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MSD 83647 Heat HEI Ignition Module

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MSD 83647 Heat HEI Ignition Module
MSD

|

#54783647

MSD 83647 Heat HEI Ignition Module

  • Produces an incredible 7.5 amps of current
  • Enables you to adjust the rev limiter without removing the cap
  • Features an advanced dwell control for improved high rpm output
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$163.75

/each

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$181.95

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Product Summary

  • Produces an incredible 7.5 amps of current
  • Enables you to adjust the rev limiter without removing the cap
  • Features an advanced dwell control for improved high rpm output
  • The built-in adjustable rev limiter can easily be set externally
  • It easily installs to non-computer controlled (4-Pin) HEI housings

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Key Specs

D-40-43
MFG. Part #83647
BrandMSD
CARB EO#
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MSD 83647 Details

This all new Heat HEI Module supersedes the current PN 83645. Using upgraded components, the HEAT produces high output for stock and MSD applications plus has a built-in rev limiter that is more accurate and easier to set with the engine running.

Works with non-computer controlled (4-Pin) HEI housings.

  • Easily installs to non-computer controlled (4-Pin) HEI housings
  • Built-in adjustable rev limiter can easily be set externally
  • Advanced dwell control for improved high rpm output
  • The Hottest HEI Module you buy-period!
  • Produces an incredible 7.5 amps of juice!
  • Adjust the rev limiter without removing the cap!
  • Fits in stock HEI distributors

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Rebates

Holley Fuel Up Spring Savings Event 2026

Save 10% instantly on select products across the Holley family of performance brands during the annual Holley Fuel Up Spring Savings Event 2026. Instant rebate period runs from March 30, 2026 through April 19, 2026.

Warranty Information

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MSD 83647 Specifications

D-40-43
KEY SPECS
MFG. Part #83647
BrandMSD
CARB EO#
GENERAL
GTIN Code085132836475

Ratings & Reviews

4.2

14 Reviews

Overall Assessment

Customers consistently praise the product for its ability to enhance car performance, particularly by fixing high RPM misfires and stabilizing sparks to prevent plug fouling. The addition of a rev limiter was a widely appreciated feature. The majority of users experienced improved performance and found it simple to install. However, some wish it maintained a more stock appearance and were seeking further power enhancements. The product was preferable to comparable items from other brands, notably outperforming the pertronix flame thrower.

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4.2

14 reviews

5

8

4

3

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1

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Most Liked Positive Review

5.0

Guarnteed perfomance

With the OEM module installed I had a distinct miss over 6000 rpm. after installing this heat module, the miss went away, and in my opinion, the performance of my dirt track car improved slightly. My previous unit lasted me 5 1/2 seasons. Cant go wrong with this unit.

Most Liked Negative Review

3.0

Works well

Fixed my high rpm misfire. Only reason it gets less than 5* is that it doesn't appear stock. It has a extra wires and if they pull the cap its clear this is not OEM. This same part inside a stock looking module would be better. That being said, the pertronix flame thrower failed on me after two nights which is what lead me to this. Happey with it, bit I wish I could have this performance in a stock looking package.

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I would not buy this again

1.0

23 days ago

Bob

Ryegate vt

Verified

Installed did not start after ended up buying a mds rev box for her worked so much better

Would Not Recommend

Great replacement

4.0

3 months ago

Sam

Arkansas

Verified

Great replacement part

Would Recommend

Great quality and ease of installation

5.0

a year ago

Spaaz

Saint clair mo

Verified

Swapped automatic out for 4 speed muncie needed a rev limiter the instructions were easy to understand and instalation was easy.

Would Recommend

Great product

5.0

2 years ago

Mike

San Diego

Verified

This was one of the last things I could add to my chevelle to get a bit more power and a rev limiter. I would buy this again if I had another car to put it on

Would Recommend

Easy to install, works like it should

5.0

6 years ago

Romeo

Arkansas

Verified

Let's go racing!!!

Would Recommend

Works well

3.0

7 years ago

Jr

A local dirt track

Verified

Fixed my high rpm misfire. Only reason it gets less than 5* is that it doesn't appear stock. It has a extra wires and if they pull the cap its clear this is not OEM. This same part inside a stock looking module would be better. That being said, the pertronix flame thrower failed on me after two nights which is what lead me to this. Happey with it, bit I wish I could have this performance in a stock looking package.

Would Recommend

Worked as designed

5.0

8 years ago

pem

colorado springs

Verified

Quality product that worked

Would Recommend

not worth the hype

3.0

9 years ago

msdstinks

usa

Verified

so far no advantage to a stock GM module on a 500+hp carburated car... except having a rev limiter. car might start a very little bit better but idle seemed weaker & no noticeable difference in any RPM up to 6000 vs the stock module. makes for an expensive rev limiter!

Would Not Recommend

this is and easy to install rev limiter

4.0

10 years ago

rich n

brainerd mn

Verified

Good product.

Would Recommend

Great Product

5.0

11 years ago

Bryan50

Lee's Summit MO

I drive 4 mile to & from work, had trouble with fouling plugs on 350 Chevy street car. Put this module in with an HEI Blaster Coil and stabilized spark, no more fouled plugs.

Would Recommend

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