383vs400 crankshaft - Moparts Forums

Register Log In Moparts Forums Unlawfl's Race & Engine Tech 383vs400 crankshaft

Print Thread

Page 2 of 3

1

2

3

Re: 383vs400 crankshaft [Re: Performance Only] #1410723 03/31/13 08:36 PM 03/31/13 08:36 PM
Joined: May 2003 Posts: 6,561 Downtown Roebuck Ont Twostick Still wishing...
Twostick Still wishing... Joined: May 2003 Posts: 6,561 Downtown Roebuck Ont	Quote: Quote: Quote: John, 71 was the last year for the 383 and as you know, 72 was the first year for the 400. It stands to reason they wanted to deplete the old 383 cranks. I think we all know they'll physically interchange dimensionally. That does not mean that the component weights were the same. At the factory all they had to do was drill the counterweights differently. I understand that but the crankshaft was individually balanced to a set bobweight, if the 400 bobweight was that much different than the 383 they would have given the crank a different part number and a different balance but they didn't...so a parts room 2268114 crank would have been supplied as a direct replacement for either the 383 or the 400. Quote: The pistons are not close enough in weight to just swap cranks from a 383 to a 400 and not rebalance it. Again, depends on how much imbalance is considered "too much"....evidently the factory thought it wasn't enough to warrant a different part number. A crankshaft bought over the counter did not have balance holes drilled in it. Aside from that, how many forged crank 400's were ever built? I've never seen one. If you have ever seen a 400 that had a manual trans behind it, it had a forged crank in it. Lots of trucks for sure. Kevin

Re: 383vs400 crankshaft DELETED [Re: Pale_Roader] #1410724 03/31/13 09:13 PM 03/31/13 09:13 PM
Joined: Nov 2008 Posts: 1,565 tennessee P pushbutton pro stock
pushbutton pro stock P Joined: Nov 2008 Posts: 1,565 tennessee	Post deleted by pushbutton

Re: 383vs400 crankshaft [Re: pushbutton] #1410725 03/31/13 09:38 PM 03/31/13 09:38 PM
Joined: Nov 2003 Posts: 7,348 Mt.Vernon ,Ohio VernMotor master
VernMotor master Joined: Nov 2003 Posts: 7,348 Mt.Vernon ,Ohio	forged crank 400's were ever built? I have own 1 I think they are rare.. it was a cold weather block

Re: 383vs400 crankshaft [Re: pushbutton] #1410726 03/31/13 09:46 PM 03/31/13 09:46 PM
Joined: Jan 2003 Posts: 9,991 Frostbitefalls MN (Rocky&Bullw... gregsdart master
gregsdart master Joined: Jan 2003 Posts: 9,991 Frostbitefalls MN (Rocky&Bullw...	Quote: Can you bore a 400 block large enough to take a .030" over 440 piston? That would only be .008 overbore. A .060 440 piston would be .038 over bored 400. 400 bore, 4.342. 440 bore, 4.320 a Motor home or low compression passenger car piston might work. Even if you find the right piston in the bone pile, it may be way off on balance specs. According to the weights listed for replacement pistons, the stock 440 pistons are possibly 75 grams heavy. That equals a cut of about .110. Too much. Best bet is a stock weight replacement piston, or run what you have. Last edited by gregsdart; 03/31/13 10:20 PM. 8..603 156 mph best, 2905 lbs 549, indy 572-13, alky

Re: 383vs400 crankshaft [Re: Pale_Roader] #1410727 03/31/13 11:48 PM 03/31/13 11:48 PM
Joined: Jan 2003 Posts: 74,992 U.S.S.A. JohnRR I Win
JohnRR I Win Joined: Jan 2003 Posts: 74,992 U.S.S.A.	Quote: You could spend yourself poor at the machinist to reinvent the whole thing, or you could spend a few hundred on pistons. I've driven myself bats with the math on this puzzle... just buy the damn pistons! That said... i have a No-buck zero-deck 400 ready for the rebuild in my shop. Found a standard bore re-cond. 400 at the junkyard, free in trade. Had some .030" over 440 pistons (stock low comp, perfect comp ht. for lowdeck) kicking around. Enough rods to build a V700, and a couple steel 383 cranks. Bore the 400 to just 4.35", flycut the pistons, balance it all and pow! Zero-deck/steel crank/balanced 400 to go with some nice 516 heads and .040" quench. Total cost? $125 + machining/balancing. Kinda hokey... but i bet it screams. All that and not one use of your sillyass ov ... .. Did you add valve notches to those pistons? If you didn't don't get crazy with your cam choice.

Re: 383vs400 crankshaft [Re: Performance Only] #1410728 04/01/13 06:53 PM 04/01/13 06:53 PM
Joined: Jan 2003 Posts: 25,777 Rio Linda, CA John_Kunkel Too Many Posts
John_Kunkel Too Many Posts Joined: Jan 2003 Posts: 25,777 Rio Linda, CA	Quote: A crankshaft bought over the counter did not have balance holes drilled in it. I disagree. A parts room crank would have been exactly the same part that was supplied to the engine assembler at the Trenton engine plant.....spin balanced at another part of the plant using a specific bobweight. The INTERNET, the MISinformation superhighway

Re: 383vs400 crankshaft [Re: JohnRR] #1410729 04/02/13 07:30 AM 04/02/13 07:30 AM
Joined: Jan 2005 Posts: 4,862 the frozen wastes... Pale_Roader Swears too much
Pale_Roader Swears too much Joined: Jan 2005 Posts: 4,862 the frozen wastes...	Quote: Quote: You could spend yourself poor at the machinist to reinvent the whole thing, or you could spend a few hundred on pistons. I've driven myself bats with the math on this puzzle... just buy the damn pistons! That said... i have a No-buck zero-deck 400 ready for the rebuild in my shop. Found a standard bore re-cond. 400 at the junkyard, free in trade. Had some .030" over 440 pistons (stock low comp, perfect comp ht. for lowdeck) kicking around. Enough rods to build a V700, and a couple steel 383 cranks. Bore the 400 to just 4.35", flycut the pistons, balance it all and pow! Zero-deck/steel crank/balanced 400 to go with some nice 516 heads and .040" quench. Total cost? $125 + machining/balancing. Kinda hokey... but i bet it screams. All that and not one use of your sillyass ov ... .. Did you add valve notches to those pistons? If you didn't don't get crazy with your cam choice. DAMMIT!!!!! I'll try harder next time. I WILL, i promise! Flycut pistons (for valve clearance). Yes, part ov the budget (see?? see???). And that actually was the hangup that back-burnered the whole deal for now... flycutting the pistons. I'm too lazy to get that neat Isky tool and do it myself, and my machinist was too far away for the back and forth needed to get it going. No way i'd put together a neat combo like this and limit myself on cam size. I wish there was a standard template for flycutting a piston for valve notches. Something that didn't require giving him the entire pile or assembling it to figure it out. Or maybe i'm overthinking things? The whole point with this combo was NOT to succumb to the 'might-as-wells'...

Re: 383vs400 crankshaft [Re: Pale_Roader] #1410730 04/02/13 07:39 AM 04/02/13 07:39 AM
Joined: Jan 2005 Posts: 4,862 the frozen wastes... Pale_Roader Swears too much
Pale_Roader Swears too much Joined: Jan 2005 Posts: 4,862 the frozen wastes...	Okay... heres a hokey question... How much piston/bore clearance is just too much? Could you put a standard-bore 440 piston in a standard bore 400? (4.32" vs 4.3422") Assume compression height was viable (which it is, in fact). If so, what would make it last as long as possible? Only reason i'd even consider that was because this infamous old street racer (a Chevy guy but had done a lot ov time with nitroused junkyard 440's), said the craziest thing he'd done with a Dodge was running with .020" clearance in a 440 (.040" over pistons in a .060" over bore). Obviously done outta desperation, but he said it worked, and "probably didn't burn any more oil than a normal 440..." (bit ov a stab here). That was a pretty fast car apparently. His stuff always was.

Re: 383vs400 crankshaft [Re: Pale_Roader] #1410731 04/02/13 12:37 PM 04/02/13 12:37 PM
Joined: Jan 2003 Posts: 74,992 U.S.S.A. JohnRR I Win
JohnRR I Win Joined: Jan 2003 Posts: 74,992 U.S.S.A.	Quote: Quote: Quote: You could spend yourself poor at the machinist to reinvent the whole thing, or you could spend a few hundred on pistons. I've driven myself bats with the math on this puzzle... just buy the damn pistons! That said... i have a No-buck zero-deck 400 ready for the rebuild in my shop. Found a standard bore re-cond. 400 at the junkyard, free in trade. Had some .030" over 440 pistons (stock low comp, perfect comp ht. for lowdeck) kicking around. Enough rods to build a V700, and a couple steel 383 cranks. Bore the 400 to just 4.35", flycut the pistons, balance it all and pow! Zero-deck/steel crank/balanced 400 to go with some nice 516 heads and .040" quench. Total cost? $125 + machining/balancing. Kinda hokey... but i bet it screams. All that and not one use of your sillyass ov ... .. Did you add valve notches to those pistons? If you didn't don't get crazy with your cam choice. DAMMIT!!!!! I'll try harder next time. I WILL, i promise! Flycut pistons (for valve clearance). Yes, part ov the budget (see?? see???). And that actually was the hangup that back-burnered the whole deal for now... flycutting the pistons. I'm too lazy to get that neat Isky tool and do it myself, and my machinist was too far away for the back and forth needed to get it going. No way i'd put together a neat combo like this and limit myself on cam size. I wish there was a standard template for flycutting a piston for valve notches. Something that didn't require giving him the entire pile or assembling it to figure it out. Or maybe i'm overthinking things? The whole point with this combo was NOT to succumb to the 'might-as-wells'... ov When you said flycut I thought that was to trim the top of it to get it to zero , my bad. You could have bought some small carbides and soldered them to valves and cut them that way , keeping with your bucks down theme

Re: 383vs400 crankshaft [Re: John_Kunkel] #1410732 04/02/13 01:26 PM 04/02/13 01:26 PM
Joined: Jul 2010 Posts: 2,091 Delray beach, Florida P Performance Only top fuel
Performance Only top fuel P Joined: Jul 2010 Posts: 2,091 Delray beach, Florida	Quote: Quote: A crankshaft bought over the counter did not have balance holes drilled in it. I disagree. A parts room crank would have been exactly the same part that was supplied to the engine assembler at the Trenton engine plant.....spin balanced at another part of the plant using a specific bobweight. okay, if you say so it must be true. I've only bought a few cranks over the counter at a Plymouth dealership and none of them had balance holes in them. So in the end what your saying is that a forged internal 383 crank would have been balanced exactly the same as a cast crank external balance 400 crank and it's a true bolt in affair and will be within Chryslers balance limits? I respect your debate, but completely disagree based on my own experiences. machine shop owner and engine builder

Re: 383vs400 crankshaft [Re: Performance Only] #1410733 04/02/13 01:34 PM 04/02/13 01:34 PM
Joined: Jan 2003 Posts: 16,376 D dogdays I Live Here
dogdays I Live Here D Joined: Jan 2003 Posts: 16,376	Boy, I had promised myself I wouldn't jump into this thread, bt here goes... I don't think anyone is saying the crankshafts themselves are balanced the same. I was saying, and I think others were saying this too, that the bobweight to balance either crank would be the same, assuming the cast crank carried with it all its factory imbalance gear, such as flyweheel and harmonic damper. The rods are the same in all four cases and Chrysler was very good about keeping things weighing the same to reuse or keep using crankshafts. My best example is the extra heavy wristpins that they used in 273s in order to keep using the Poly 318 crankshaft and rods in the 273. The extra heavy wristpins made the 273 and 318 piston/pin weights equal. R.

Re: 383vs400 crankshaft [Re: Performance Only] #1410734 04/02/13 03:12 PM 04/02/13 03:12 PM
Joined: Jan 2003 Posts: 25,777 Rio Linda, CA John_Kunkel Too Many Posts
John_Kunkel Too Many Posts Joined: Jan 2003 Posts: 25,777 Rio Linda, CA	Quote: okay, if you say so it must be true. I've only bought a few cranks over the counter at a Plymouth dealership and none of them had balance holes in them. So I guess back in the day "Joe the dealer mechanic" at the small town dealership went to the parts room to get a replacement crank for 383 or 400 and the parts room guy would say "here's your crank, Joe, but you'll have to find somebody to balance it....nearest place is 100 miles away". Okay, I'm convinced...not. Quote: So in the end what your saying is that a forged internal 383 crank would have been balanced exactly the same as a cast crank external balance 400 crank Never said anything of the sort...what I said is that the FORGED crank for a 383 is the same as the FORGED crank for the 400 as evidenced by the same part number. If the bobweight that the crank was balanced to was significantly different for each they would be different cranks and would have gotten a different part number....they didn't. The INTERNET, the MISinformation superhighway

Re: 383vs400 crankshaft [Re: John_Kunkel] #1410735 04/02/13 05:47 PM 04/02/13 05:47 PM
Joined: Jul 2010 Posts: 2,091 Delray beach, Florida P Performance Only top fuel
Performance Only top fuel P Joined: Jul 2010 Posts: 2,091 Delray beach, Florida	Quote: Quote: okay, if you say so it must be true. I've only bought a few cranks over the counter at a Plymouth dealership and none of them had balance holes in them. So I guess back in the day "Joe the dealer mechanic" at the small town dealership went to the parts room to get a replacement crank for 383 or 400 and the parts room guy would say "here's your crank, Joe, but you'll have to find somebody to balance it....nearest place is 100 miles away". Okay, I'm convinced...not. Quote: So in the end what your saying is that a forged internal 383 crank would have been balanced exactly the same as a cast crank external balance 400 crank Never said anything of the sort...what I said is that the FORGED crank for a 383 is the same as the FORGED crank for the 400 as evidenced by the same part number. If the bobweight that the crank was balanced to was significantly different for each they would be different cranks and would have gotten a different part number....they didn't. I don't understand how both cranks can be the same part number since they both have a different stroke from the other. Can you post a copy of the parts information your talking about? A 383 is 3.375 stroke and a 400 is 3.380 stroke. Granted it's only .005" different but i don't believe they used the same part number crank for both engines. I will however believe it when you prove it to me. machine shop owner and engine builder

Re: 383vs400 crankshaft [Re: Performance Only] #1410736 04/02/13 06:34 PM 04/02/13 06:34 PM
Joined: Jul 2005 Posts: 727 Cleveland Ohio S sportfury70 super stock
sportfury70 super stock S Joined: Jul 2005 Posts: 727 Cleveland Ohio	http://www.moparts.org/Tech/Archive/motor/36.html

Re: 383vs400 crankshaft [Re: Performance Only] #1410737 04/02/13 06:52 PM 04/02/13 06:52 PM
Joined: Jul 2006 Posts: 4,319 Puyallup, WA S StealthWedge67 master
StealthWedge67 master S Joined: Jul 2006 Posts: 4,319 Puyallup, WA	"I don't understand how both cranks can be the same part number since they both have a different stroke from the other. Can you post a copy of the parts information your talking about? A 383 is 3.375 stroke and a 400 is 3.380 stroke. Granted it's only .005" different but i don't believe they used the same part number crank for both engines. I will however believe it when you prove it to me." I don't think you're correct about this. I have always understood that All B cranks share the same stroke and that this stroke is ACTUALLY 3.375, but many application data sheets round up to 3.38" Last edited by StealthWedge67; 04/02/13 06:55 PM. LemonWedge - Street heavy / Strip ready - 11.07 @ 120

Re: 383vs400 crankshaft [Re: StealthWedge67] #1410738 04/03/13 11:06 AM 04/03/13 11:06 AM
Joined: Jul 2010 Posts: 2,091 Delray beach, Florida P Performance Only top fuel
Performance Only top fuel P Joined: Jul 2010 Posts: 2,091 Delray beach, Florida	The factory service information lists the stroke i mentioned, as does Chiltons and motors manuals. Some people do round the numbers up but that doesn't make it accurate. 7652947-383400enginespecs.jpg (59 downloads) Last edited by Performance Only; 04/03/13 11:34 AM. machine shop owner and engine builder

Re: 383vs400 crankshaft [Re: Performance Only] #1410739 04/03/13 11:28 AM 04/03/13 11:28 AM
Joined: Jul 2010 Posts: 2,091 Delray beach, Florida P Performance Only top fuel
Performance Only top fuel P Joined: Jul 2010 Posts: 2,091 Delray beach, Florida	2nd page 7652973-383400enginespecs2.jpg (55 downloads) Last edited by Performance Only; 04/03/13 11:35 AM. machine shop owner and engine builder

Re: 383vs400 crankshaft [Re: Performance Only] #1410740 04/03/13 03:04 PM 04/03/13 03:04 PM
Joined: Jan 2003 Posts: 25,777 Rio Linda, CA John_Kunkel Too Many Posts
John_Kunkel Too Many Posts Joined: Jan 2003 Posts: 25,777 Rio Linda, CA	My Motor's Manual shows the 400 stroke as 3.375" Every FSM shows the 400 stroke as 3.375".....3.38" is just 3.375" rounded off to two digits. The 383 and the 400 have the same stroke and the forged cranks have the same part number easily verifiable in any factory parts book. The INTERNET, the MISinformation superhighway

Re: 383vs400 crankshaft [Re: John_Kunkel] #1410741 04/03/13 04:22 PM 04/03/13 04:22 PM
Joined: Jul 2010 Posts: 2,091 Delray beach, Florida P Performance Only top fuel
Performance Only top fuel P Joined: Jul 2010 Posts: 2,091 Delray beach, Florida	My 1970 FSM shows the 383 as 3.375 In the end it doesn't really matter. One would be foolish to replace one crank with the other and not balance it. The factory balance was not that close to begin with and the 383 and 400 DO have a different bobweight, believe it or not. machine shop owner and engine builder

Re: 383vs400 crankshaft [Re: Performance Only] #1410742 04/03/13 06:09 PM 04/03/13 06:09 PM
Joined: Jan 2003 Posts: 25,777 Rio Linda, CA John_Kunkel Too Many Posts
John_Kunkel Too Many Posts Joined: Jan 2003 Posts: 25,777 Rio Linda, CA	Quote: My 1970 FSM shows the 383 as 3.375 So does mine, and my later FSM's show the 400 at 3.375" also. Quote: In the end it doesn't really matter. One would be foolish to replace one crank with the other and not balance it. The factory balance was not that close to begin with So anybody that assembles a motor with a stock replacement crank is "foolish"? Okay. Quote: and the 383 and 400 DO have a different bobweight, believe it or not. Once again, actual numbers would make your argument more creditable.....should be no sweat for an experienced shop owner and builder. The INTERNET, the MISinformation superhighway

Page 2 of 3

1

2

3

Moderated by Al_Alguire, Hotwheelsjr, moparts, not_a_charger, RangerDan440, tboomer

Hop To

Powered by UBB.threads™ PHP Forum Software 7.7.1