 4.5 stroke is to get a longer rod at least a 6.635 which would give him a 1.095 compression height. With my 6.7 rod and 4.375 stroke I have a 1.093 compression height and the piston skirts are the same length. I am sure the engine will run with your current rods and the 4.5 stroke but with the pistons rocking at bottom you will eather have to rering it or get new pistons from time to time if they are out of shape from the rocking.

Thanks 440Jim,I have CP pistons now but was thinking about using Diamonds with this build.Now I will be checking the thickness of the pin boss when making my decision on which piston to use.Thanks Again!

Thanks Twin Turbo Mower, I do not want the pistons coming out the bottom of the bore far enough to cause a problem either. All of this is some very valuable information.Thanks again!

PS I am going to have to really do my home-work to stay on top of this build!

I used the diamond pistons both times. With the 6.535 rod I had to have the counter weights turned to clear the piston. I probably could have gotten away with it fine if I used the longer rod to begin with. The crank is a eagle crank with 440 mains and counter weights. The counter weights were turned down the the standard low deck size.

You mopar people crack me up!

Run titanium intakes valves, I ordered Victory intakes for my friend's B1 engine. They were really nice. I ordered him Isky Red Zone EZX roll lifters also, we will see how they go.

I too order a set of the isky redzone ez's a few weeks ago. Regular isky redzones are about 950, the solid busing option cost around 1350. I ordered the set with the offset intakes for my 572-13 heads. My old redzones were std seat location, that was with my 440-1 heads then. I would have just sent my old redzones in to get the solid bushing option but he said I had to order new ones since the could not change the seat location.

You are NOT loosing any HP on a 4.375 stroke compair to a 4.500,,, you got the same mabey moore but in a different rpm range.
K1 4,375 stroke with Chevy BB rod journal, the you have allot off rods to pick from.
4,500 stroke get you to short rods,,,,

I forgot to ask has you block been clearenced at the bottom of the bores where the main webbing is? If it is still square then you might have to do some grinding to clear the skirts of the pistons also.

Quote:

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1. Indy Maxx Aluminum Block finished deck height 9.965

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You didn't say, but unless you have a different INDY Maxx block than I have, there is no oiling to the lifter bores...so no pushrod oiling to the rockers is possible.

Yes my block came from Indy stroke clearance.

I went out and miked the pin boss on the CP they were .180. I guess my Caliper's are both in my box at work. So I had to measure the over all height of piston with the tape. It measured 2 7/16" so maybe close to 2.625. I will go over to the shop and bring one of my caliper's back to the shop beside the house where it belongs and get a more accurate measurement. But if I change the stroke will have to change the pistons,I have been doing this for 20+ years and never worried about anything other than the compression height.

I know this is a dumb question,but does it matter how long or short the piston skirt is? If it doesn't a shorter piston skirt might be the answer? Thanks again everyone for all the great help!

Currently my INDY Maxx has a Crower 4.15 crank with 6.570 BME rods and Wiseco pistons (this was an INDY combo at one time). Bob weight was 2144 gms.

I'm switching to a 4.15 K1 crank with K1 6.535 rods and an off the shelf ROSS piston. I had Brian at IMM(OU812) cam grind the counterweights for piston clearance. The bob weight with this combo comes in at 2163 gms, slightly more the BME AL rod combo.

Thanks again Twin Turbo Mower, I was hoping maybe getting the piston skirts as short as possible would minimized the amount that comes out of the bottom of the bore. I saw some real short pistons used in a Pro-Mod 760 or 780 cu in chevy engine,but I guess even in the bore the piston can still rock.

MRMOPAR at present my block does not oil through the push rods,but it can be converted over to oil through them. Just trying to decide if it is something I need to do,its not cheap time you finish with everything that is needed.