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Carb? 408 to 434 #1999996 01/27/16 08:52 PM 01/27/16 08:52 PM
Joined: Oct 2003 Posts: 11,684 W. Kentucky justinp61 OP I Live Here
justinp61 OP I Live Here Joined: Oct 2003 Posts: 11,684 W. Kentucky	Since my 434 is almost done I'm trying to work off the short list to get it ready for the dyno. I have a Bigs 950HP that was tuned for the 408. It's been sitting for almost a year so I'm taking it apart giving a good cleaning and installing new gaskets. How much should I jet it up for the initial pull? Thanks

Re: Carb? 408 to 434 [Re: justinp61] #2000003 01/27/16 09:02 PM 01/27/16 09:02 PM
Joined: Jan 2007 Posts: 8,042 Mt Morris Michigan mopar dave master
mopar dave master Joined: Jan 2007 Posts: 8,042 Mt Morris Michigan	It probably has something like 74/83 in it. I would either leave it alone or maybe just put 2 more in it front rear. Dyno operator will know right off if its lean. http://www.youtube.com/watch?v=aIxaesJ190U http://youtu.be/lCZAaN7fFLg

Re: Carb? 408 to 434 [Re: justinp61] #2000010 01/27/16 09:06 PM 01/27/16 09:06 PM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Its gonna depend on the rpm on the peak HP.. for the time jet up a couple then check the A/F ratio on the dyno

Re: Carb? 408 to 434 [Re: justinp61] #2000079 01/27/16 10:41 PM 01/27/16 10:41 PM
Joined: Jan 2003 Posts: 31,049 Oregon A AndyF I Win
AndyF I Win A Joined: Jan 2003 Posts: 31,049 Oregon	You don't need to change the jets just because it is going on a bigger engine. The carb self adjusts. More airflow pulls harder on the jet and pulls in more fuel. You only need to change the jets if the weather changes or the altitude. You can jet up to be safe but if the carb was correctly calibrated before then it should be fine now.

Re: Carb? 408 to 434 [Re: AndyF] #2000085 01/27/16 10:47 PM 01/27/16 10:47 PM
Joined: Jul 2006 Posts: 4,319 Puyallup, WA S StealthWedge67 master
StealthWedge67 master S Joined: Jul 2006 Posts: 4,319 Puyallup, WA	Originally Posted By AndyF You don't need to change the jets just because it is going on a bigger engine. The carb self adjusts. More airflow pulls harder on the jet and pulls in more fuel. You only need to change the jets if the weather changes or the altitude. You can jet up to be safe but if the carb was correctly calibrated before then it should be fine now. ^^^This!^^^ LemonWedge - Street heavy / Strip ready - 11.07 @ 120

Re: Carb? 408 to 434 [Re: justinp61] #2000153 01/28/16 12:04 AM 01/28/16 12:04 AM
Joined: Jul 2004 Posts: 19,318 State of confusion T Thumperdart I Live Here
Thumperdart I Live Here T Joined: Jul 2004 Posts: 19,318 State of confusion	If it was good on the other motor I`d run it and watch the afr`s, read the plugs and go from there....... 72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....

Re: Carb? 408 to 434 [Re: justinp61] #2000718 01/28/16 09:41 PM 01/28/16 09:41 PM
Joined: Oct 2003 Posts: 11,684 W. Kentucky justinp61 OP I Live Here
justinp61 OP I Live Here Joined: Oct 2003 Posts: 11,684 W. Kentucky	Thanks guys, I'll jet up two on both ends for just good measure.

Re: Carb? 408 to 434 [Re: justinp61] #2000758 01/28/16 10:47 PM 01/28/16 10:47 PM
Joined: Dec 2014 Posts: 304 Florida M Mark Whitener enthusiast
Mark Whitener enthusiast M Joined: Dec 2014 Posts: 304 Florida	I wouldn't go up at all. 2 jet sizes is a bunch. Jet up one at a time art the track to see if it improves, down if the first hurts it. Last edited by Mark Whitener; 01/28/16 10:48 PM. Mark Whitener [url=www.racingfuelsystems.com[/url]

Re: Carb? 408 to 434 [Re: justinp61] #2000837 01/29/16 12:35 AM 01/29/16 12:35 AM
Joined: Oct 2003 Posts: 11,684 W. Kentucky justinp61 OP I Live Here
justinp61 OP I Live Here Joined: Oct 2003 Posts: 11,684 W. Kentucky	Thanks, I'll start with the current set up and see how it looks.

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