Stroker Combo's for a 400 and 4.15 Crank....?

[DGrace]

I've searched but can't seem to find what I'm looking for. I downloaded a chart (from Andy F, I think) for a 470 build using a 400 block and 3.91 crank showing the different length rods (Big Block Chevy) and piston combo's but I don't know how to come up with those stats for a 400 block with a 4.15 stroke crank. I looked at 440 Source but they only list one - 500 cubes with a 6.760 rod and it uses a piston that requires oil ring supports and I don't want to do that. Was thinking a shorter rod - 6.535 or 6.385 may work but no idea about the piston possibilities....Any help or resource would be appreciated. Thank you....

 

[66Valiant528]

What is the bore size?

 

[DGrace]

Well, I haven't had the block to the machine shop yet but I think it's a standard bore - guessing .035 over so a 4.375....

 

[67/6barracuda]

DGrace I’m going follow along I’m in the same situation. 400 block standard bore I have the steel eagle 4.150” crank. Headmen b body headers and a edelbrock dual plane intake. I need everything else the rods and pistons likely will be the 440 source stuff. I joined the facebook page 500 inch mopars these guys know their stuff. I had the same concern you do with the short skirt piston and oil support rails. But that’s what makes the build awesome because you have 500ci with half the weight of a 440 piston that revs to 7500rpms. These nuts are running them on the street from 650-800hp. Also follow justMoparJoe YouTube channel look for his playlist for Dave’s big block 500 stroker it’s the same build we are planning he makes some steam with this build. Good luck

 

[67/6barracuda]

Also there are both new edelbrock and trick flows big block heads coming out for 2026 those 295 trick flows are going to be something if it’s in your budget.

 

[MOPARMAGA]

Want a 470.
Either 3.910 stroke crank
Or 440 crank , cut mains, offset rod journal to bbc & cut counter weights
6.700 rod length is what I run, 1.320 ch pistons. 4.375 bore.
If you want a 4.150 stroke crank get one with bbc journals, molnar makes one.

 

[MOPARMAGA]

I've searched but can't seem to find what I'm looking for. I downloaded a chart (from Andy F, I think) for a 470 build using a 400 block and 3.91 crank showing the different length rods (Big Block Chevy) and piston combo's but I don't know how to come up with those stats for a 400 block with a 4.15 stroke crank. I looked at 440 Source but they only list one - 500 cubes with a 6.760 rod and it uses a piston that requires oil ring supports and I don't want to do that. Was thinking a shorter rod - 6.535 or 6.385 may work but no idea about the piston possibilities....Any help or resource would be appreciated. Thank you....

Do you know the math ? If not.... take the stroke length ÷ by 2 add the length of the rod. Then subtract that from 9.980 and you'll get what's left over for piston compression height.
There's not much available with the Chrysler rod journal in terms of rod length & that's typical of 4.150 cranks, bbc journal offset from there is 4.250

 

[Jeremiah (jd)]

I would not be afraid od the 1.120" conpression height piston. A 5.3 LS CH is typically around 1.115-1.35" and they go 200k miles. In addition, the 1.32" CH piston uses oil rail support rings.

 

[DGrace]

DGrace I’m going follow along I’m in the same situation. 400 block standard bore I have the steel eagle 4.150” crank. Headmen b body headers and a edelbrock dual plane intake. I need everything else the rods and pistons likely will be the 440 source stuff. I joined the facebook page 500 inch mopars these guys know their stuff. I had the same concern you do with the short skirt piston and oil support rails. But that’s what makes the build awesome because you have 500ci with half the weight of a 440 piston that revs to 7500rpms. These nuts are running them on the street from 650-800hp. Also follow justMoparJoe YouTube channel look for his playlist for Dave’s big block 500 stroker it’s the same build we are planning he makes some steam with this build. Good luck

Yah, I follow both JustMoparJoe and RustBucketRestos - love their stuff - next level in mho.... I picked up a Molnar 3.91 crank a 6.535 rods for a 470 build but I also have access to a 4.15 crank and was wondering about the possible combo's that are available. My main concern (from what I've read) is that the short skirt piston with the oil ring supports cause "piston slap" which does not seem desirable. I'm no engine builder so I'm trying to do the research before I go any farther. I picked up my TF 240 heads recently (Christmas present to myself) and Harland Sharp rockers so my 400 block will be headed to a machine shop soon - ish. I've been carrying that block around since 1996 and it's long past due for a build.....many roadblocks and detours along the way but LORD willing, this thing will live! Thanks for all the replies..... Not many (as in none) MOPAR friends so not much help or input - you guys and YouTube......

 

[DGrace]

Do you know the math ? If not.... take the stroke length ÷ by 2 add the length of the rod. Then subtract that from 9.980 and you'll get what's left over for piston compression height.
There's not much available with the Chrysler rod journal in terms of rod length & that's typical of 4.150 cranks, bbc journal offset from there is 4.250

No sir, I didn't know the math so thank you. Do piston manufacturers have a tool to plug in your dimensions and list possible candidates? Thank you.

 

[DGrace]

Want a 470.
Either 3.910 stroke crank
Or 440 crank , cut mains, offset rod journal to bbc & cut counter weights
6.700 rod length is what I run, 1.320 ch pistons. 4.375 bore.
If you want a 4.150 stroke crank get one with bbc journals, molnar makes one.

Yes sir, got the parts for a 470 build - Molnar 3.91 crank and 6.535 rods.... just seeing what combo's are available for a 4.15 stroker.....all I really came up with was the 440 Source 500" one. Seems odd (to me anyway) to go to the trouble of making a 4.15 stroke crank (especially for such a seemingly narrow market) and offer very limited rods/pistons that can be used with it? Thank you....

 

[DGrace]

Also there are both new edelbrock and trick flows big block heads coming out for 2026 those 295 trick flows are going to be something if it’s in your budget.

Well, I recently pulled the trigger on TF 240's and they should be able to deal with my intended hp level of around 500.....or so.....plus, I had to sell a kidney to get those.....

 

[DGrace]

DGrace I’m going follow along I’m in the same situation. 400 block standard bore I have the steel eagle 4.150” crank. Headmen b body headers and a edelbrock dual plane intake. I need everything else the rods and pistons likely will be the 440 source stuff. I joined the facebook page 500 inch mopars these guys know their stuff. I had the same concern you do with the short skirt piston and oil support rails. But that’s what makes the build awesome because you have 500ci with half the weight of a 440 piston that revs to 7500rpms. These nuts are running them on the street from 650-800hp. Also follow justMoparJoe YouTube channel look for his playlist for Dave’s big block 500 stroker it’s the same build we are planning he makes some steam with this build. Good luck

I looked at the Eagle kits with the 4.15 crank to see what pistons they use (one said Mahle) but no info..... The pictures showed no oil ring supports required but it may have been a generic photo....? Not overly concerned with being able to reach high rpm's, although the lighter weights would be good.....

 

[MOPARMAGA]

No sir, I didn't know the math so thank you. Do piston manufacturers have a tool to plug in your dimensions and list possible candidates? Thank you.

You could look, but really there's only a few possibilities.

 

[MOPARMAGA]

Well, I recently pulled the trigger on TF 240's and they should be able to deal with my intended hp level of around 500.....or so.....plus, I had to sell a kidney to get those.....

240 heads and 470 cubic inch will get you near 600 HP by accident lol.

 

[MOPARMAGA]

I would not be afraid od the 1.120" conpression height piston. A 5.3 LS CH is typically around 1.115-1.35" and they go 200k miles. In addition, the 1.32" CH piston uses oil rail support rings.

LS engines run pretty tight piston to cylinder clearance with there hypereutectic pistons

 

[TT5.9mag]

Yah, I follow both JustMoparJoe and RustBucketRestos - love their stuff - next level in mho.... I picked up a Molnar 3.91 crank a 6.535 rods for a 470 build but I also have access to a 4.15 crank and was wondering about the possible combo's that are available. My main concern (from what I've read) is that the short skirt piston with the oil ring supports cause "piston slap" which does not seem desirable. I'm no engine builder so I'm trying to do the research before I go any farther. I picked up my TF 240 heads recently (Christmas present to myself) and Harland Sharp rockers so my 400 block will be headed to a machine shop soon - ish. I've been carrying that block around since 1996 and it's long past due for a build.....many roadblocks and detours along the way but LORD willing, this thing will live! Thanks for all the replies..... Not many (as in none) MOPAR friends so not much help or input - you guys and YouTube......

I built a twin turbo 489 BBC for my boat using a stoker kit with Mahle Motorsport pistons that had the oil rings down in the pin boss, which required oil support rails. I was concerned about longevity in the same way you are. I reached out to an engineer at Mahle and his response was “why don’t you let us worry about the strength of our pistons”. That was enough for me. I beat the crap out of that engine on the dyno and on the lake for a season now and it’s flawless. And it has .007 of skirt clearance. No audible slap at all. My point is, buy a good piston in the compression height you need and don’t worry about it. Put it together and beat on it like a red headed step child. I know I do.

 

[OLDSTYLE]

Check Ohio Crankshaft. I just ordered a 512ci rotating assm. for a B block from them. 4.25 stroke 4340 crank, 6.535 rods with 2000 bolts, Diamond dish pistons, and bearings & rings.

 

[TT5.9mag]

240 heads and 470 cubic inch should get you near 600 HP by accident lol.

I fixed it for you. Because some people can screw anything up.

 

[PRH]

Imo, the 4.25” stroke crank with the 2.200” crank pin is a “better” overall combo than the 4.15” stroke with the 2.375” crank pin(in both B and RB blocks).

 

[MOPARMAGA]

I built a twin turbo 489 BBC for my boat using a stoker kit with Mahle Motorsport pistons that had the oil rings down in the pin boss, which required oil support rails. I was concerned about longevity in the same way you are. I reached out to an engineer at Mahle and his response was “why don’t you let us worry about the strength of our pistons”. That was enough for me. I beat the crap out of that engine on the dyno and on the lake for a season now and it’s flawless. And it has .007 of skirt clearance. No audible slap at all. My point is, buy a good piston in the compression height you need and don’t worry about it. Put it together and beat on it like a red headed step child. I know I do.

Yes, oil support rings are not an issue. I have not seen an issue directly from them , and I am a redhead lol

 

[TT5.9mag]

Yes, oil support rings are not an issue. I have not seen an issue directly from them , and I am a redhead lol

I remember you saying you’re a redhead, and I thought of that when I typed it. No offense meant. I hope none taken.

 

[MOPARMAGA]

I remember you saying you’re a redhead, and I thought of that when I typed it. No offense meant. I hope none taken.

No offense at all lol. Good thing I never had step parents

 

[DGrace]

Yah, it would seem the 4.25 stroke crank would be a more viable option.....I was just trying to determine if getting the 4.15 stroke crank would be worth it. Like I mentioned, I have a Molnar 3.91 crank and 6.535 rods so I'll concentrate on that. What brand bearings are most guys going with these days? I have a set of Durabond PDP17 cam bearings (JustMoparJoe) for when I get the block work done - but what about main & rod bearings?? Thank you all.....

 

[TT5.9mag]

Yah, it would seem the 4.25 stroke crank would be a more viable option.....I was just trying to determine if getting the 4.15 stroke crank would be worth it. Like I mentioned, I have a Molnar 3.91 crank and 6.535 rods so I'll concentrate on that. What brand bearings are most guys going with these days? I have a set of Durabond PDP17 cam bearings (JustMoparJoe) for when I get the block work done - but what about main & rod bearings?? Thank you all.....

King or Clevite for the bearings.