engine/transmission modifications
 

Alright, I have a 95 Jimmy 4x4 with the 4.3 Vortec and lame 4L60E tranny (with OBD II). I put 4"s of lift on it with 31x10.5s. Now I need performance mods. As far as the intake and exhaust, I am going to do a 2.5" exhaust from the Y-pipe back with a dual outlet. With this, should I do new headers and Y-pipe along with it? Along with a CAI. I am also thinking about putting the MV3500 (right?) manual 5 speed in it, what kind of benefits will this give me and what will I need to do as making mounting and such for the parts? Now for the PCM... I heard about the "PCM for less" and would like to know what mod i should get for better mpg and power if possible.

Another thought I had was that some of the later full size trucks had the same setup with the 4.3 and 4L60E and wondering if just switching the PCM to on from a full size would do anything if it is programmed different, since it is a full size and needs more power?

the cai is almost worthless needless to say, but the pcm i dont know if it would do much to anything, but the exhaust is a good idea

CAI is almost pointless performance wise. stock air boxes breath just fine. your exhaust is a great idea and one of the best. performance wise for cheap. if you want to do anything for your pcm/ecm get it reflashed don't swap ecus like that. it will cause more problems than anything.best performance options

exhaust
head work
engine overhaul
forced induction
and
nos

not in that order

Best performance mods for a 4.3 is the wynjammer supercharger. The company that makes the supercharger sells enough mods to DOUBLE the stock horse power. Headers can be very expensive and aren't really worth the small amount of power they add. You can do the same thing by running 2.5" pipes from EACH header straight back (TRUE DUAL EXHAUST) that way they aren't both being forced into one small pipe. You can also port and polish you cylinder heads and the intake manifold that will allow for MUCH better flow. Also a little trick I found to make that little v6 sound like a bad ass V8 is by adding a cam-shaft with a higher duration -
I think it sounds pretty awesome and people DO NOT expect that sound coming from a V6.
Wynjammer site - GM S10 4.3 Supercharger ,GM 1500 4.3 Supercharger , GM Supercharger,S10 Supercharger,
Overall the CHEAPEST way to get the MOST horsepower is to do an engine swap I have seen people swap in ls engines, 5.3L sbc, 5.7L sbc, LT1 From Mid 1990's Z28 Camaro's. You can upgrade the 4L60E Wynjammer website has a couple of things listed for that, or you can swap in a 4X4 700R4 tranny which has more upgrade options and also is made in manual and automatic.