adjusting my vac

[SRT_DSTRHOLC]

Im trying to adjust my vac...i cant get higher than 5 but the needle is moving like crazy....when i put a higher pv in like a 6.5 it steadys out a bit and then likes to be put leaner...but with the 4.5 in it wont steady out...its a 750dp with 74 jets up front and 82 in the rear...do you think its a leak?

 

[70aarcuda]

went you hook a vacum gauge you only get 4.5 inches?

is the timing set correctly?

how big is the camshaft.?

 

[SRT_DSTRHOLC]

i get like 5 but the needle is moving crazy from 5 to 3 and timming is 18 initial with 36 total.....its 306duration 260 at 50 .575 lift

 

[70aarcuda]

360 @ 50 ?

try again.........

260 @ 50 ??????

 

[SRT_DSTRHOLC]

opps yes 260

 

[Longgone]

360 @ 50 ?

try again.........

260 @ 50 ??????

:-D That`s funny, the valves never close..............:munky2:

 

[moper]

You dont want the PV open at idle. Never. And becuase you didnt say... is this in gear or out of gear, or a 4sp? What is the idle speed? This is a 360, right?

 

[SRT_DSTRHOLC]

this is in gear, out of gear i get like 10 steady...automatic..idle speed out of gear is 850-900 and in gear it drops to like 600-550

 

[70aarcuda]

what kind of converter do you have?

 

[SRT_DSTRHOLC]

bte 3400 or 3600 one of the 2 why?

 

[Longgone]

Have you checked around the carb and intake for any leaks?

 

[SRT_DSTRHOLC]

im going to do that tomorrow when i get my battery charged

 

[Longgone]

That`s a pretty stout cam, I wouldn`t expect much more than what you`ve got out of it now. Maybe 12 in.? Do you have power brakes?

 

[SRT_DSTRHOLC]

i get 10 while the car is in Park not in gear just to clear that up, thought im suppose to tune it in gear?

 

[70aarcuda]

well..i am running 3.5 pv in my 750 dp with 260 @ .050

but it is not a street car...so the idle is set around 1200 rpm

 

[SRT_DSTRHOLC]

ahh ok do you have another one of those? maybe ill order one

 

[Johnny Dart]

i get 10 while the car is in Park not in gear just to clear that up, thought im suppose to tune it in gear?

To test vacuum: Auto in gear 4spd in neutral.

74 & 82 jets ? Who thought this was a good idea ?

I take it you have a 4160 750 Holley ?

To start,you need to go back to baseline on your carb. jets/power valve.
Adjust your floats correctly,proper a/f adjustment (1 1/2 turns out)to start.
Sounds like you have your carb way out of wack.

Once you are back to baseline,warm the car up,set your timing between
10-12 for initial. Set your idle between 800-900 in gear. Now take your vacuum reading,and let us know what you have.

 

[70aarcuda]

ahh ok do you have another one of those? maybe ill order one

yeah...i do...but i aint going to send you one...LOL

 

[SRT_DSTRHOLC]

this isnt a stock motor john...the carb was built by BIGS carbs...Thats how he has the jets setup..power valve in the front and none in the rear...it has a HP center with adjustable bleeds...im going to BUY a 3.5 since aar doesnt want to sell one..but ill let you guys know how it goes

 

[70aarcuda]

this isnt a stock motor john...the carb was built by BIGS carbs...Thats how he has the jets setup..power valve in the front and none in the rear...it has a HP center with adjustable bleeds...im going to BUY a 3.5 since aar doesnt want to sell one..but ill let you guys know how it goes

working out of town.....lol...

 

[SRT_DSTRHOLC]

ya, i need it ASAP, its like 10 dollars but its ok

 

[crackedback]

Not enough initial, it will probably want 20-24, maybe more. My 340 with a 214/224 cam wants 15-16*. Keep cranking it in until it kicks back on the starter when hot. That will help with your idle settings.

You'll have to limit the mechanical more to get your total number correct.

When you drop it in gear does the timing change?

 

[SRT_DSTRHOLC]

it has the black bushing in it...so your saying 20-24 intial with 36 total?

 

[Johnny Dart]

Wow,you guys running some timing !

Sounds to me if mr Bigs set me up a carb I would be talking to him.
What power valve did your carb from mr.big come with ?

With that cam I would think around 8-10 vacuum. So 3.5-4.5 on the power valve.

 

[SRT_DSTRHOLC]

4.5 still seemed too much im going to get a 3.5 and see what that does.

it came with a 4.5 but that was for a different cam