I've been hearing mixed answers on how high any engine with a standard HEI will go...I've heard they start breaking up at 4500, then I've heard 5800, etc. But for an engine (big block) that's going to see 6500 rpm max, what would you recommend?

I am almost sure I will not need any MSD stuff am I right?

My stock HEI goes to 6000 no problem,and I do not have any spark boxes.It'll rev higher,but my cams rpm range is 2-6K

The only "mod" is an Accel in cap Super Coil
IMHO and experience,hi-po ignition parts are the most overhyped components out there,especially for a 12-14 second street/some strip car.
Most times when an engine "breaks up" or falls down is either from a poor fuel system,bad valve springs,etc. or trying to rev under load to 6K + with highway gears.

I agree with mr4speed. I've dynoed several engines with stock HEI's and none of them had ignition issues. The engines went up to 6000 rpm due to the cams they used. If you're building a 8000 rpm screamer you probably want something better, but for a <6000 rpm street/strip car a stock HEI is all you need.

If the distributor is in good mechanical condition and you have the good GM "990" module, or the Napa's best module, a HEI will go to 5500 easily. Mine always did.

Avoid the aftermarket stuff; modules, coils.

Mike

We dyno a local dirt track race car that runs a DUI HEI setup to 7500+ rpm all the time.

The engine I plan to build is going to see 6500 max and that will be on race day of course.

I was planning on using Mallory's HEI, p/n MAA-8548201C. It sells for $159 thru Summit racing and it includes cap, coil, rotor, module and vacuum advance. I think the coil is rated good up to 5500 rpm. Now of course Mallory also has a high output coil that's supposed to be good from 4000-7000 rpm but the engine I'm going to build has a cam that sees 2300-6500 rpm as it's power range. So now I question if either coil will effectively produce enough spark for my intentions. :confused:

Originally posted by mr 4 speed:
Most times when an engine "breaks up" or falls down is either from a poor fuel system,bad valve springs,etc. or trying to rev under load to 6K + with highway gears. Wouldn't the improper valve spring do the same as a bad valve spring? I think you are referring to "floating the valves" aren't you?

I think he means improper spring (too weak) will cause valve float. I think thats's my problem as well.

The very early GM HEIs had some module problems and the aftermarnet guys have played on it ever since. With the 990 module and proper setup, the HEI has handled the 6500+ rpm of our L78, never missing a beat. It's all you will ever need for a street car.

my Nova saw 7400 a few times with a stock HEI that had an MSD hei module in it.

I'm most likely going to stick with an aftermarket HEI such as the Summit one that sells for $149 complete or the Mallory one for $159 complete. I'm guessing they probably have copied GM's design and may have even made some improvements.

Originally posted by JimChevy:
I think he means improper spring (too weak) will cause valve float. I think thats's my problem as well. Right, I was just wondering if the improper valve springs will do the same as a weak valve spring.

Originally posted by JimChevy:
I think he means improper spring (too weak) will cause valve float. I think thats's my problem as well. ..that exactly what I mean smile.gif

I had a 71 nova years ago,mild 383,th350,stock HEI dist.no msd or anything else,and I shifted the motor at 7000 rpm's while making a pass.

If the HEI is in good mechanical shape including the advance weights, the module is the limiting factor. The cheap aftermarket stuff is crap and will give you problems most times after 4500rpm. The GM module and some of the more expensive aftermarket modules will get you where you need to be.

As far as the Summit HEI, make sure you try it out and check the total timing. A buddy of mine bought two of those before Summit replaced the second one with a Mallory. They were retrading the timing rather than advancing it as RPM increased. We couldn't figure out why. The mechanical advance looked like it was built correctly. When we called Summit on the second one, they admitted they were having a problem with those and offered a Mallory as a replacement. It worked fine.

Thanks Troy. I have never used the Summit one before but I have used the Mallory one and it worked great.

I should add that not all the aftermarket "good" stuff is good either. A pertronix module that I used a couple months ago for another friend (I have too many "friends" since I built my shop) didn't work past 5000. It cost $39.00. It's basically junk unless you are driving a truck with a grunt motor in it.

Troy.

JYD, I had 6000 rpm on stock HEI from a truck.
Was getting some break up and starting problems.
Put in an MSD module and it was a little better.
Problem turned out to be the 12 vdc resistor wire from the old points distributor. The stock module probably would have been fine.
I replaced all with an MSD since though. I wanted to better control over my advance and curve.


Troy, Your motor combo is nearly same as mine.
You have (With old perf. rpm cam ) in your sig.

What is that all about and are you running faster than 12.74 now?

Dave

sorry, not trying to hijack post here. ;)

I ran exactly the same with the new CAM. Converter was crap. I have a new BTE converter in there just haven't found the time to get back to the track and see what it does for me.

What carb are you running?

Troy.

Originally posted by Troy70SS:
I ran exactly the same with the new CAM. Converter was crap. I have a new BTE converter in there just haven't found the time to get back to the track and see what it does for me.

What carb are you running?

Troy. Thats why I asked, was the cam difference.
I was thinking of going to a hyd roller, but havent really picked out a cam yet.

I am running a Holly 750 DP.
I think the it could use an 800 or 850 though.

I agree with the bigger carb. I am going to try one of the Proform Main bodies. I already have it but want to run the car without it and then try it with it. With the time I have, it may take me 6 months to get that accomplished.

Hey - where is Burton. I am originally from south of Youngstown, OH.

Troy.