New V8 Memcals Available for the '427 PCM

[JeepsAndGuns]

If they cant get it, why even list it on their site...lol

Actually its a AMC 401, not a 454. I just know the 350 knock filters hate it, just curious if the 454 filter gets along with it any better.

[dave w]

If they cant get it, why even list it on their site...lol

Actually its a AMC 401, not a 454. I just know the 350 knock filters hate it, just curious if the 454 filter gets along with it any better.

I'm thinking the knock filter of the '427 PCM for both SBC / BBC are the same part. I think maybe the 4.3 has the same knock filter. I think this because all three types of engines use the same part number for the 4K ohm knock sensor. I'm figuring the main reason for the different Memcal part numbers is mostly for the PROM programming.

dave w

[RobertISaar]

the knock sensors being similar is not a surprise... the 2.8/3.1/3100 60V6 uses the same knock sensor as the 4.6 Northstars....

i would be almost 100% certain that the filter is significantly different between the two applications.

[pmkls1]

the knock sensors being similar is not a surprise... the 2.8/3.1/3100 60V6 uses the same knock sensor as the 4.6 Northstars....

i would be almost 100% certain that the filter is significantly different between the two applications.

Correct me if I am wrong Robert, but as I understand it the actual detonation frequency produced by each engine is relative to the bore size and thus the knock sensors are designed to be "sensitive" to that particular frequency/bore size. The filter is more relative to the engine design/configuration and is there to "filter" out any "noise" from other sources such as valvetrain components etc...

The bore of the 2.8/3.1/3100 was the same at 89mm. The bore of the Northstar is ~93mm. I'm not sure of the bore "range" that a particular knock sensor is effective, but there has to be some kind of range as there are way more different bore sizes in various GM engines vs. the amount of different knock sensors available. Given that my statements are correct, then the AMC 401 would fall right in between the 350 and 454. The 350 has a 4" bore and the 454 a 4.25" bore with the AMC 401 being 4.165. I would definitely want to give a 454 memcal a try. After giving a quick glance at a parts catalog for an earlier TBI truck, the 350 and 454 use the same knock sensor but a different ESC module which definitely piques my curiosities. I am working today so I will run into the parts dept. and attempt to locate a 454 memcal part # that is still available.

[pmkls1]

Ok, so I did a part # cross reference and ran a dealer locator on the two 7.4 memcal part #'s listed in the spreadsheet above. Those part #'s are not superceeded by another number and have been completely removed from the dealer locator system. I also checked in the parts catalog and none of the numbers I found for a '95 C/K truck memcal were available anymore. So, no luck there. There could be a dealer or multiple dealers out there with old stock still on their shelves, but since GM has removed those #'s from their dealer network program you would have to literally call each dealer individually. I do know of a company that buys NOS parts from GM when they become discontinued and they may very well have some of these memcals. I would have to make a call on tuesday to see as I do not know if this company sells to the public or not and the only contact info I have is an 800 number listed in the GM parts catalog.

[1project2many]

The markup on parts from Rare Parts seems astronomical but if you need something, you need it. Partsvoice allows the general public to search subscribers' inventory although the two 7.4 part nos above are not successful. I'd look for memcal and sensor from a medium duty 366 truck engine RPO LS0 which has a 3.95" bore. The modified BCCFind search produces a pile of hits for that engine. For example BCC BSBD part no 16229536 from a non governed closed loop 1997 truck is available from a dealer in Oroville, WA.

HTH

[JeepsAndGuns]

It seems I remember reading that the knock sensors are mostly the same, and its the esc's that diffrent.

I did a google search on the two 454 memcals above, and found this site for one of them.
http://www.gmpartsgiant.com/parts/gm...-16248381.html

I googled the other number and had a hit too, but it was like 160-something dollars.