I need advice for a good street performance/economy slant 6

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krazykuda

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Hi everybody. I am having to learn about slant 6's as my ex's 64 Dart is broken down in my back yard, and I need to get it out of here as it is blocking the entrance to my back garage where all MY toys are. I have alot of experience on SB's, none on a slant 6.

We are going in two phases. One is a 49 k original mile slant 6 to bolt in and go for now. Meanwhile, we want to rebuild another for better street performance and economy to be swapped in later.

I have a 66 and 67 slant 6 along with a 64 slant 6 with a piston through the side of the block to scavange off of. We are looking for improved performance without sacrificing too much economy. What combinations should I be looking at?

I'm thinking of running 9.0 - 9.5 compression, double roller timing chain (if I can find one), performance cam (that still gets good fuel economy). What combinations have you tried, and how happy were you with the results? I have a very good head guy that can port my head and add hardened exhaust seats. Which year head would be the best to modify? Should I have him install bigger than stock valves while he is at it? I have read an article that stated the slant 6 responds well to opening up the bowls in the ports. My head guy is great at that.

I know there is alot of potential in the good ol' slant 6 (the leaning tower of power), I need your help and advice to get it out. :rock:

Thanks
 
for a milage motor i would stick with stock valve size buti would do some bowl blending to help improve flow... also install hardened exhaust seats if it is a 72 or earlier head

as for the cam figure a 200-210 duration @ .050, 320-330 lobe w/1.4 rockers, 106LSA

good compression 9.0-9.4

i would look into dutra duals or try to port out the factory exhaust manifold for improved flow also
 

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Remove the complete exhaust system and go with 2 1/4 inch pipe to your manifold with a good quit 273/318 muffler for some back pressure and defiantly get rid of the point system.
When you do the plugs use the NGK plugs and remove the washer if you have drool tube heads, this made a giant step forward for me krazykuda. It's all in my restoration thread.
I got allot of help from our members here.
 
I'm thinking of running 9.0 - 9.5 compression,
Both block and head can be milled to get you close to this. While upping the compression ratio will improve efficiency, it may be necessary to use higher octane fuel which is sufficiently more expensive to wipe out the savings created by the higher compression ratio.
double roller timing chain (if I can find one),
Cloyes makes one. There's a guy over on Slant6.org that does group buys. I got mine from him.
performance cam (that still gets good fuel economy).
According to the Mopar Six Cylinder book, the 72 and later stock cam is considered a performance grind. There are occasionally group buys over on Slant6.org for a Sig Erson. Last I heard there had been some unforseen circumstances of delayed delivery. Comp Cams makes a pair of bump sticks. Neither is very radical.
I have read an article that stated the slant 6 responds well to opening up the bowls in the ports.
You and I must be reading the same stuff. The Mopar book has some porting templates in it as well that may be of help to your machinist.
As for heads, suggest the 72 and later heads because they have the hardened seats.

Recommend switch from points to electronic distributor. The factory version or Petronix work well.


Good luck
 
Both block and head can be milled to get you close to this. While upping the compression ratio will improve efficiency, it may be necessary to use higher octane fuel which is sufficiently more expensive to wipe out the savings created by the higher compression ratio.

Good luck

i agree that running to high of compression that you will need better octane but i dont think anything lower than 9.5 will have any trouble on our crap regular... especially with the stock lazy curve... have to remember that with such a small bore and flat tops the plug is really the only thing left to cause detonation...(generally speaking)

ran 9.4 on reg with no issues... and its 110 outside with the engine @ 210... 32* locked out timing
 
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