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Re: 400 BB Mopar budget dyno test
[Re: Crazy68Dart]
#1190594
03/04/12 06:35 PM
03/04/12 06:35 PM
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Joined: Jan 2003
Posts: 27,421
Balt. Md
383man
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,421
Balt. Md
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Thanks for the comments about my boys Dart. We are happy with it for a 400 pump gas driver at 3550 and 3.91's. I keep telling him I will help him step it up some but he has his mind set on turbo charging it down the road !  Well who knows ?  I remember one of the Mopar mags did a 400 build and dynoed it about 10 years or so back and I know I have the mag in my pile of a mllion or so mags. I cant remember what it made but I remember it was a budget build. Ron
Last edited by 383man; 03/04/12 06:36 PM.
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Re: 400 BB Mopar budget dyno test
[Re: Chris2581]
#1190596
03/04/12 08:36 PM
03/04/12 08:36 PM
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Joined: Jan 2003
Posts: 5,484
SoCal
Brian Hafliger
OP
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OP
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Posts: 5,484
SoCal
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We didn't fill the water jackets...sorry if that was misleading.
I meant we just used a stock block with stock parts and KB pistons.
Everytime I use the Thumpr cams they make good power with a very wide powerband. We probably could have made more power with the 275HL cam but I like that the thumpr is on a 107lca and with low compression it helps kick up the low end power.
Plus with stock rockers, too much lift is a bad thing.
The heads flowed 243cfm at .550 lift and 241 at .500 I think.
From the crack of the intake valve it really flowed well up to .500 lift.
I believe there was about .045 left of the open chamber, so with a .045 gasket it was about .090 which can be bad if you don't plan it right. We installed the cam straight up instead of advanced like Comp recommends to keep from having too much cranking psi and to give some top end power to a stock headed/rocker arm'd build.
I'm sorry I forgot to take pics of the dyno sheet, I know that will answer alot of questions but I can tell you I wouldn't hesitate building this exact combo for a customer...except I would recommend a 1.6 aftermarket rocker assembly for power and durability reasons. I don't know just how long the stock rockers will hold up to 6000rpm and 280lbs. of spring pressure.
Brian Hafliger
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Re: 400 BB Mopar budget dyno test
[Re: WO23Coronet]
#1190597
03/04/12 08:44 PM
03/04/12 08:44 PM
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Joined: Jan 2003
Posts: 5,484
SoCal
Brian Hafliger
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SoCal
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Quote:
Quote:
Just finished doing a 2 part build using a 400BB Mopar.
We took a steel 383 crank, stock rods, KB flat top pistons and filled the stock 400 block. First test was with 906 heads, milled .050 for 79cc and compression was 9.8:1 and zero decked.
We chose a thumpr hyd. cam, stock rockers, bowl cleanup in the ports, stock valve sizes (manley valves)and comp single springs.
Topped with an rpm intake, 1" open spacer and a box stock 750holley it made 427HP @ 5700rpm and 443Tq @ 4200rpm using TTI 1 7/8 headers. Here's a pic....
What are the specs on the Thumpr cam and is it a tall fill or short fill? What kind of water and oil temps were you seeing with the fill? Also, how much of a recess is left in the chambers in the quench area after milling the heads .050? Where you able to get any kind of half decent quench clearences? Or will I have to wait for the magazine article to find out?  
The thumpr is 227-241@ .050 and 480's-.490's lift. But with stock rockers lift is more like .450's and .460's.
LCA is 107
Brian Hafliger
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Re: 400 BB Mopar budget dyno test
[Re: Brian Hafliger]
#1190600
03/05/12 08:29 PM
03/05/12 08:29 PM
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Joined: Feb 2010
Posts: 155
Tulsa oklahoma USA
2734bbl
member
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member
Joined: Feb 2010
Posts: 155
Tulsa oklahoma USA
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Quote:
Quote:
At those specs what octane gas are you using? Waht would you gues the power out put to be for a 440 vs 400?
We used AM/PM 91 octane from a pump.
440 should make a few more HP, and around 30-40 more TQ.
(quote)I believe there was about .045 left of the open chamber, so with a .045 gasket it was about .090 which can be bad if you don't plan it right. We installed the cam straight up instead of advanced like Comp recommends to keep from having too much cranking psi and to give some top end power to a stock headed/rocker arm'd build(quote)
I assume this means this engine was built in mind to not be detonation prone with 91 octane in a street car?
The reason I ask is I have a 440 (with KBs) at zero deck with(same gasket) 452s and a smaller Powerizer cam (467/262 232@.50 IIRC) and I had detonation problem when it got to be summer time. The engine stayed about 190-200 or so when it was 95* outside. I started to lose a lobe so know I have to replace the camshaft.
I plan to mirror your recipe so I know what to expect.
Thank you 
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Re: 400 BB Mopar budget dyno test
[Re: 2734bbl]
#1190601
03/05/12 08:59 PM
03/05/12 08:59 PM
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Joined: Jan 2003
Posts: 5,484
SoCal
Brian Hafliger
OP
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OP
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SoCal
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In order to curb detonation, you need to keep temps as controlled as possible.
Actually, this engine was zero decked for the 2nd part build which used closed chamber heads. And at .090 between the head and piston...you could have detonation during the hotter months.
I suggest milling the heads a bit less, and removing anything in the chamber that might be sharp.
I would also run a step colder plug than stock. And total timing should be kept to 35 max. This is if you live in hotter climates and closer to sea level. The higher up you go, the less it trouble it will be.
I also did not advance the cam...even at 9.8:1 so you have to be carefull what you do!!
Brian
Brian Hafliger
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Re: 400 BB Mopar budget dyno test
[Re: Brian Hafliger]
#1190602
03/05/12 09:17 PM
03/05/12 09:17 PM
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Joined: Feb 2010
Posts: 155
Tulsa oklahoma USA
2734bbl
member
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Joined: Feb 2010
Posts: 155
Tulsa oklahoma USA
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Interesting you post this because I was trying to decide if I should mill the 452s as you did here or go 915s. I could go either way right now as I have both available.
The engine ran plenty good I just had to start pulling out timing as the summer temps got up there.In the end I had 10* out of it but it was 100* plus outside !
Last edited by 2734bbl; 03/05/12 09:21 PM.
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Re: 400 BB Mopar budget dyno test
[Re: Brian Hafliger]
#1190605
03/05/12 11:26 PM
03/05/12 11:26 PM
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Joined: Jan 2012
Posts: 75
North Carolina
Mopar dragster
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Joined: Jan 2012
Posts: 75
North Carolina
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I just sold a set of 915's on here two weeks ago ready to go with new stainless valves, hardened seats, the whole shebang. Quote:
Quote:
Interesting you post this because I was trying to decide if I should mill the 452s as you did here or go 915s. I could go either way right now as I have both available.
The engine ran plenty good I just had to start pulling out timing as the summer temps got up there.In the end I had 10* out of it but it was 100* plus outside !
I tried like you can't believe to find a set of 915's so I could take advantage of the zero decking but I had no luck.
These 906's were virgin, so I did get lucky there. I would use the 915's and set the chambers at 79cc.
You will have to chamber cut them and work them a little but it's worth it.
Please see my brother Darrell Kiger at Wyo Racing and Rods for all of your drag car fabrication and restoration needs. From Pro Mod to concours restorations, he is the man. (336)463-4309.
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