911 SC with Webers, I have questions

[confused]

I have a 83 stock SC engine with new webers, MSD, 1-5/8s headers into a stock muffler.

Can anyone tell me why a early (78-79) SC distributor is better than a 80-83 dist when using webers? I was told this was so. If so does anyone have one?

I do not have the vacume advance hooked up. I was told to just set the total advance to 35 degrees, is this correct?


Weber question: does anyone know about how many turns the weber idle screws go out?

I am going to add 911 S cams and JE pistons later on. This does about 260hp?? Can anyone give me any other good power hints?


Thanks for any help

[dean]

Back in the dark ages when I used to work on carbs, we used to start at 1.5 turns out. Then you go from there.

[dd74]

If those pistons take the SC motor to a 3.2 short stroke "maybe" you'll make 260. Put a Carrera crank in, then for sure you'll have 260...out of a 3.4.

[cstreit]

Can anyone tell me why a early (78-79) SC distributor is better than a 80-83 dist when using webers? I was told this was so. If so does anyone have one?

- The advance curve was a bit more aggressive.

I do not have the vacume advance hooked up. I was told to just set the total advance to 35 degrees, is this correct?

- Thereabouts is correct. You'll end up with about 10 degrees at idle or so, but keep an ear out for pinging... If none, you're okay.

Weber question: does anyone know about how many turns the weber idle screws go out?

- PMO recommends 2, but I found this to be too rich, I start with one, but remember that each carb can be slightly different and you need to tune and sync them. Check out: http://www.pmocarb.com/installation.htm


I am going to add 911 S cams and JE pistons later on. This does about 260hp?? Can anyone give me any other good power hints?

That's probably a bit optimistic with the heads... You'll be losing power because of the port sizes for the later SC motors are a bit small for the S cams and higher compression... Plus you'll run out of revs quicker than yuo'll run out of power.

Honestly the best recipe for power is transmission work first, then the motor later...

[confused]

I was told by an optimistic POC race prep mechanic that I could have 260hp... I think that may be with the 78-79 SC head with 38mm ports.

All of this is in a 914-6 with a stock 901 gearbox. I was going to add a Quaiffe diff and maybe a billet intermediate plate (although I am told by some that the billet plate is needed only after 300hp). I guess I will need to change the gear ratios around a bit (any recomendations for a street driven car). What else can be done to the transmission?

Oh ya Cstreit, I think you were the one that told me 35 degrees total advance, thanks.