Alright i have a 99 bravada with 218k (actually my girlfriends) anyways i am wondering which 4.3 motors will work for this year. these s series blazers are very new to me. i come from a world of hondas lol. And with them its all about obd0,1,and 2. if you put in a older engine in a newer car say obd0 in a car with obd2 setup. well its going to take alot of wiring and plus i think it is not legal to have an older engine than the car. vs. only having to do minor thinks like jumper harness. i could swap over an Obd1 b18c1 which is a dohc vtec motor out of an integra gsr, into an integra ls (non vtec. Came with
b18a stock) with obd1 setup as well. so ik certain years or generations have the same type wiring. untill they change again. So im guessing a 95-97 4.3 will one b illegal to swap into my 99 and 2 be a headache of wiring. anywho i have an opprotunity to get my hands on a 01 or o2 4.3 vortec.. one came out of an s10 truck with 65000 and one came out of a jimmy with 75000. would these motors work fine as a drop in swap or are there tiny adjustments that will need to be made. the motor that came out of the jimmy was in fact a 99 sorry my mistake, but it is currently in an 02 blazer and the kid could not get it to run (his mechanic anyways) bc ig he needed a whole new harness. would the 99 motor be the best way to go? or will the 01 work just as well?

 

I really doesn't know about USA law (but here in Chile is a pain in the a.. change the same motor model and practically impossible to get legal papers if install different model motor).

Happly, Vortec 4.3 series between 1996 and 1999 doesn't have to many differences. Mainly is fuel "inyection spider", fuel pump, distribuitor cap and some thing more. So you may swap engines, changing little hardware (for instante, you could take the hardware from actual engine and put on the "new one"). Of couse, it could be a good choice the put a new engine and trany.

As you say, installing a totally different engine will have a big headache trying to reconnect sensores between engine and the correspondant ECU (so you need engine with trany, wirings and ECU). Also, if you new engine have a different fuel supply system, could have to adapt a different fuel pump (blazer fuel pump have a return line to tank without backpressure valve because it seams to be added to the fuel regulator assembly.. other makers put this valve in fuel pump assembly. Also fuel pressure in blazer is higher than other (4 bar, other engines could have 3 bar). Overpressure could damage the engine...

But, some issues goes for:Why change engine? low cilinder pressure? bad engine block condition? Heavy corrosion?. In some cases, an engine rebuild could be a better choice (ask for quotation first, of course).

And, according to millage, a trany service/rebuild could be a good choice if not changed, since putting too much money in engine could need a trany service in some time on (as far as I know, trany dies before vortec...)

 

I believe the tranny has been changed at 150k~. i think i will check compression first before making a decision to get a new motor.