Thinking of changing to 16197427

**dr5375** · 07-18-2014

Hi All, I have a 1987 s15 with a 305/700r4. The engine is essentially a vortec 305 with a corvette lt1 cam and a GM TBI vortec intake. Currently it has a 1227747 tuned by EagleMark (THANKS Mark!) and it runs very good, but being an old hotrodder I am always looking for improvement. I have been reading on here and it looks like changing to the 16197427 might be the next logical step. Would it be enough of an improvement to warrant the change and have someone to tune it for me? Would it help with driveability, mileage, etc?

**EagleMark** · 07-18-2014

It's a much better PCM but the only way I would do it was if I needed control for an E trans!

Or really bored and wanted more options to tune...

**Fast355** · 07-18-2014

Originally Posted by EagleMark

It's a much better PCM but the only way I would do it was if I needed control for an E trans!

Or really bored and wanted more options to tune...

While I value Marks opinon since he is tuning your truck, if you can source the parts and have the mechanical/electrical knowledge to swap I would have done the swap YESTERDAY!!! The 7427 is worlds above the 7747 in driveability.

I have rewired more than one vehicle with a 700r4 to use a 4L60E.

**JeepsAndGuns** · 07-19-2014

I love my 7427 swap. From day 1 it was loads better than my old 7747. Even when I first plugged it in and had done no tuning, I already noticed it running better, smoother, and almost felt like it had more getup and go. The faster datalogging is woth it alone to me.
There is a slightly steeper learing curve to tune it, but in my opinion, its worth it.

**dr5375** · 07-20-2014

I went to the junk yard today and the only 7427s I found were BJYL, BJLH and BNKM all for a 5.7 I think. Did not find any 5.0 PCM at all. Now from what I have read on this forum and TGO (thanks Fast355 and EagleMark) I think I can handle the repin, etc. But, since I can not tune that is as far as I can go without help. One thing I am still unclear on is the VSS. Being a 87 (cable speedo), I think the signal to the computer comes from the speedometer in the dash not from the tranny. Will this work or is something else needed?