HEI Advance Curve

[Grim 82]

I am using a new MSD Streetfire HEI in my 350. The engine is stock besides the cam, which I was told is a low rpm, high torque cam. I am running about 14 degrees base timing and it makes decent power with no pinging. I have been told that the streetfire only delivers full mechanical advance when you get into the 5000 rpm range, and that the adjustable vacuum canister is not actually adjustable by faulty design. The solution that was offered was to replace the springs and possibly the plate, and the vacuum canister.   Can anyone verify this?   My highway cruising rpm seldom goes above 2500, and I don't wrap it up too tight between shifts.   Should I look to replace the springs and get the curve closer to "all in by 3000" or so?  It's an 82 K10 with an SM465. Any help is appreciated.

[Donut]

I don't have that dizzy, but how is the vacuum not adjustable by faulty design?
IMO, verify what your distributor is doing, either with a dial-back light or a standard light and a timing tape.  Then decide what you want to do.  Changing weights and springs made a world of difference in my case.  Your results may vary.  My e-bay dizzy wasn't "all-in" by 4000, it was still creeping @ 4500.

http://www.73-87.com/7387garage/drivetrain/timing101s.htm
http://www.73-87.com/7387garage/drivetrain/hei.htm

I would think MSD has a manual that would cover all this also.

[VileZambonie]

That distributor is basically a stock replacement. It's not going to do you any favors at 5,000RPM much over what a stock tuned HEI would do. You have much better choices for a performance distributor although for your application this one should be fine. Advance Kit PN 8428 should help as well as using an advance timing light like donut said to further dial it in.

[Grim 82]

Thanks for the replies. The faulty design was one guy's opinion. I was just curious if they are notorious for going bad or if this guy was just trying to sell me parts. You are right I need to invest in a dial back timing light and verify what I have going on. The parts store didn't have the MSD kit PN 8428, but they said the Moroso kit PN 72300 should be the same thing, so I picked it up. Will this kit work?  Should i use the plate & weights from the kit, or swap only the springs?
Thanks

[Grim 82]

I installed the Moroso kit and used the lightest weights. I bought a dial back light and still have to fine tune it all. So far the throttle response is greatly improved and it runs alot stronger. Thanks for the replies.