timing help for a 396, please?? {long}

Bow_Tied · May 15, 2001

I have been following recent posts on timing and done a bit of searching on this topic. I understand the basics, but I am new at this timing busines, and was looking for suggestions from the experts.
First, my 69's specs:
396 (325hp) .030" over
forged alum pistons 10¼:1
stock heads (far as I know)
mild crane cam (I don't know the specs)
Edlebrock torker II (low-rise single plane)
holley 750 dp, mech 2ndaries
HEI, Accel super coil
moroso wires, NGK V-groove plugs @ .060"
M20, 3.07 gears

1) I know that this probably not the greatest combo, but it came in the car and I don't have $$ to upgrade now. I would like to set the timing as best as possible with what I have, of course none of the books have a 396 with HEI - so what #'s should I use? (I have a haynes, a chilton and motor book).

2) The car came with the vacuum advance line on the carb (passenger side, by front meter block). There seems to be little to no vacuum there at idle. There seem to be no other ports on the carb. I changed this to the port on the intake manifold immediatley under the carb, seeming to run better...Is this correct?

Your wisdom and suggestions are much appreciated.
Ron

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'69 SS 300 Deluxe / '71 Malibu 2DR HT
"Never let fear and good judgement hold you back."

Wooderson · May 15, 2001

I set my Big block at 12 before top dead center with the vacuum advance unhooked and plugged. After thats set, I hook the advance to full manifold vacuum, not a ported source of vacuum. Hook it either to the carb. or intake as long as it has vacuum at idle. At least thats what I do.

Mytmouse · May 15, 2001

Ditto the above although on my 70 I ended up at 13 degrees because it just seemed to run a little better there. My 67SS is set at 12* BTDC with vacuum disconnected and plugged. I think the 67 manual I have said set it at 4* BTDC but you will find that most people recommend between 8-12* BTDC and 36-40* total at about 2500-3000 RPM for better performance on BBC. I am not the expert in this area but I hav learned the numbers from those on this site that are.

BTW, I also had little or no vacuum on the port on the carb on my 70SS so I moved it to the vaccum fitting on the back of the manifold and it also ran better, so yes I think doing that is correct. Now I just need to fix the carburation/hesitation problem and I will be all set.

Good luck

Mytmouse

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67 SS396 350HP 4 sp 3:55 Posi Butternut Yellow w/Black Vinyl
68 RS Z/28 302 350+Hp? 4sp 4:10 Posi, Euro Red on Black
70 SS396 350HP 4 sp 3:55 Posi, Black on Black

Mytmouse A.K.A. Robert Stacho
ACES Member # 04359

[This message has been edited by Mytmouse (edited 05-15-2001).]

Bow_Tied · May 15, 2001

Thank-you gentlemen!! That is exactly what I did - changed the initial to 12° (from 30°!!!

) and boy she pulls a lot nicer now, particularily above 3000rpm. Next I will set my carb mixture screws with the vacuum gauge, hopefully that will help relieve some of the bog of the line..??

I am interested in any other comments on this or my carb settings as well etc. TIA.
Ron

[This message has been edited by Bow_Tied (edited 05-15-2001).]

[This message has been edited by Bow_Tied (edited 05-15-2001).]

[This message has been edited by Bow_Tied (edited 05-15-2001).]

snake · May 15, 2001

Yours is almost built like mine.This is my timing.12 degs at idel with vac line plug then plug to full time port had to make a limiter for vacume advance it was giving to much now with vac hook up it gives 8 degs for 20 degs at idel.I also installed an advance kit with one light spring and one heavey this gives me a nice advance curve from idel up.u should try using timing tape on the balancer or a timing light that is adjustable to set total timing around 34 to 38 mine is set to 38.What nozzel is in the carb.My holly has# 37 this is a good shot of gas for a good launch set float so it just barely drips out the sight hole and set mixture with a vacume gague boy i could go on but thats it for now.

good luck

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http:/hometown.aol.com/ddppell/myhomepage/profile.html
Don Pell 66 396 Beaumont.
Once bitten twice shy.
Don Pell 66 396Beaumont.
Once bitten twice shy

Guest · May 15, 2001

It would be nicer to have more vacuum advance at idle. The motor can stand more with no load. So, if you set it up with say 12 in the can then it would have 24 to 26 depending on initial. It will bust harder and if the mechanical comes in when it should the transition to full mechanical and no vacuum at WOT will be smooth.

Put a fairly larger squirter in the front and use the hi-po version with the hollow hold down screw. I used a 41 on a 368 motor but it was an 8156 annular discharge carb.

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Wally
www.muncie4speed.com
Gold #67
2001 Chevy Silverado LT
67 Malibu "Small Block" second owner
90 SS454 FOR SALE
71 Malibu "Small Block"

Bow_Tied · May 16, 2001

Thanks again guys!! I will have to do a tear down on the holley and do it proper...

Don, I hope to talk to you more about this on the weekend! I did just install a new moroso weight set and I used the medium springs. I am curious to know if your decision to use different springs was to find a happy medium between the spring strengths?

Any more comments are welcome

- Cheers for now...
R

timing help for a 396, please?? {long}

Bow_Tied

Wooderson

Mytmouse

Bow_Tied

snake

Guest

Bow_Tied

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