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Posted: 3/18/2002 4:33:32 PM EDT
Anybody know what would be involved in putting a 350 engine into a 92 K1500 p/u? It is factory equipped with TBI 4.3L V-6, manual trans, and air. With 228,000 miles, the motor is getting pretty tired, but the rolling chassis is in great shape. I can't afford a new truck, and I need my truck for chores and towing a trailer. I thought about putting a new Goodwrench long block in it, but I could pick up a 350 and rebuild for a lot less while getting a lot more power to boot. The V-6 wasn't doing it with a heavy trailer. Would a 350 bolt up to my clutch and trans? Would the existing TBI work on a 350 with a module change? Or would I have to throw the ubiquitous 600CFM Holly vacuum secondary on it? Would the motor bolt up to the mounts? Thanks
Link Posted: 3/18/2002 4:44:18 PM EDT
[Last Edit: 3/18/2002 5:50:10 PM EDT by hanko]
Thekill, a V8 small block is basically a v-6 with 2 extra cylinders added to the back. You may have to move your radiator foreward due to the longer engine, as the engine/trans joint controls front to back engine location. If so, truck will have duplicate mounting areas for the v-8. You'll probably need a larger (thicker) radiator, and maybe a larger clutch. Bellhousing bolt locations should be the same. I'd go with a complete 350, including the computer and harness. Carb would also work, as long as your state smog allows. You can email me if you need more. What Mickey Mouse said. I'd go very easy on the tranny, and I might start saving some $$ for a v-8 tranny ultimately. Same goes for the rear end. -hanko Edited to add tranny/diff stuff
Link Posted: 3/18/2002 4:49:28 PM EDT
I am not really up on the newer chevys I have a bunch of older ones but as I remember the 4.3V-6 is a 350 missing two cylinders if this is true the 350 should bolt to the trans and the old mounts might even work. Do you have to pass smog? because if not i think you should go carburator just because of how simple they are and the amount of power they can make, but I would put a Q-jet on they get better milage than the holleys and you don't have to tune them as much as holleys in my experience and the Q-jets are also bigger so they will make more power. Things you need too worry about are can the 5speed handle the 350torque and can you old radiator take the extra heat of the V-8.
Link Posted: 3/18/2002 4:51:04 PM EDT
When I started to type no one replied but by the time I was done hanko beat me too it!
Link Posted: 3/18/2002 5:06:06 PM EDT
Very easy switch and a good one too. By all means get the wiring harness and computer - so much better than the carb and WELL worth the effort. Be carefull of the tranny as I do not know if it is same as one for V8 - may be anemic in the torque capacity department.
Link Posted: 3/18/2002 5:10:01 PM EDT
[Last Edit: 3/18/2002 5:13:57 PM EDT by Fred_Short]
The 350 should bolt right into place. The trans flange is the same and the motor mounts should fit. (Now you've made me go look.)No, the new motor mounts will have to be 4.4 inches farther forward. The holes are probably already in the frame. The v6 flywheel will not fit and I wouldn't even think of using the old clutch, too much time and money invested to cheap out now. The TBI from the v6 will bolt on a v8 TBI manifold, performance wise, I don't know. Use an engine ECM for a v8. May use HEI and a carb. Be sure to upgrade the cooling system to v8 specs. The exhaust and front engine hardware should be easy enough to take care of. This sounds like a lot of little details and it is. I know, I put a 427 tall deck truck engine in my 79 ElCamino, it replaced the 305. Fred 1911greg, I know how you feel, by the time I posted, I was #5.
Link Posted: 3/18/2002 8:42:26 PM EDT
Best bet is to buy a complete engine from a junkyard... This way you will have all the nickel & dime parts that will drive you crazy trying to find otherwse... The 4.3 is identical to a 5.7 internally, less 2 cylinders... They share the same bore/stroke combination, same pistons, rods, valvetrain, etc... I'm not sure if the 4.3 is externally balanced or not... If it's internally balanced, the flywheel should work fine... The 350's are all internally balanced, and use a neutral balance flywheel... '86 and newer V8's use a 1-piece rear main seal, and therefore use a different flywheel... Pretty easy to spot... TBI units are larger on the 350, so you'll want to use the right one... Wiring harness should work, as long as you use the ECM for a 350... 4.3 motor mounts should bolt right on a 350, trans will bolt right up too... There is no difference in the length of the motors from the trans to the motor mounts... The difference in length is all up front... You will need a shorter fan shroud, and a thicker radiator with more cooling capacity... If you're just boppin around town, and not towing, the 4.3 radiator will work fine... Automatic trannys make alot of heat, not stick trannys... All the clutch linkage, throttle cable, and anything near the firewall, will be a direct fit... Like I said, they are identical in every way from the motor mounts back... You'll obviously need new exhaust manifolds & Y-pipe... Distributor will need to be for a V8... Radiator hoses you can shorten, air cleaner you can re-use... All the fuel lines will match up fine... Wires & harness to the TBI unit & engine sensors should be the same... Just be sure to change the ECM (Engine Control Module) aka "Computer" Biggest word of advice is to find a complete engine from a wrecked vehicle of the same year... It will be a piece of cake to swap in the 350... GOOD LUCK !!! ART
Link Posted: 3/19/2002 2:32:33 PM EDT
First you get a 5# sledge hammer, otherwise known a SeaBee Engineering Device, BFH, or Chevy Tool....... Seriously though, I'll agree with the others, it should pretty much drop right in without any minor headaches. If it was an older truck without the computer & TBI you could almost do it blindfolded & half asleep. The idea of a v6 in a full size truck just doesn't seem right. A straight 6 definately but a v?
Link Posted: 3/19/2002 2:50:50 PM EDT
4.3L is externally balanced (like the 400).
Link Posted: 3/19/2002 3:43:47 PM EDT
Like I said, they are identical in every way from the motor mounts back... Art, I beg to differ. The front motor mount bolt hole on a 350 block is 17.69 inches from the rear. The total block length of a 4.3 is 17.38 inches with the front motor mount hole 13.29 inches from the rear. I have the Chevrolet Power Catalog on the desk with the dimensions. With a name like Dragracer-Art, I'm sure you may have run into this in the past. If I'm wrong, please accept my apologies. Fred
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