I cant even lie on a 350 I'd second that about 'no computers' it is a lot easier to deal w/ but for some reason the carb'd 4.3 sucks *ss and I never had to 'touch' anything on my 4.3 TBI by just leaving everything close to stock allllllll I did was make a ghetto hood trash air intake run alums and I bought a TBI chip that raised the rev limiters for the shifting and it took off the stock 96mph top speed after that the truck was capable of 136 mph on the speedo although we took into account later the slightly above stock tire size and a friend of mine re-calculated that we got the truck up to like 128mph actual top speed - and that was with the 4 speed auto so imagine if we had another gear!
4.3, 5-Speed swap
- Thread starter RustRocket
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Hey another cool thing about the 4.3 TBI is you can use the old retro digital dash from early 90s lol. Anyway I'm done repping the 4.3. Fond memories of beating my 1st two blazers to death. When they went to the scrapyard the 4.3TBI's in them both still worked the body/frame failed before the 4.3TBI was ever not going to start. Neither of my 4.3 TBI's failed to start on the first turn of the key a SINGLE TIME - except alternators going out. Blazers have same electrical gremlin as other gm of course. Besides alternator I didnt change a single thing but the computer chip and the spark plugs, and the oil. Not a single other mod. 0-60 was definitely under 8 seconds in a box blazer so imagine a cutlass taking off lower to the ground and add an extra gear you get the picture. fast as **** - for the street of course not the track lol
Even if a carb'd 4.3 sucks, anything is better than the crappy 3.8, even with the work put into it, it probably doesn't make even 100hp to the wheel
Did a lot of work with the 4.3 motors and was very impressed with the power that they made. Well they should they are nothing more that a 350 missing 3 and 6 cylinder. Any of the earlier block came with out the mid balance shaft, lots easer to work with. 350 cam and main bearings just not all of them. Rod bearing are different but the timing chain and oil pump are just 350 parts. These are roller cam blocks so check with the cam companies and use one of their cams. On the cheap side the 4.3 marine cam is a good choice for a mild stock application. Heads I would use the 96 and newer vortec with the straight down intake bolts and edelbrock makes 4 barrel intake for the vortec heads. The early trucks 85-86 trucks used a carbed and hei set up. The set up I had was run in a 2800lb S-10 and ran low 13s with very good air. Summer times were mid 50s with the humid air. These motor respond very well to anything you do to a 350 works with the 4.3
While building a V8-killing 4.3 would be great, I'm not going to mess with the cam or anything like that, just try and throw a bone-stock 4.3 in it. Performance is of no concern, I just want a slightly less boring Cutlass
I'm kind of like RustRocket on this one. I prefer the simplicity of a non-computer carbed setup. I've read through some articles on carbureted buildups on these engines, and if you're serious, 300HP or more can be had from a 4.3 in carbed form. As I said before, I don't really want a race car, but I think that a 200HP goal from an engine that displaces 260 cubic inches isn't unrealistic. I guess I'll find out anyway.
I think you guys are missing the point. You can make nearly 250 hp by learning TBI and OBDI and not modify a single thing on the engine but the throttle cable and you could get someone at the junkyard to basically throw the TBI setup at you for less than $200 and do all this in less than 3 days of finagling w/ wires it all plugs right in and the upstream 02 sensor doesn't even have to be in the cat for it to run I chopped mine off and gained even more power w/o ... just blows a little extra smoke and thats it! I didn't even use a cam on my 4.3. Would hate to see the bills you guys are about to run up at the machine shop instead of just buying a bunch of junk worthless TBI stuff that would have ended up in the crusher at the junkyard... Working heads, installing cams, waste waste waste. Can get to 250 w/ nothing but the computer and I'm sure of it... would cost like $250 instead of $2,500... Any motor is going to be the ****ing sh*t if you spend 2 stacks on it - my point was that the 4.3 is already the ****ing sh*t and people just don't know about it or they would save the tbi from an old blazer and set it up w/ the vortec heads easily... which flow plenty fine stock and don't need worked over by the way I had the vortec heads w/ TBI and it worked perfectly
pencero said:
I'm sorry, but i think that it would be HIGHLY unlikely that you can "make nearly 250 hp by learning TBI and OBD1 and not modify a single thing on the engine" on an engine that made 160-165 hp from the factory. You're not going to pick up 85-90 hp with just a tune on a TBI 4.3.
If your starting with a motor that had the TBI heads your at a loss to start with. With intake ramps being the biggest problem. Those head keel over at around 4200rpm. Get a good set of vortecs bolt them on and a upgrade cam and your easily their. All motors are just air pumps. The more in the more you get out. Those early TBI heads were good for just going from point A to point B with good low end power.
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