Disappointing first time out
#1016993
06/20/11 03:47 PM
06/20/11 03:47 PM
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Joined: Oct 2003
Posts: 4,013 South Park, Pa.
68LAR
OP
master
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OP
master
Joined: Oct 2003
Posts: 4,013
South Park, Pa.
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We had just finished installing a 440 in my friends' '65 Coronet. We pulled his 383 that ran a best of 12.5 something. Using the same cam, heads, carb, headers and drivetrain, we were looking for at least a .5 decrease in ET. The car ran the same as with the 383. We picked up .3 only when we dropped the exhaust at the collectors. It has a 3500 stall converter, 4.30 gears and 28" tall slick. The car launches a lot better, but seems to slow down from around half track on. I'm thinking this thing should be 60'ing in the low 1.6 range instead of 1.7-1.8 and running at least low 12's to high 11's. Any suggestions?
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
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Re: Disappointing first time out
[Re: 68LAR]
#1016995
06/20/11 04:12 PM
06/20/11 04:12 PM
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Joined: Nov 2004
Posts: 2,825 Sk. Canada
RemCharger
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master
Joined: Nov 2004
Posts: 2,825
Sk. Canada
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440s have a lot extra weight flapping around in there. Not really surprised they run the same. j/k I would look at compression differences and maybe cam timing?
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Re: Disappointing first time out
[Re: maxi426]
#1016996
06/20/11 04:15 PM
06/20/11 04:15 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
Check fuel pressure? Motor might be making a little steam, and now has a fuel supply issue?
I would look at the fuel supply
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Re: Disappointing first time out
[Re: 68LAR]
#1016997
06/20/11 04:23 PM
06/20/11 04:23 PM
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Joined: Nov 2009
Posts: 2,177 ill
dennismopar73
top fuel
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top fuel
Joined: Nov 2009
Posts: 2,177
ill
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not a big enough change 383-440 , 12.50 and you only did the swap to the 440, 12.teens 12.20s good air 12.0s you could actualy have a fuel issue, which could have held the 383 back??
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Re: Disappointing first time out
[Re: 68LAR]
#1016999
06/20/11 04:58 PM
06/20/11 04:58 PM
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Joined: Aug 2003
Posts: 43,228 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,228
Bend,OR USA
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Quote:
We had just finished installing a 440 in my friends' '65 Coronet. We pulled his 383 that ran a best of 12.5 something. Using the same cam, heads, carb, headers and drivetrain, we were looking for at least a .5 decrease in ET. The car ran the same as with the 383. We picked up .3 only when we dropped the exhaust at the collectors. It has a 3500 stall converter, 4.30 gears and 28" tall slick. The car launches a lot better, but seems to slow down from around half track on. I'm thinking this thing should be 60'ing in the low 1.6 range instead of 1.7-1.8 and running at least low 12's to high 11's. Any suggestions?
Several thnings, on the cam did you install it at the same lobe centers on the 440 Or did you advance, retard or just stick it in on the dots If you guys just stuck it in you need to degree it or at least check and set the intake lobe centers Second thing ,what do the spark plugs look like now from the 440, if you put new ones in Lots of ways to slow cars down, even when your not trying to do that Let us know what you find and do to correct it
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Disappointing first time out
[Re: Cab_Burge]
#1017000
06/20/11 06:20 PM
06/20/11 06:20 PM
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Joined: Oct 2003
Posts: 4,013 South Park, Pa.
68LAR
OP
master
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OP
master
Joined: Oct 2003
Posts: 4,013
South Park, Pa.
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Cam was degreed to a 105* on a 106* recommended. My first thought was fuel pressure, but he doesn't have a guage visable from the cab, so it could be monitored. He runs a blue pump with 3/8" line. If it would go low 12's we both would be happy. This is, as I stated, where we were hoping to be on the first outting. Trap RPM is 6000, but it takes a seemingly long time to gain rpm between shifts. Plugs looked good, no fouling or over rich indications.
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
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Re: Disappointing first time out
[Re: 68LAR]
#1017003
06/20/11 07:36 PM
06/20/11 07:36 PM
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Joined: Nov 2007
Posts: 778 Sherwood park, Alberta.
go green
super stock
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super stock
Joined: Nov 2007
Posts: 778
Sherwood park, Alberta.
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Quote:
The car launches a lot better, but seems to slow down from around half track on.
Your heads will only support so much power , by raising your cubic inches you are making it sign off earlier.
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Re: Disappointing first time out
[Re: 68LAR]
#1017006
06/21/11 12:06 AM
06/21/11 12:06 AM
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Joined: Jan 2003
Posts: 6,591 Canton, Ohio
Sport440
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master
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Posts: 6,591
Canton, Ohio
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You left out the head info And the MPH change between the 1/8 and 1/4.
Last edited by Sport440; 06/21/11 01:03 AM.
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Re: Disappointing first time out
[Re: Thumperdart]
#1017008
06/21/11 12:21 AM
06/21/11 12:21 AM
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Joined: Oct 2007
Posts: 3,978 Hilltown Pa
1967dartgt
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master
Joined: Oct 2007
Posts: 3,978
Hilltown Pa
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Did you change the carb at all when switching from one motor to the next?
Brett Miller W9 cnc'd heads STR Chassis fabraction
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Re: Disappointing first time out
[Re: 68LAR]
#1017009
06/21/11 02:17 AM
06/21/11 02:17 AM
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Joined: Nov 2009
Posts: 2,177 ill
dennismopar73
top fuel
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top fuel
Joined: Nov 2009
Posts: 2,177
ill
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Re: Disappointing first time out
[Re: 68LAR]
#1017011
06/21/11 09:37 AM
06/21/11 09:37 AM
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Joined: Nov 2009
Posts: 2,177 ill
dennismopar73
top fuel
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top fuel
Joined: Nov 2009
Posts: 2,177
ill
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75-?100 lbs down on comp, the 50 plus cubes off set the weight & compression diff something tells me the 383 wasnt running correct either, something was amissed there? may be the same reason the 440 doesnt run alittle better, timming /shift point fuel delievery,convert/ trans issue? the 440 does have a little more torq # yes, if everything the same, the 440 would run slightly better, not no half sec, jmo hard to say what yo have going on over a keyboard , could be several issues??
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