B engine rods

[Paul Secoy]

Hello all, I am building a stock stroke 400 B engine, and am having difficulty in locating an aftermarket rod that is stock length, but uses the now common .990" piston pin. It seems all I find either use the older, bigger Mopar pin, which limits piston selection, or they are an odd length intended for a stroker combination. I would like to find a rod set in the $500 range, which is easy to do it would seem except in my case. I've spent 2 days looking, and would really appreciate any help you can provide. Thanks, Paul.

 

[440Coronet500]

Take a look at SCAT, they might make them. 440'

 

[Dipstick]

Any rod that uses the 1.094" pin should be able to be bored and bushed to take the .990" pin.

 

[Lefty71]

https://www.manciniracing.com/eagchysb36hb.html

I see what you mean...still do-able tho with the bushed pins. Or you could make a nice filleted crank and use these; https://www.cnc-motorsports.com/eag...le-h-beam-connecting-rods-chrysler-b-400.html

You don't have to make a stroker, but if you are gonna pay $600 more for pistons, i would cetainly think about it.

 

[Paul Secoy]

https://www.manciniracing.com/eagchysb36hb.html

I see what you mean...still do-able tho with the bushed pins. Or you could make a nice filleted crank and use these; https://www.cnc-motorsports.com/eag...le-h-beam-connecting-rods-chrysler-b-400.html

You don't have to make a stroker, but if you are gonna pay $600 more for pistons, i would cetainly think about it.

Thanks for the replies and links. I hadn't considered re bushing. Also note that a lot of these rods are listed at a different length than stock, by a few hundreths of an inch. I really won't need the extra cubes of a stroker motor with my combo, but I will need some decent rods. Please keep the suggestions coming, Id like to keep the ball rolling on this one.

 

[Paul Secoy]

Rods are listed at 6.358" (stock) others at 6.385", (not so stock) but easily confused. I ordered a stud girdle instead this week until I figure this rod mess out.

 

[Paul Secoy]

Take a look at SCAT, they might make them. 440'

Looks like SB and RB only from SCAT. I did figure out where the odd 6.385" rods marketed for Mopars come from, it seems to be a stock length for Chevies, not surprising. Nothing I can use though.

 

[33 IMP]

Most, if not all, .990 pin rods are big block Chevy derivatives, the 6.385s are .250 longer than stock. (6.135)
They also are big block Chevy journal size and width, 2.200 journal. The stroker cranks are made for b or rb main size, but the rods are sized for Chevy big end.
Big Chevy rods won't like your stock b block crank at all, without extensive rework.
I would look for I beams for a 383, and plan on getting them bushed. That way you get the lighter pin, and keep your mopar big end. (Maybe 440 source?)
Next challenge will be pistons. Probably ten times more pistons available for strokers than stock cranks.

 

[33 IMP]

Imho, unless I had some pistons that were exactly what i wanted for my build, i wouldn't even begin trying to put together a stock stroke performance 400.
The strokers have 4340 cranks, longer,stronger,better rods, MUCH lighter pistons, newer style rings, lighter pins.
If you have to buy custom pistons for your 400 build, buy rods and then rework them, grind,polish and balance your crank (it is steel right?), you are three quarters the way to a stroker.
Nothing says you have to go all out, for a 512, there are 451 and 470 variants. with no durability problems
Sometimes it's better to do things the easy way.

 

[Paul Secoy]

Most, if not all, .990 pin rods are big block Chevy derivatives, the 6.385s are .250 longer than stock. (6.135)
They also are big block Chevy journal size and width, 2.200 journal. The stroker cranks are made for b or rb main size, but the rods are sized for Chevy big end.
Big Chevy rods won't like your stock b block crank at all, without extensive rework.
I would look for I beams for a 383, and plan on getting them bushed. That way you get the lighter pin, and keep your mopar big end. (Maybe 440 source?)
Next challenge will be pistons. Probably ten times more pistons available for strokers than stock cranks.

Yeah, I never thought stock would be so exotic.. I'm still coming up empty, 440 Source was a no go. I may have to stroke this to 451 just to get a decent rod and piston, not at all what I wanted, but may be my only choice.

 

[BSB67]

Could use the factory rod. Almost impossible to hurt a factory rod with good bolts in a 3.38 stroke motor. Add lighter piston and pin at its a 7000 +rpm deal.

 

[Curiousyellow71]

What pistons are you trying to use with a .990 pin?

 

[Paul Secoy]

What pistons are you trying to use with a .990 pin?

It looks like any decent forged has gone to that pin size. It seems only cast, Hypereutectic and Speed Pro old school forged are retaining the larger pin size.

 

[Paul Secoy]

Could us the factory rod. Almost impossible to hurt a factory rod with good bolts in a 3.38 stroke motor. Add lighter piston and pin at its a 7000 +rpm deal.

Its going to get a few Psi worth of help, enough to really worry me without some decent parts in the bottom end.

 

[Curiousyellow71]

My guess the pistons you are trying to make work on your 400 are for a 500 ci in stroker 440. The only way to use those is going to be bushing the stock length rods and run a free floating pin. Bushing rods is common but its towards an extra $200 you will have to invest. What BSB67 is suggesting would be a better direction. Use the longer 440 rod, arp bolts and run a piston that weighs 200+ grams less then a oem piston. A stock compression height 400 piston is massive. The short piston will get rid of reciprocating mass and let in wind up better and live. If you go to a 440 6.76 rod you can get them for the .990 pin in aftermarket or ...bush a stock rod with arp bolts. That direction would be less expensive then bushing any 400 stock length rods and superior...Imo
But...I think your going to be looking at decking the block to get the right deck height with any 400 stock stroke "pistons off the shelf" combo. That or a set of custom pistons..like racetech. A 451 is not going to cost much more. The only reason I'd do a aftermarket rod 400 is if I was turbocharging or running a class with limited displacement.

 

[andyf]

Hello all, I am building a stock stroke 400 B engine, and am having difficulty in locating an aftermarket rod that is stock length, but uses the now common .990" piston pin. It seems all I find either use the older, bigger Mopar pin, which limits piston selection, or they are an odd length intended for a stroker combination. I would like to find a rod set in the $500 range, which is easy to do it would seem except in my case. I've spent 2 days looking, and would really appreciate any help you can provide. Thanks, Paul.

Do you already have a set of pistons that you are trying to use? If not then stop worrying about finding B rods and use RB rods and find a piston that works with them. I'd be surprised if you could even find a good piston for a stock stroke 400 anymore but maybe someone is making one. The other option is to just use stock replacement parts if this isn't going to be a high performance build. The stock B rods will last forever in a mild build. They are heavy with a heavy pin and a heavy piston but if it is a mild build none of that really matters.

 

[Paul Secoy]

Do you already have a set of pistons that you are trying to use? If not then stop worrying about finding B rods and use RB rods and find a piston that works with them. I'd be surprised if you could even find a good piston for a stock stroke 400 anymore but maybe someone is making one. The other option is to just use stock replacement parts if this isn't going to be a high performance build. The stock B rods will last forever in a mild build. They are heavy with a heavy pin and a heavy piston but if it is a mild build none of that really matters.

I guess I should have been more clear about this build, I'm sorry. It will be a turbo build, and I already have the turbo. I will be using a steel 383 crank which I have in abundance. I think the shorter stroke would be a little easier on the bottom end, and with the turbo, I don't think I really need any more cubes. I can find Eagle rods rated for enough HP, but they for some reason come with the larger pin. Plenty of pistons exist that put me in my target range of 9.0 to 9.5 compression, but almost all now use the .990' pin. If I trusted a KB Hypereutectic, they make several pistons with the bigger pin diameter, I just would prefer a forged. I'm not trying to cut any corners where it will bite me, but there is certainly a budget.

 

[andyf]

Well in that case it is an easy problem to solve. Use a high quality 440 rod with a 0.990 pin and a semi-custom piston to get you the correct pin height. You just order a shelf piston with a different compression height.

 

[Curiousyellow71]

No cast or hypereutectics for boost especially with that big of bore unless only running a couple lbs. For turbo pistons forged 2000 series alloy is best.
Another possible option for you...
icon Ic829 piston and a molnar 6.86 hemi length rod w .990 pin.

 

[Paul Secoy]

Thank you very much for the suggestions, I've never run anything other than the factory length rods in the few builds I've done. I have been running different combinations around with no joy thus far, although some are close. The ICON 829 with the Hemi rod comes in about .17" higher in the bore than a similar 9.3/1 flat top, and my best 6.760" rod combo is about that much less. I'll keep looking.