What's wrong with running stock 400 sbc rods? - Chevelle Tech
Performance Our High Performance area

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
post #1 of 28 (permalink) Old Sep 23rd, 06, 2:49 AM Thread Starter
Senior Tech Team
Dave
 
Join Date: Mar 2004
Location: Goldsboro, NC
Posts: 5,977
What's wrong with running stock 400 sbc rods?

I have a 400 sbc sitting in my garage that I want to build. When I got it, it was a complete long block.

Everyone says the stock 5.650 rods are junk and to run 5.7 rods.

My question is what is wrong with the stock 400 rods? Are they weak? Are they not good for a high performance application?

If it helps any I was planning on making the engine into a nice street engine that can hold it's own. I was planning on running a nice roller cam but not build it radical. I just want something that would be close (if not more) to the power of an LS1 but not be tempermental and still have good street manners.

Also what about reusing the stock pistons? I don't plan to spray this engine. I will however ditch the 882's and run a set of Vortecs unless there's a better head to go with.

'71 Malibu 402 big block/TH350 trans - Sold 2 Jan '08
How to tell if your car is a true SS or not:http://www.chevelles.com/shop/ss_ident.html
Junkyard Dawg is offline  
Sponsored Links
Advertisement
 
post #2 of 28 (permalink) Old Sep 23rd, 06, 3:31 AM
Senior Tech Team
 
Join Date: Nov 2004
Location: Pittsburgh Pa
Posts: 2,111
Re: What's wrong with running stock 400 sbc rods?

Couple reasons really. Number one.....It dont matter how long the rod is.....most any small block chevy STOCK rod(5.7 inches, 24 inches.....9 feet....whatever) they aint all that great for performance apps. They arent the safest pieces you can use. You can work on em and get em prepped to take a bit of a beating, I wont doubt that. But for the money invested in refurbishing stockers to do a good job.....your most of the way to a descent forged(like a scat for example...good stuff at a good price)......so..........might as well step up since your almost there! Same with heads for example. Spend 600 bucks on doing the best you can with stock smoggers....or spend 200 more on the vortecs your looking at that will end up much better in the end.

Another thing....longer rods tend to reduce the load on the bores a hair. So the longer you go(rod lenght), the better chance you have on releiving stress and taking away load from the bores.

Also, longer rods are said to be LESS sensitive to detonation. Longer rods dwell longer at top dead center and less at bottom dead center. The longer dwell time at TDC is said to ease up on the pinging factor(good thing))....but some of these things are kinda hard to test. Im not building two identical motors with different rod lengths and running them just as hard and just as long just to see which one wears the bores less or pings less. Fortunately, the load thing can be graphed out, and although the difference is very minimal, there is a difference so you can see it. The pinging thing....you just have to try it, but its said to work by many and Im sure someone out there smarter with more time and cash than me has tested it in order for this theory to have developed.


Lastly....longer rods(especially aftermarket with better profiling) often allow for an easier(and cheaper) internal balance job. This is also proven in a lot of situations.

In the end.....buy GOOD rods. Thats the most important thing. You will hardly notice some of the other things I mentiond...but you will know right away if you break a rod.
greg_moreira is offline  
post #3 of 28 (permalink) Old Sep 23rd, 06, 5:56 AM
Lifetime Premium Member
Dan
 
Join Date: Jan 2006
Location: Somers,CT
Posts: 9,909
Re: What's wrong with running stock 400 sbc rods?

That is all good advise BUT. You can run the short rods in a 400 that will be kept under 6500. I ran my 400sb for 10 years in a 69 Nova bracket car that ran 11.50's @ 117,I shifted @ 5800 1 to 2 & 63 2 to 3. car had 4.56 gears in it.
After running it like that for 10 years (well over 500 1/4 passes & never blew up) I finally pulled it apart & put in the 5.7 eagles. Then I shifted @ 7200 & when 11.00 & 10.20 on a 150 N.OS. hit in 2 & 3. Don't be too afraid of the short rods but do put good bolts (arp) in them.

72 ss 454 "W" code,w/cowl induction (how many left?)
matching # LS5 454+.060" 9.2 :1, 2.19/1.88 valves,Comp HR cam 289/295 234/240 .613/.613 110* (dyno'd @ 557hp @ 5400 & 583tq @ 4100)
matching # M22 w/CF dual friction clutch.
Holley 750 HPs dp(82751) on Weiand Stealth & MSD Pro billet HEI
Hedman Elite headers/Flowmaster exh. (w/super 40s)
TC#3095
Garage find parked from 1978-2004

http://macswebs.com/ls5registry/bal/bal.htm
http://www.chevelles.com/showroom/sh...0&ppuser=25834
http://ssregistry.macswebs.com/1972/1d37w2b_reis.htm
http://www.youtube.com/watch?v=YqZkVw6xMkM
dreis454 is offline  
post #4 of 28 (permalink) Old Sep 23rd, 06, 7:08 AM
Senior Tech Team
 
Join Date: Dec 2005
Location: Lancaster, PA
Posts: 9,904
Re: What's wrong with running stock 400 sbc rods?

I believe that the 400 rod is 5.565 in length. So the difference in in length is greater.

Ray

http://s30.photobucket.com/albums/c3...t=DSC01615.jpg
Best pass so far 9.034 at 148.10, 1.242 60'
bracketchev1221 is offline  
post #5 of 28 (permalink) Old Sep 23rd, 06, 7:55 AM
Lifetime Premium Member
 
Join Date: Dec 2004
Location: woodbine, md
Posts: 6,779
Re: What's wrong with running stock 400 sbc rods?

usually you can go to a longer rod if your changing pistons, helps side loading, but the stock rods would be fine for what your doing

when your credit cards are maxed, have the limits raised
forcd ind is offline  
post #6 of 28 (permalink) Old Sep 23rd, 06, 8:46 AM
Tech Team
Roger
 
Join Date: Apr 2002
Location: Akron, OH, USA
Posts: 801
Re: What's wrong with running stock 400 sbc rods?

Quote:
Originally Posted by Junkyard Dawg View Post
...My question is what is wrong with the stock 400 rods? Are they weak? Are they not good for a high performance application?...
Also what about reusing the stock pistons? I don't plan to spray this engine. I will however ditch the 882's and run a set of Vortecs unless there's a better head to go with.
There is nothing wrong with the stock 400 (5.565") rods for a mild (say 400 hp) build, although they still need re-conditioned and good rod bolts. And, as Greg mentioned, at this point you're getting close to the price of aftermarket rods.

Likewise, for a mild build with no nitrous, there is nothing wrong with the stock pistons. Of course, if you go to a longer rod, you will have to change the pistons also and then it makes more sense to go with an aftermarket forged piston.

Roger Copeland
"Only a rich man can afford cheap parts, because he can afford to replace them."
R&R Racing
383Malibu is offline  
post #7 of 28 (permalink) Old Sep 23rd, 06, 9:06 AM
Tech Team
 
Join Date: Aug 2003
Location: Redding,CA
Posts: 978
Re: What's wrong with running stock 400 sbc rods?

The longer the rod...the lighter the piston
bigjimzlll is offline  
post #8 of 28 (permalink) Old Sep 23rd, 06, 11:33 AM
Senior Tech Team
Paul
 
Join Date: Jan 2001
Location: Columbia, MO, USA
Posts: 14,690
Smile Re: What's wrong with running stock 400 sbc rods?

My 406 has stock rods in it and has done fine shifting up around 6,000..

I didn't like to go much higher b/c the big motor just kinda felt/sounded like it was straining up there..

Not like the little bitty junk301 I've ran before that would go up until my points bounced fine and that was like 7,500 rpm or so back then.. The little sucker was made outta junk parts and was unbalanced to boot!!

pdq67

Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
pdq67 is offline  
post #9 of 28 (permalink) Old Sep 23rd, 06, 11:44 AM Thread Starter
Senior Tech Team
Dave
 
Join Date: Mar 2004
Location: Goldsboro, NC
Posts: 5,977
Re: What's wrong with running stock 400 sbc rods?

Thanx.....and yes my plans are to not spin this engine past 6000 rpm.

As mentioned I wanted to run a roller cam, probably a hydraulic unless it's better to run a mechanical.

Seems like most people build 400's to be tempermental 500 hp engines. My goal was to build mine with at the most a fairly lumpy idle....nothing radical...yet can give the LS1 boys a run for their money.

As mentioned I don't plan on spraying this engine. It may see some track time but it will spend 80% of it's life on the street.

Ditto on the ARP hardware. I guess for my application it's a hit or miss sort of deal.

Also I'm curious as to how much power I'd be making on what I'm wanting to do? You think 450 hp is out of reach? Or do I need to run some sort of wild cam/head combo for that?

'71 Malibu 402 big block/TH350 trans - Sold 2 Jan '08
How to tell if your car is a true SS or not:http://www.chevelles.com/shop/ss_ident.html
Junkyard Dawg is offline  
post #10 of 28 (permalink) Old Sep 23rd, 06, 11:53 AM
Lifetime Premium Member
Dan
 
Join Date: Jan 2006
Location: Somers,CT
Posts: 9,909
Re: What's wrong with running stock 400 sbc rods?

450hp is not out of reach but you are talking about a good size roller & decent set of heads. On mine I had a ft solid & dart sportsman 2's with 11 to 1 comp. The key for the cam is big duration in a 400sb. I was running 266 & 269 @ .050 on a 108 LC

72 ss 454 "W" code,w/cowl induction (how many left?)
matching # LS5 454+.060" 9.2 :1, 2.19/1.88 valves,Comp HR cam 289/295 234/240 .613/.613 110* (dyno'd @ 557hp @ 5400 & 583tq @ 4100)
matching # M22 w/CF dual friction clutch.
Holley 750 HPs dp(82751) on Weiand Stealth & MSD Pro billet HEI
Hedman Elite headers/Flowmaster exh. (w/super 40s)
TC#3095
Garage find parked from 1978-2004

http://macswebs.com/ls5registry/bal/bal.htm
http://www.chevelles.com/showroom/sh...0&ppuser=25834
http://ssregistry.macswebs.com/1972/1d37w2b_reis.htm
http://www.youtube.com/watch?v=YqZkVw6xMkM
dreis454 is offline  
post #11 of 28 (permalink) Old Sep 23rd, 06, 11:57 AM Thread Starter
Senior Tech Team
Dave
 
Join Date: Mar 2004
Location: Goldsboro, NC
Posts: 5,977
Re: What's wrong with running stock 400 sbc rods?

Would I need to run AFR's to achieve this goal? Or could I get away with Vortecs?

And would running the duration I need to get to make 450 hp cause the engine to be tempermental?

'71 Malibu 402 big block/TH350 trans - Sold 2 Jan '08
How to tell if your car is a true SS or not:http://www.chevelles.com/shop/ss_ident.html
Junkyard Dawg is offline  
post #12 of 28 (permalink) Old Sep 23rd, 06, 12:05 PM
Tech Team
 
Join Date: Sep 2001
Location: GADSDEN, ALABAMA
Posts: 760
Wink Re: What's wrong with running stock 400 sbc rods?

i have no problem with 400 rods at all with good bolts.i have run two engins identical in heads and cams and they both ran the same times the 400 rod motor did show a little bit better 60ft times but that has to do alot with track conditions.as mentioned i dont recomend turning them up over 6500 if you wont them to live.myself i would not spend the money on the roller for the street ,i think i would take that money and put in in a set of much better heads than the vortecs.you will be spending alot of money on those heads just to get them ready to run a roller cam.i also changed to a roller from a solid cam and did not pick up any better times at the track it did lighten my bill fold some though.for the street the vortecs and a good solid cam will be alot of fun to drive though.and remember its your money so spend it wisely

alan , gadsden ala. 66 chevelle bracket car best 6.95 in 1/8th big block now 67 nova bracket car best 6.739 in 1/8th 1.429 60ft at 100.45mph 400 sb
JUNK YARD DOG is offline  
post #13 of 28 (permalink) Old Sep 23rd, 06, 12:34 PM Thread Starter
Senior Tech Team
Dave
 
Join Date: Mar 2004
Location: Goldsboro, NC
Posts: 5,977
Re: What's wrong with running stock 400 sbc rods?

Quote:
Originally Posted by JUNK YARD DOG View Post
i think i would take that money and put in in a set of much better heads than the vortecs.you will be spending alot of money on those heads just to get them ready to run a roller cam.
What kinds of mods must be done to make a roller cam work with the heads?

Also did you mean to say you went from a solid hydraulic to a solid roller and dind't see any improvement?

So are you recommending a solid flat tappet for the street?

'71 Malibu 402 big block/TH350 trans - Sold 2 Jan '08
How to tell if your car is a true SS or not:http://www.chevelles.com/shop/ss_ident.html
Junkyard Dawg is offline  
post #14 of 28 (permalink) Old Sep 23rd, 06, 3:17 PM
Senior Tech Team
Paul
 
Join Date: Jan 2001
Location: Columbia, MO, USA
Posts: 14,690
Re: What's wrong with running stock 400 sbc rods?

Here you go from over at SGCOG!!

They have a big-time "sticky" on Vortec's!!

http://www.nastyz28.com/forum/showthread.php?t=56505

pdq67

Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
pdq67 is offline  
post #15 of 28 (permalink) Old Sep 23rd, 06, 4:11 PM
Senior Tech Team
 
Join Date: Feb 2005
Location: Michigan
Posts: 6,981
Re: What's wrong with running stock 400 sbc rods?

I'm running stock rods in my .030 over 400 SBC. Runs great and pulls awesome. This is by far the best engine I have ever owned as far as power. Nothing radical. Performer cam, Weiand stealth intake, 650 CFM Edelbrock carb, Headers, Performance HEI, Ect. I shift around 5,000 right now as it's still pretty fresh. I probabally will not spin it past 5,500 as it has everything stock on the bottom end as far as fasterners and such.
I have not experienced a 400 with the long rods so I can not attest to the difference. I'm sure they are better for the above mentioned reasons but I am very happy with mine. I built it 10 years ago and it sat on a engine stand till this spring. Not even sure the long rod was the "in" thing back in 96 or if it even existed.

LK
Alwhite00 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevelle Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address. Note, you will be sent a confirmation request to this address.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
SBC 400 Piston & Ring Selection Advice Needed. ~JM~ Engine 6 Jul 31st, 06 2:19 PM
Clearancing 400 block for 6" rods dirtrocker Performance 1 Nov 3rd, 05 1:38 PM
Chipped Lifter Bore - 400 SBC Bill's_72_SS Engine 4 Sep 6th, 05 4:02 PM
400 sbc at swap meet daaujla Engine 9 Jun 29th, 05 12:31 PM
vortec stock springs - anyone running them with a performance cam? Clyde_Maston Performance 14 Apr 25th, 04 7:21 AM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome