[bigblockv6]

No matter which of these two brands of HEI you go with both will require modifications to fit the GMC V6 , of what includes having a collar machined and retrofitting the stock V6 distributor gear to the new distributor, All of the procedures are in Jolly's website. What I can tell you about ACCEL is it's own by Prestolite who also owns Mallory distributors and Mr.Gasket. Prestolite did manufacture their own distributor back in the 60's and early 70's for Jeep and possibly Chrysler. If your looking for a straight bolt in HEI there is a vendor on ebay known as HEI Dizzy that makes a billet HEI specifically for all GMC V6 engines. I've also found the right type of spark plug for the .060 gap required for the HEI that's fits the long reach application of the V6 which I'll be trying out today and it's the AC-R44XLS6, if AC is not your choice of plug this number can be cross linked to other brands.