New V8 Memcals Available for the '427 PCM

[dave w]

I used the Moates.net BCC spreadsheet to find the V8 '427 PCM Memcal part numbers. I used the part numbers at an online GM parts supplier. According to the research I've done the 18 Memcals I have a screen shot of are still available from GM. Depending on the GM parts supplier, some of the part numbers were listed as low as $33.50! Who knows, next week GM might make some / all these part numbers obsolete.

dave w

[dave w]

I was thinking about ordering one of these Memcals, but the shipping seemed excessive to me!

dave w

[JeepsAndGuns]

Holy cripes!! Are they serious or you think its a glitch/typo on their part?

I would like to get a 7427 7.4L memcal, I dont care what is on the prom, as long as the esc in it is for a 454. I am really curious to know if it might get along with my engine better than the 5.7L esc I am using now. Just dont want to pay some crazy price for one only to find out its no better.

[dave w]

Holy cripes!! Are they serious or you think its a glitch/typo on their part?

I would like to get a 7427 7.4L memcal, I dont care what is on the prom, as long as the esc in it is for a 454. I am really curious to know if it might get along with my engine better than the 5.7L esc I am using now. Just dont want to pay some crazy price for one only to find out its no better.

Here is the correspondence I had with GM Parts Direct:
My Question ~ Why is there over $410 in shipping charges for part # 16248381?

THAT IS THE TRUE DEFINITION OF INSANE!!!!!!!!!!!!!!!!!!!!! OR STUPIDITY ~ YOU DECIDE??

The Response from GM Parts Direct:
Hi David,

Please accept my sincerest apology for your inconvenience. Part number 16248381 has been discontinued and is no longer available from General Motors.


Thank You,
F Norton

GmPartsDirect.com

On the topic of using a 454 Memcal on a 454, well I think it might be best to go that route. The reason I'm searching for a new Memcal is because I'm troubleshooting what appears to be a faulty Memcal. The Memcal in question is almost always retarding timing, sometimes with the ignition in the "on" position the knock counts go to 255 without the engine running.


dave w

[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

[EagleMark]

I was thinking about ordering one of these Memcals, but the shipping seemed excessive to me!

dave w

Didn't see that coming! Thanks for a great laugh first thing in the AM.

We had started a memcal knock filter number list trying to find differences and similarity's but the thread went stale, I do have and have posted here somewhere that knock sensors are frequency specific for cubic inch, but that may have been with ESC. Now memcal knock filter different numbers are coming into play? Also while doing my sons IH 345 engine with 16197427 PCM system he found different part number for manual to auto tranny. So the knock sensor frequency specific to engine bore size may be a ever changing issue with all the different knock filters in Memcals?

You've been around long enough to know dangers of knock! Little ping won't hurt, but if knock system is not working correctly and you hear knock? Big issue... be careful! Depending on mask ID and the 6000 possibilities of spark advance changes do to bias, what your timing table says and what is happening at timing marks can be 2 different worlds! Take for instance the same $OE bin we both used for starters then roughing in timing table. 5.7L has IIRC 9.84 degree warm bias and 20.04 cold spark bias. 7.4L has 0 degree warm spark bias and 20.04 cold spark bias. POOF! 9.84 degree difference at timing marks when warm just because we used a 7.4L bin and made it a 5.7L bin!

For Jeeps and Guns we are having excellent results with 427 PCM 5.7L memcal using the manual trans knock sensor. Motor is new and tight, using real time advance numbers that should be correct for engine then adding 4 degrees starts to show some retard, adding 6 shows more! So pretty good for a conversion... if you spark table is relatively correct for your engine and your getting knock counts it could be just over sensitive because of engine differences. Over torque will make over sensitive, Teflon tape desensitizes, brass elbow make even more less sensitive.

Slippery slope here using knock sensor as gospel truth in a conversion!

Roughing in spark advance from original motor, making sure timing in bin is actually correct at timing marks when motor is totally warmed up, leaving all other spark bias settings stock is a good starting point, pick an area like 2000 RPM 75-100 map and add 6 degrees so you can half throttle from idle and watch results, test, rinse and repeat...