12 Second N/A Slant 6?
Now, can we add more lift by going to (affordable) higher ratio rockers?
Is there any way to modify the stock rockers?
We don't need exotic roller rockers for 5500 RPM so a simple 1.6 or 1.7 ratio rocker would be nice.
Good luck at finding high-lift rocker arms for a slant six. There are some 1.6:1 forged aluminum units available that are really nice, but they are expensive.... around $700.00 I think.
I don't have that kind of money, so I attempted to modify stock ones by removing a slice of material .110"-thick from the body of the arm on the pushrod side of the fulcrum and re-welding the two pieces back together. I haven't run them yet, so I can't say if the operation was a success.
I first took them to a heat-treating facility and got them annealed (they are case-hardened at the factory) so they could be more easily machined and welded (T.I.G.'d.)
I did some measuring and learned that to achieve a 1.6: ratio by removing material from the rocker and pushing the two pieces back together and welding them, I'd need to take out .110" of material.
I bought a steel 4" metal-cutter blade (about $100.00) of the correct thickness and chucked it up in a vertical mill (Bridgeport-style) and fabricated a jig to accurately hold the rocker arms for the cutting process. There is a photo of this jerry-rigged jig in the link, below.
Once the cut was made, the two pieces were welded back together and it's back to the heat-treatment shop for a return to the original hardness, an absolutely-necessary step.
The car is a turbocharged slant six with a 5,500-rpm redline and the cam is a mild one (219/210 @ .050"-lift with .484"-lift with stock rockers) so a lot of val spring pressure is not necessary. We run 340 outer springs with a small, pretty weak, inner for a total of 135 pounds on the seat and a little over 300 pounds at full lift. I am hoping that won't break these welded rockers.
Here's a link for you that shows the finished product and a picture that shows where the cut was made. It's a simple process.
http://www.forabodiesonly.com/mopar/showthread.php?t=233534
Good luck!:blob:
