Previous Thread
Next Thread
Print Thread
What carburetor jetting as a starting point? #1238650
05/24/12 12:15 AM
05/24/12 12:15 AM
Joined: Apr 2009
Posts: 3,415
Toronto
M
mshred Offline OP
master
mshred  Offline OP
master
M

Joined: Apr 2009
Posts: 3,415
Toronto
Hey guys, looking for a jetting recommendation as a starting point for the following combo (sorry if its a little long, copied it from another post)

360 LA roller block bored .030" over
3.58 stock stroke, Scat I beams, SRP flatops
10.25:1 compression
RHS heads ported by Brian at IMM (291 cfm at .600 lift on the intake, 212cfm at .600 lift on the exhaust)
Custom Comp Hydraulic roller cam spec'd by Brian at IMM- 108 lsa installed straight up, 240/248 duration at .050", 630/580 lift split
Eddy RPM air gap intake, 750HP holley
1-5/8 headers, 3" exhaust dumped
4.10 gear dana 60, 28"x 12.5 ET streets, 4 speed

I'll probably be shifted between 6600-6800rpms, not sure on leave rpm yet (two step)

Carb is currently 74 primary jet, 80 secondary jet, with 35 squirters front and back- I think the car wanted more jet last year with the old combo, but I never got around to it....so what would you guys recommend as a starting point?

Thanks!

Re: What carburetor jetting as a starting point? [Re: mshred] #1238651
05/24/12 01:01 AM
05/24/12 01:01 AM
Joined: Aug 2003
Posts: 43,223
Bend,OR USA
C
Cab_Burge Online work
I Win
Cab_Burge  Online Work
I Win
C

Joined: Aug 2003
Posts: 43,223
Bend,OR USA
Start with what you got, drive it at part throttle and check the plugs, adjust accordling Once you got it like you want that part then try WOT, look at the plugs and go from there BTW, is the Holley stock with all parts or modified some? If stock what list number including the dash # is it? I can look it up and post the stock jetting for you If stock I like to start with the stock jetting, put the power valve in it that it needs to idle in gear and go from there, adjust as needed


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: What carburetor jetting as a starting point? [Re: Cab_Burge] #1238652
05/24/12 02:17 AM
05/24/12 02:17 AM
Joined: Jan 2003
Posts: 27,421
Balt. Md
3
383man Offline
Too Many Posts
383man  Offline
Too Many Posts
3

Joined: Jan 2003
Posts: 27,421
Balt. Md
I agree that I would start at what you have in it now as that may not be to far off for your combo. Then as Cab stated you can work from there if needed. I take it this is in that very fine super clean Scamp you have ? I really like your Scamp as it is one fine looking car. Good luck and keep us posted on the progress. Ron

Re: What carburetor jetting as a starting point? [Re: mshred] #1238653
05/24/12 08:18 AM
05/24/12 08:18 AM
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY Offline
Master
MR_P_BODY  Offline
Master

Joined: Jun 2003
Posts: 52,972
Romeo MI
Go to the Holley web site and see what the stock settings
are and start there or 2 jet sizes up on all 4

Re: What carburetor jetting as a starting point? [Re: MR_P_BODY] #1238654
05/24/12 08:22 AM
05/24/12 08:22 AM
Joined: Jul 2007
Posts: 1,682
Philadelphia
R
radar Offline
top fuel
radar  Offline
top fuel
R

Joined: Jul 2007
Posts: 1,682
Philadelphia
I think stock on a 750dp is 72/80 6.5pv

Re: What carburetor jetting as a starting point? [Re: radar] #1238655
05/24/12 09:18 AM
05/24/12 09:18 AM
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY Offline
Master
MR_P_BODY  Offline
Master

Joined: Jun 2003
Posts: 52,972
Romeo MI
Quote:

I think stock on a 750dp is 72/80 6.5pv




He needs to look up his carb number... they did vary

Re: What carburetor jetting as a starting point? [Re: MR_P_BODY] #1238656
05/24/12 04:07 PM
05/24/12 04:07 PM
Joined: Aug 2003
Posts: 43,223
Bend,OR USA
C
Cab_Burge Online work
I Win
Cab_Burge  Online Work
I Win
C

Joined: Aug 2003
Posts: 43,223
Bend,OR USA
Quote:

Quote:

I think stock on a 750dp is 72/80 6.5pv




He needs to look up his carb number... they did vary



The dash number makes a difference on the jetting


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: What carburetor jetting as a starting point? [Re: Cab_Burge] #1238657
05/25/12 12:26 AM
05/25/12 12:26 AM
Joined: Apr 2009
Posts: 3,415
Toronto
M
mshred Offline OP
master
mshred  Offline OP
master
M

Joined: Apr 2009
Posts: 3,415
Toronto
Hey all, thanks for the responses!

First off, I will have to look up the number on the carb...If I remember correctly stock jetting was either 72/80 as mentioned, or 75/80, with a 6.5 pv and I think 28 squirters. Either way I will look it up tomorrow.

I could definitely start where I am and jet up from there once I get to the track, but I figured if I could get a little closer before firing it up I would. The carb is absolutely stock, other than changing from pink pump cams to a blue one

And yes, this is the new 365" that is going in the scamp....Fire up is only a few days away now, not much left to do to finish it up.

Thanks for the help so far guys

Re: What carburetor jetting as a starting point? [Re: mshred] #1238658
06/01/12 12:17 AM
06/01/12 12:17 AM
Joined: Apr 2009
Posts: 3,415
Toronto
M
mshred Offline OP
master
mshred  Offline OP
master
M

Joined: Apr 2009
Posts: 3,415
Toronto
Hey guys,

so it has been a while since I last posted in this thread as I was so busy with other stuff on the car that I kept forgetting about this...I finally got around to it today though, and im ready to fire the car up.

The list # is 82751 and then underneath that there was another number 0840

Not sure where I can look these up??? Hopefully this will help with the starting point suggestions for jetting

Re: What carburetor jetting as a starting point? [Re: mshred] #1238659
06/01/12 03:44 AM
06/01/12 03:44 AM
Joined: Apr 2005
Posts: 12,271
Overpriced Housing Central
RobX4406 Offline
I Live Here
RobX4406  Offline
I Live Here

Joined: Apr 2005
Posts: 12,271
Overpriced Housing Central

Re: What carburetor jetting as a starting point? [Re: mshred] #1238660
06/01/12 03:45 AM
06/01/12 03:45 AM
Joined: Aug 2003
Posts: 43,223
Bend,OR USA
C
Cab_Burge Online work
I Win
Cab_Burge  Online Work
I Win
C

Joined: Aug 2003
Posts: 43,223
Bend,OR USA
I looked at Holley tech archives and couldn't find that carb. # there Sorry


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: What carburetor jetting as a starting point? [Re: mshred] #1238661
06/01/12 08:46 AM
06/01/12 08:46 AM
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
Mr.Yuck Offline
Not enough dumb comments...yet
Mr.Yuck  Offline
Not enough dumb comments...yet

Joined: Jan 2003
Posts: 24,562
Brookeville, Md
might like a little more jet but that's a good starting point. One easy way to find out...


[IMG]http://i66.tinypic.com/pui5j.jpg[/IMG]
Coming soon!!!!
Re: What carburetor jetting as a starting point? [Re: Mr.Yuck] #1238662
06/01/12 01:51 PM
06/01/12 01:51 PM
Joined: Jan 2003
Posts: 6,266
Renton Washington
T
Triple Threat Offline
master
Triple Threat  Offline
master
T

Joined: Jan 2003
Posts: 6,266
Renton Washington
I'd go up a couple just to be safe, but you probably aren't that far off.


-Dustin
67 Dart, 9 second, 392" G3 Hemi
68 Barracuda 340 F/SA
Re: What carburetor jetting as a starting point? [Re: Triple Threat] #1238663
06/01/12 02:27 PM
06/01/12 02:27 PM
Joined: Jan 2003
Posts: 2,931
P
Paul_Fancsali Offline
master
Paul_Fancsali  Offline
master
P

Joined: Jan 2003
Posts: 2,931
Small block Mopars don't need exceptional jet changes with a Holley esp DBL pumper . Keep in mind that carb is rich already. Stay with what you have and jet at the track after plug pull etc I would start with 70-71 frt and 76-77 rears and make sure your powwer valve is correct that makes a big difference. The squiters are little big in my estimation I would try 31-32s. Again use what the engine /carb want.

Re: What carburetor jetting as a starting point? [Re: RobX4406] #1238664
06/01/12 05:17 PM
06/01/12 05:17 PM
Joined: Apr 2009
Posts: 3,415
Toronto
M
mshred Offline OP
master
mshred  Offline OP
master
M

Joined: Apr 2009
Posts: 3,415
Toronto
Quote:

75 p
80 s

http://static.summitracing.com/global/images/instructions/hly-199r10319-1.pdf




LOL thanks Rob, your the man!

I thought that was the stock jetting, turns out I was right...Now, that being said, what does everyone think? Just start there, or jet up from now? Like I said before, im pretty sure last years combo wanted more jet, but I never got around to actually trying it with a busted dual feed line at the track.

As for squirters, 35's were the only size that killed the huge hesitation I had before with the stock squirters on tip in throttle

Re: What carburetor jetting as a starting point? [Re: mshred] #1238665
06/01/12 05:40 PM
06/01/12 05:40 PM
Joined: Jan 2003
Posts: 5,486
SoCal
Brian Hafliger Offline
master
Brian Hafliger  Offline
master

Joined: Jan 2003
Posts: 5,486
SoCal
Are you running a 1" open spacer under the carb?


Brian Hafliger
Re: What carburetor jetting as a starting point? [Re: Brian Hafliger] #1238666
06/01/12 05:46 PM
06/01/12 05:46 PM
Joined: Apr 2009
Posts: 3,415
Toronto
M
mshred Offline OP
master
mshred  Offline OP
master
M

Joined: Apr 2009
Posts: 3,415
Toronto
well I bought 1" that I bolted on yesterday, but the throttle cable angle is way off with it, so im ordering a new throttle cable bracket...For this week it won't have it, but once I get the new bracket im putting the 1" back in plus the cheater plate, so i'd like to jet it now for what it should be if I can avoid having to drain the fuel in a week just to jet up

Re: What carburetor jetting as a starting point? [Re: mshred] #1238667
06/01/12 05:52 PM
06/01/12 05:52 PM
Joined: Apr 2005
Posts: 12,271
Overpriced Housing Central
RobX4406 Offline
I Live Here
RobX4406  Offline
I Live Here

Joined: Apr 2005
Posts: 12,271
Overpriced Housing Central
Open spacer and a juice plate. Step up the jetting 2 on both sides to start, 77/82

I'd put the juice plate on first then your spacer.







Powered by UBB.threads™ PHP Forum Software 7.7.1