1997 V-8 Vortec Distributors

[Schurkey]

Tried searching this forum, got no appropriate results.

Bought a '97 K2500 7.4L with a dead miss in #8. Too cold, too snowy to lift the hood and diagnose--and no garage. Figure I can't go wrong ordering tune-up parts as I'll need them sooner-or-later.

Looking on Summit, I see Vortec-looking distributor caps and rotors advertised for a 5.0 or 5.7, but NOT for a 7.4.

WHAT IS THE DIFFERENCE between SBC Vortec caps and rotors, and BBC Vortec caps and rotors?

Also looking on Summit at complete Vortec distributors. Again, some are listed for 5.0--5.7 SBC and others are listed for 7.4 BBC, can someone explain to me what the difference would be?

I can't think of anything that would change or be different between SBC and BBC.

 

[454cid]

I do not know. I think Delphi had different part numbers for distributors, too, but then on ebay everything "fits" everything.

Typically Delphi or AC Delco are the recommended caps to get anyway. Other brands are reputed not to last long on our distributors. I've only changed my cap once...or had it done, actually. I provided the OEM parts that I got from a local dealer.

 

[Supercharged111]

Rock Auto has different part numbers for both too.

 

[wheelman]

If the engine has the crab cap.they should be the same.i learned my lesson.trying to use

A aftermarket cap on my 1996 350R vortec.got where it would not run right.when it rained

It would not fire up and run at all.i went to the dealer and paid the extra few dollars.got their cap and rotor

All starting problems went away.

 

[98 Nitro]

Ya the Vortec sbc/bbc trucks use the same cap.

 

[L31MaxExpress]

Ya the Vortec sbc/bbc trucks use the same cap.

Same cap, same rotor, same crappy plastic distributor and the same wear prone gear.

 

[Schurkey]

Got a reply from Summit--they're admitting that their cap and rotor combo which is listed only for small-blocks will also fit the 7.4L. I asked them to also update their application guide, and they have not done that (yet, at least.)

https://www.summitracing.com/parts/sum-g5225bk

They have a Summit-branded distributor for Vortec V-8s, one part number for small-block, one part number for 7.4. I'm kinda wondering if the distributor is the same, but they want to keep track of how many folks are buying them for small-blocks vs. how many are buying them for big-blocks.

https://www.summitracing.com/parts/sum-850098

https://www.summitracing.com/parts/sum-850099

In the end, I bought ACDelco D329A cap and D465 rotor from Amazon at a better price than the Summit combo.
https://www.amazon.com/gp/product/B000BYD3RC/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

https://www.amazon.com/gp/product/B000BYGD2O/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

 

[Schurkey]

While it still seems to me that the 5.0, 5.7, and 7.4 Vortec distributor caps and rotors are interchangeable, there IS a difference between the "small block" distributor and the 7.4L distributor.

That difference is a "Thermal Insulator", as described in the 1997 C/K service manual section 6D4A-2, and illustrated on the next page 6D4A-3. It's used only on the 7.4L distributor, not the 5.0L or 5.7L.

This "Thermal Insulator" appears to be some sort of insulating washer on the lower part of the distributor, above the distributor gear. I have no information as to any other difference--such as a shorter housing to provide room for the Thermal Insulator.

Wild Guess: The Thermal Insulator washer takes the place of the multi-piece thrust washers in a regular distributor. In other words, they removed the ordinary metal thrust washer, and installed a ceramic or plastic or Kryptonite washer instead, and there are no other differences.

Second Guess: The Thermal Insulator is only important in vehicles that get WORKED HARD and therefore have high oil temperature.

Third Guess: The Thermal Insulator isn't needed on aftermarket aluminum-bodied distributors, only on the plastic housings of the OEM distributor.

Someday, I'll yank the distributor out of my 7.4, and post some pics. Don't hold your breath waiting for them.

[EDIT] Oh, yeah...my dead miss in #8 turned out to be a cracked spark plug. Simple, easy, cheap. [/EDIT]

 

[99escladel31]

following just found a worn distributor gear on my 5.7 while trying to figure out no oil to rockers on cylinder 8

 

[Aparke4]

I just replaced my distributor in my 1996 k2500 7.4 vortec and the gear on the "stock" distributor- miles unknown was like a turbo turbine! gears were nearly gone!! I was dreading the distributor replacement for a while as I have a lifted truck and 35's and its a superman/ lay across the engine bay kinda install... well once done I have no backfire issues *was having a slight pop 40 mph and lower decelerating/ not braking after accel* and installed all accel parts: coil, ceramic wires and lastly billet distributor part #59132 + NGK iridium plugs... about 150$ to the door. They claim this part fits all V8's 1996-2000 FYI.

I will see if I can find a pic of the old distributor! Also did valve cover gaskets too while I was back there...body lift creates room but with 35's and a very light crank it can be lotta fun working in the engine bay.