MSD Corvette HEI distributor $360
MSD controller $170
MSD Blaster coil $60
Heli or spiral wound race quality spark plug wires $100.

 

That adds up to $$$$! HEI Tach drive units can be had for $150.00 ...all self contained. Mine has provided me exceptional service. Installation was a snap, one new 12v and new set of HEI plug wires...connect tach cable...your done!

 

i just fought the same battle...i got rid of the points and put a pertronix electronic system. it fits under the oem dist. cap and works beautifully. btw, i also put in the pertronix coil. the elec. replacement was about 80 from ZIP corvette and the coil about 35. made a huge difference in my 74.

 

what's the benefit of locking out the advance?

 

No advantage in any car driven on the street at all.

 

Tach drive HEI!!!!!

 

First...a good stock HEI will work incredibly well. Gm did a great job on them. I've run stock ones with 2 stages of nitrous to 7500 rpm with no issues. Lots of advertising hype leads people to doubt them.

The Pertronix work great too and fits right in your stock dist.

The Crane version was nice..but the little internal rev limiter was a POS.

All that said...GOOD points....not the junk that is usually sold, will run forever with no need to live with a dwell meter in the glovebox. The average parts store points wil move around and be all over the place after each 7000 rpm blast. If you can find the old Delco D-112's they worked great....

I had fantastic luck with Accel points. They were absolutely rock steady and didn't wear. They cost $15-$20 a set....but it's worth it. I literally ran a set for 7 years with lots of race and street miles on them and they still were fine.

I also did a back to back test...sorta by accident with them on my 540 on the dyno. Usually I would just use the *house* locked out dist. on the dyno because it was already prewired etc. The last time I took mine to be tested their MSD dist had barfed..so we threw my points dist in it to see what happened. The previous version of the motor peaked around 6500 rpm and it had worked fine. We started testing and it was great until about 6900-7000 rpm....the points were starting to bounce a little. Again...these were 7 years old!! It was still making 810HP at that point....and still climbing. I went down the street and borrowed an MSD dist from another dyno shop and came back and installed it. The good news is that the MSD dist let it spin higher and it ultimately made 825HP at 7400 rpm. But up until the point bounce issue...the MSD did nothing for power at all...not one more. I have no reason to expect that a NEW set of points would have been able to spin 7500 rpm and do just fine too.

I love MSD stuff....the MSD box will help low speed driveability with big cams and carbs...but not really do much for power. The Dist itself won't do anything..and you will need to make sure you change the bushings and springs in it to get curve right. But it IS a good part.

I guess what I'm saying...is if you just want to do something..it's a great change....but don't expect power to improve really...or if you just install a good set of points for $20..you can spend money on something that will actually help car run better.

JIM

 

All one needs to know is to read 427`s reply directly above.

well done Jim,...

 

that looks like the dragon fire in which i spoke

 

on my 74 i replaced the old points distributor with a new msd .... i have the one with the external coil because needed the room for breather clearance .... with the 74 you have a tack drive dist ... there's a mechanical cable coming out of the dist to run the tack .... because my tack was damaged and needed replacing i replaced it with a 75 electric tack and ordered the msd tack without the tack drive .... wire hook up is simple, works really great and now i have no tack drive issues ... 75 tack looks the same as the 74 .... no points and condenser to adjust makes life a whole lot sweeter...leaves time for driving and fixing other problems.... thats my 2 cents worth

 

Thanks guys, guess I'm going to hei. Noticed that Mike Ward didn't think pertronicks wasn't the right way to go. Or did I misunderstand?

 

Here is one of the cheap ebay "made in north america" tach drive HEI's I ordered recently just to see how they are. Surprisingly looks quite cleanly made. Might give it a try in the summer. Currently the car has a points dist + MSD 7A.

 

No, a poster above stated that a pertronixs conversion kit= HEI. This is not correct.

If you want to get a points eliminator kit like this unit or a Crane, that's your choice. Also realise that no ignition system is going to give you more HP over a properly set up stock system.

 

Did he? I didn't read it that way. He just stated he converted a points dist to pointless. Whether it was 100% relevant to points or HEI discussion is another matter but I must confess that when I saw your reply my 1st thought was "what a smart .ss". But now I see that you intrepeted his text differently than i did and it makes sense.

I've converted few points distributors with Pertronix Ignitor kits and they all worked perfectly. An good option between points and HEI. Only takes few minutes to install. HEI conversion is a bit more involved. Then there is also the points + MDS box -option, again more wires to connect. With this option the points only work as trigger and their life is greatly extended.

 

Should spark plug gaps be increased when changing to HEI?

 

Check post #6 on this thread.

 

Your points had the + wire to the coil, that on my '72 was a wire with white cloth over it, that went down to the starter P terminal...cut that off, the other black wire is kinds stiff compared to others like it, because it's a resistance wire to limit the points current to keep from burning them out....so Chrysler back in the day used a white resistor instead...so you follow that black wire back to the bulkhead connector...remove that tab, and solder a pink wire to it, replace everything, and it's now a hard +12 source to the HEI BAT terminal....the tach terminal goes to a 'tach filter' you can find a wiring schematic here for that, and then into the 75-77 tach replacement....or you can go aftermarket and have no tach filter....I THINK GM used that tach filter crap for RFI suppression in their AM radios of the day......hence the placement on the engine, instead of inside the tach....

 

Excellent info, thank you!!

 

I'm not sure I understand the "resistance wire". Is that a wire from the coil to the distributor? Or is it one of the wires in the distributor? (I'm hoping I didn't screw something up!)

 

It is in series with the keyed on hot to the coil.,