95 4.3 vortec questions.

I currently have a 95 4.3 v6. I'm having the motor redone and i'm having an issue trying to figure out if the bottom end of the motor is different from a true vortec. I've gotten vortec heads and intake but I read the cam is different also. Is this true? I also read the non vortecs where not balanced but my motor is balanced. the builder thinks maybe the block was changed at some point. a picture of the block is below. Any info would be appreciated.

Thanks

Re: 95 4.3 vortec questions.

[Your 95 roller block will need a new manifold that should be it. All the talk of vortec is just marketing...but what GM did do was develop a new head design 96-97 which was a racing head at that time quick cheap power...And ever since then people have decided that was the true vortec motor when in fact it (vortec) was around for a long time. In the link below it give's the chronolgy of the engine changes.

the complete 4.3 history - Car Forums and Automotive Chat
1993-'94 with balance shaft: Things got more confusing with the balance shaft blocks in '93-'94. All of these engines have to have the two extra bolt holes for the strut bosses and 10 bolt holes for the tin front cover. There are five castings that may or may not be right:

* All of the 10224534 and 10224535 blocks have the two strut bosses and 10 holes for the front cover, so they will fit everything in '93 and '94.
* The 10227196 castings have the strut bosses, but they came with either six or 10 holes.
* The 10224834 blocks have 10 bolt holes, but they came with or without the strut bosses.
* The 10235359 blocks were the most confusing because they came with or without the two strut bosses and with either six or 10 holes for the front cover!

Consequently, all of these castings must be checked and sorted by both casting number and features in order to be sure that they will work in everything in '93 and '94.

1995 with balance shaft: 1995 isn't a whole lot better. All of the '95 engines had a balance shaft and the strut bosses, but the flange around the timing gear was changed to accommodate the new plastic front cover. The overall shape stayed the same, but the flange was noticeably wider with big bulges around six of the bolt holes.

There was a mid-year change that can cause problems, too. The early engines used a "first design" tin front cover with 10 bolt holes. The later ones had the "second design" plastic cover that had only six bolts, so the flange can have either six or 10 holes drilled in it. That means that the tin cover won't work on a block that was drilled for a plastic cover, so the blocks aren't always interchangeable.

Things can get confusing in '95, because the 10227196 and 10235359 castings that were used in '95 came with the narrow flange in '94 and were converted to the wide flange in '95. All of the 10227196 castings had the strut bosses, but some of the earlier 10235359 castings didn't.

You can use either one of these blocks in '95 as long as it has the strut bosses and the wide flange with either six or 10 holes drilled for the front cover. But, you must be sure that the corresponding first or second design front cover is installed on the block.

Given the possible confusion over which cover the customer has and which block he really needs, it's probably better to make sure all the blocks have 10 bolt holes so they will work with either front cover. Do not use an earlier block with the narrow flange with a plastic front cover under any circumstances because it will leak oil.

Re: 95 4.3 vortec questions.

So there was difference in cam from a 95 to 96?

Re: 95 4.3 vortec questions.

jay127 said:

So there was difference in cam from a 95 to 96?

Click to expand...

1992-'94 VIN "Z" without balance shaft: The specs for this cam were comparable to the earlier VIN "Z" cams, but the base circle on both the intake and exhaust was reduced to 1.260". The OEM part numbers are 10144176, 10214713 and 10172776.

1993-'95 VIN "Z" with balance shaft: The specs on this cam were similar to the ones used in the VIN "Z" without a balance shaft, but a snout was added for the balancer drive gear. It's a p/n 10144065.

1992-'95 VIN "W" with balance shaft: The premium high output engine came with central fuel injection, a balance shaft and a better cam starting in '92. The original cam, p/n 10144047, was used from '92 to '94. It was replaced by p/n 10241693 in '95. They are comparable grinds so most rebuilders are interchanging them.


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1996-'98 VIN "X" with balance shaft: The VIN "X" engine replaced the VIN "Z" in '96. It is identical to the '96 VIN "W" engine except for a milder cam and 10 less horsepower. The cam is a p/n 10241692.

1996-'98 VIN "W" with balance shaft: The VIN "W" engine has a 10541691 camshaft and makes 10 more horsepower than the VIN "X" engine. There is also a special roller cam for the VIN "Z" turbocharged engines (p/n 10214714) along with a couple more with a fuel pump lobe for marine and industrial applications, but these are the common ones that were used in most of the cars and trucks. All of these cams can be identified by the last three digits of the part number that is stamped on the barrel of the cam, just behind the last lobe and in front of the distributor gear.

Matching the right cam with the right lifter and adjusting the valves correctly is important in order to avoid noisy lifters at startup, a problem that's commonly known as "morning sickness." Prior to '92, the 262 had the traditional adjustable rockers that had been used on all of the small block Chevys for years. The cam had a 1.380"/1.335" base circle and used a short-travel lifter. Turning the rocker nut one turn gave the lifter a .040" preload and put the plunger in the middle of its travel.




Have your mech read that link it will be apparent, actually with vortec heads you probably want a new cam they did improve the engine's abilty to breathe.

Re: 95 4.3 vortec questions.

Thanks for the info. Helped alot