looking to swap my 4.3 v6 for a 350 in my 1990 150.0 silverado. looking for info like if my starter, alternator, ac, and anything else will bolt on. some gearheads say my tranny will be cool might have a problem with my fan being to close to the radiator though. might have to change out ecm and injectors though. yea i know i will have to get a different intake. any feedback from someone who has had experience with this will be greatly appreciated.
I am in the process of rebuilding a sb400 to replace my 4.3. I haven't checked into the starter yet but the altenator bracket and all the rest of the aluminum brackets willl bolt on to the front of a 350 as long as it was made after I think 1969. There should be accessory mounts already in the block and heads. Do you have a standard or auto. This is another piece of info if it is the standard aluminum case gertrag it is a little weak to be putting behind a 350. I have seen it done on one truck and it is on its 5th tranny. For you going with a 350 you won't have too many problems getting the tbi setup. have fun.
I'll just ramble for a little while here: Motor mounts on the frame might be different. Some frames just had another set of holes about 4" further to the front. Some had an extra bracket behind the crossmember for the motor mount to sit on that you will have to remove. Not sure which the 90 is, but I suspect the former. You'll be able to tell if you can use yours once the 6 is out. ECM is the same, you just need the 350 prom for it. The TBI is the same, with different injectors. You make the call on how you want to work that out. Where is the 350 coming from? Does it have any of the emissions stuff you will need on it (MAP sensor, intake, etc.)? Most of the stuff from the 4.3 will be usable on the 350. You can't use the EGR. You will need a different Y pipe. When all is said and done, the engine will be 4 1/8" inches or so further to the front. You will need a new shroud for sure. As for the radiator, some 6's had the same radiator as the V8. Again check the part number. I don't think the 90 model was one of the "good" years for that. Brakes offered on the six were the same as the bottom line of the V8's, so no problem there, unless you are planning on a lot of towing. RWAL needs no attention. Now would be a good time to put a tranny cooler in it, too.
Dont forget the front springs are a little light for the 350. You can get replacements no problem- if it sags too much.
Only if it's 4x4, otherwise it's still a coil...
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