n00b needs help with the 4.3

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compressorguy

New member
looking for a good source on rebuilding the 4.3 for performance. i just purchased a used 4.3 and want to build it for track use. i admit this is not a ty 4.3, it is out of an early 90's c1500. my initial plans are for an N/A engine but after the car is sorted out and after a few seasons, i may go turbo.
i'm real familiar with the SBC but only vaguely familiar with the 4.3. the one i bought appears to be an even fire, vortec head engine. other than that, i'm really fuzzy on this engine.
what i'd like to know is, can anyone on this forum or another site help me identify exactly what the specs and what year this engine is?
the main reason i picked up this engine is i've heard these engines are very much like a 5.7, minus two cylinders. how much truth is there to that?
how much interchangability is there? it appears that the valvetrain parts are interchangeable, what about rods, pistons, etc?
how much can one of these two bolt blocks handle?
i would like to build it for about 300hp N/A. is that do-able?
 
sean

sean

Member
Re: n00b needs help with the 4.3

compressorguy said:
looking for a good source on rebuilding the 4.3 for performance. i just purchased a used 4.3 and want to build it for track use. i admit this is not a ty 4.3, it is out of an early 90's c1500. my initial plans are for an N/A engine but after the car is sorted out and after a few seasons, i may go turbo.
i'm real familiar with the SBC but only vaguely familiar with the 4.3. the one i bought appears to be an even fire, vortec head engine. other than that, i'm really fuzzy on this engine.
what i'd like to know is, can anyone on this forum or another site help me identify exactly what the specs and what year this engine is?
the main reason i picked up this engine is i've heard these engines are very much like a 5.7, minus two cylinders. how much truth is there to that?
how much interchangability is there? it appears that the valvetrain parts are interchangeable, what about rods, pistons, etc?
how much can one of these two bolt blocks handle?
i would like to build it for about 300hp N/A. is that do-able?
Click to expand...
the true vortec did not come out until the 96 up. go to the vault there is a good right up in there under the holy grail of 4.3 or better yet.
http://www.syty.net/forums/showthread.php?t=20725
 
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compressorguy

New member
Re: n00b needs help with the 4.3

thanks for the link. i already read through it and i'm guessing mine is actually pre '92. i have no balance shaft. i just disassembled it tonight and found it uses the two bolt lifter retainer.
the other thing i found, and likely the (undisclosed) real reason the guy was selling it, is it has a spun rod bearing.
that worries me since this has that odd-looking offset rod journal crank. can these things handle any real power? seems like the joint between the two rods would be a weak spot, especially if the crank ever needs to be turned.
also, holy crap, these heads are heavy! i swear the heads from this thing outweigh my 350 heads. what the hell is that?
as for building this little engine, would vortec heads really make that big a difference, all else being the same?
 
VermontTy

VermontTy

Support Our Troops
Re: n00b needs help with the 4.3

compressorguy said:
worries me since this has that odd-looking offset rod journal crank. can these things handle any real power? seems like the joint between the two rods would be a weak spot...
Click to expand...
stock cranks have been proven to hold 600-700hp properly tuned; no predetonation, etc. Mine did break in half where you're talking though, but it was an engine that was overboosted MANY times, and eventually gave up the fight. Don't let the stock crank worry you; worry about the rods and pistons.
 
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compressorguy

New member
Re: n00b needs help with the 4.3

good to know. speaking of which, are the rods interchangable with 5.7? i have a mismatched set of 5.7 rods that have never been spun i might just as well install.
 
dgoodhue

dgoodhue

BuSTeD 4.3
Re: n00b needs help with the 4.3

compressorguy said:
good to know. speaking of which, are the rods interchangable with 5.7? i have a mismatched set of 5.7 rods that have never been spun i might just as well install.
Click to expand...

No the rods are not easily interchangable. The crank journal is different 2.25 (4.3) vs 2.10 (5.7) and they also need some machining.
 
C

compressorguy

New member
Re: n00b needs help with the 4.3

thanks guys for all the help so far. this is why i love the internet. ain't it great so many car guys are on the net?
so what i've found so far is i believe the engine is a tonowanda engine. the numbers i've found so far are crank casting number 10105865 and heads are 14094768. the link above lists the crank as a tonowanda. i don't believe the engine has ever been rebuilt so i believe the whole thing is original tonowanda.
as stated earlier, it's also a non-balance shaft motor. i can't find much else on the components, there is a number on the front pad but i don't know if it's a part of the VIN or different number. that number is T0604UTJ.
don't know what all this means in the search for more power. hopefully, you guys will give me more news on the do's and don'ts of this engine. BTW, is lightweight as strong as heavyweight? is one better than the other?
 
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