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MSD 83647 Heat HEI Ignition Module

MSD 83647 Heat HEI Ignition Module
Product Video
MSD 83647 Heat HEI Ignition Module

Click image to enlarge

Follow along as an MSD HEAT HEI Module is installed on a classic HEI distributor.



Q & A

What's in the Box

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

547-83647 Instructions (PDF)

MSD Tech Bulletin (PDF)

MSD Rebate (Link)


Customer Reviews

Rated 5 out of 5 by 4 reviewers.
4 reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star

Lee's Summit MO
Product Rating

Great Product

November 09, 2014
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.
Yes, I recommend this product.
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Verified Purchaser
wichita ks
Product Rating

great product

May 27, 2014
It is a great product especially if you need the plug on the end for dist.
  • wiring plug
Yes, I recommend this product.
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Cincinnati, OH, USA
Product Rating

Guarnteed perfomance

May 14, 2014
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.
  • increase the burn
Yes, I recommend this product.
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Verified Purchaser
Ironton ohio
Product Rating


August 24, 2012
Put the module in my dirt track car. Very easy installation of this part, improvement on performance and no need to change limit pills. Can't find one negative thing to say about the module great product
  • Easy To Install
  • Improves Performance
  • Provides Accurate Readings
Yes, I recommend this product.
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Page 1 of 1

Product Q&A

2 questions : 2 answers

how do you reset the limiter to different settings once its installed

1 answers
April 15, 2015

how do you reset the limiter to different settings once its installed


April 16, 2015
Page 2 of the instructions gives a step by step process for setting the rev-limiter. You can see the instructions here:

was is the rev limiter on this modual set to is it adjustable and what is the rev limit?

1 answers
April 13, 2015

was is the rev limiter on this modual set to is it adjustable and what is the rev limit?


April 14, 2015
This module does have a built in rev limiter. See the instructions in the link below for the procedure to set and check the rev limiter.
Page 1 of 1

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