Jetting

[cannucky]

A little confused by Holley's numbering system , the dyno sheet say's it's got 94's front and back and I think the jets were stamped 94 when I looked at them so does that mean they are jet #94 or .094 hole size ? If it's jet #94 it would explain my too rich problem cause that seems like a lot of jet for a 410 inch sb doesn't it .Getting ready to order some smaller jet sizes to tune with just don't know what ballpark I am starting in eh .

 

[jimjimjimmy]

I gota jet kit on ebay from #60 to #100 for cheap .just to give you a ball park idea my 520 hp 416 with a 950hp I use #68 primary and #78 secondary and it is still a tiny bit fat but nice and crisp .

 

[cannucky]

Thanks your right in the same ballpark as my 410 , a .094 hole size is I believe a # 82 or close to it and I am looking at dropping about 4 sizes , not sure if I'll get down to a 68 up front , what I have now made great power but has been really rich to the point of leaving a golden film on the back bumper and tail panel after a couple of thousand km's of cross country highway cruising to moparfest the past couple of years .

 

[mopowers]

Keep in mind the jet sizes do not necessarily represent the hole sizes in thousanths. Here is a Holley jets size chart. Notice how some sizes actually have the same hole size but a different jet number. I believe the jet numbers represent the flow rate. I'm sure other will chime in.

 

[cannucky]

Okay forget 94 I just pulled the bowls off and checked , it's got 77 in front and 79 in the back so I'm goingbto get a couple of sizes in the 72-74 range to try up front and put the 77 in the back

 

[70aarcuda]

What size carb is it?

 

[Fisher]

What is the dyno telling you it needs to have in the motor for air fuel ratio?

 

[justinp61]

I ran 72/80 in the 950 on my 408.

 

[cannucky]

Okay in order
A) it's a Holley hp950
B) I don't own a dyno so it's not telling me anything at this point , however when it was built Brian made several pulls after break in starting with 79/79 and 34 degrees total timing and ending with 77/79 and 32 degrees being the best of the lot .I ran it the way he shipped it until I popped a head gasket year 3 , at that point when we opened her up the pistons and heads were thick with crusty carbon , 2 years of fiddling with the carb and timing have only produced the same crusty interior so now I am going to re-jet it completely and was a little confused about holleys numbering system.
C) I am curious about which circuit is actually too rich in my setup since it didn't foul the plugs this bad before the blown head gasket but was crusty inside after a 1000mile cruise.
Ps thw blown head gasket wasn't a tuning issue it was the result of a demonstration of kick down linkage -yes it will kick down into 2nd at 95 mph but should you try it ? Uh No

 

[cannucky]

Thanks mopowers for the chart I'll saving a screengrab of it .

 

[Frank Mopar]

Here is an article on air bleeds but it also states best power and torque are at 12.5-12.8 range rather then 14.7. Just food for thought when you look to lean out

Tuning With Air Bleeds- Car Craft Magazine

 

[cannucky]

Here is an article on air bleeds but it also states best power and torque are at 12.5-12.8 range rather then 14.7. Just food for thought when you look to lean out

thanks I'll look into that , the link goes to a former ebay page

 

[nm9stheham]

What is the main use for this car? Does it do a fair amount of cruising or are you hard on it all the time? What power valve number is in there?

 

[cannucky]

it just bombs around town most of the year but the real problems show up after/during my annual cross country blast to moparfest ,3000miles / 5000km one way equals about 45 hrs of highway over about 4 days depending on traffic . Brian sent it to me with 6.5's front and back for power valves I swapped them for 4.5 's a couple of year ago when it was loading up at the lights around town .