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Discussion Starter #1
Ive been doing some reading about recurving the DS II distributor and been trying to gain as much information as I can to make a educated decision on initial setup if I even need to make adjustments or not.

First off the engine as will be built is as follows.

306 CID
AFR 165 Renegade heads 58cc chamber
hedman street headers for truck application
Edelbrock Performer intake
1" phenolic spacer
600 cfm summit carb
Scorpion 1.6:1 roller rockers
Crane TruckMax roller cam 216*/224* @ 0.050", 0.520"/0.542" lift, 112* LSA, 107* center line
9.5:1 compression

Aside from that this is in a '82 short wheel base flareside truck with a C6 transmission and a 9" rear axle. the C6 transmission will receive modifications itself as well as an axle ratio change from 2.75:1 to 3.25:1 to offset the 31x10.50-15 tires.

With all that said I generally wont be towing with this truck but there might be times when I will need to tow so I want to take this into consideration for the recurve to find a middle ground if possible.

From what I have gathered so far from online and from first hand sources from engine builders I know, I should be shooting for a total advance of 32* to 36* max and that it should be all in by 3,000 rpm.

Problem is though when reading the Crane Vacuum advance kit instructions online it states for truck or heavy towing applications one should shoot for 3,500 rpm where the timing is all in.

So which way would be the best starting point? 32* total advance all in at 3,500 rpm? I don't know where the shift point will change on the C6 with a rv/towing shift kit installed along with the wide ratio planetary gear set but currently stock its 4,500 rpm. I hope with the axle ratio change, the converter change, and the shift kit would get me to a 5,000 rpm shift point for passing gear.

Looking at my old notes I see I was advised to set the mechanical advance on the slot between 10 and 13, remove 1 heavy spring and install the mr gasket advance spring and then to use either the smp or bwd vacuum advance and set it to around 6-8* advance with the initial at 12* and total of 32*.

But that was also on a different setup than what I have picked out as of now after learning more on the subject matter but still not fully sure where I should set this dist at for starters. Im sure the stock set dist will not perform properly with all the changes I have made from a stock 302.
 

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first off don't include the vacuum advance in the mix. 32*-36* all in by 3500 means initial +mechanical. with vac adv., could be around 52*
 

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Discussion Starter #3
first off don't include the vacuum advance in the mix. 32*-36* all in by 3500 means initial +mechanical. with vac adv., could be around 52*
Really? From what I have always heard small block fords do not like more than 32 - 36* total advance anything more causes over heating and other problems.

That's why I am trying to dig as much as I can to find out all I can as I have a new dorman dist with a steel gear for my roller cam and before I install it I am contemplating pulling it apart and playing around with the mechanical advance making changes and give it a try.
 

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sbf aren't special . 32*-36* is normal for most engines. the timing is important under load. vacuum advance is not involved under load. it is only for gas milage
 

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Discussion Starter #5
sbf aren't special . 32*-36* is normal for most engines. the timing is important under load. vacuum advance is not involved under load. it is only for gas milage
So basically set it up to have some where around 32 - 36* total advance without vacuum advance and use the spring set to get it to be all in at 3,500 then?

The Crane vacuum advance kit I am looking at on the instructions it tells you the spring setup and it allows you to set it up for 2,600 RPM, 3,500 RPM, or 3,800 RPM.


load wise I couldn't say what load would be placed on the truck. With the new motor I might floor it and hit passing gear quite a bit till the novelty wears off and then it will be driven like a regular truck with hitting passing gear from time to time. No plans to pull a trailer with the truck but I might. I keep thinking about getting some kind of boat later on after I get the truck squared away and all my other projects finished.
 

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Discussion Starter #7
yep, go for the 3500
Thanks for the reply. I don't know if I can get it to 3500, it does have a small disclaimer I see now in the instructions that state the rpm may vary from dist to dist. Will just have to be something I play with.

I just wish I knew fully why the engine builder I know why he finds how much vacuum it takes to get the engine to hit the 32-36 timing range and he stakes it so vacuum advance wont go past 32-36.

From my understanding zero load you can have almost unlimited advance as there is no load. Might have to talk with him again one day and try and get more information out of him.

All I know is I am waiting for a good sale from summit to buy a large chunk of what I still need to get which also includes the Crane vacuum advance kit.
 
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