Another 4.3LX Vortec Upgrade

[jgrant911]

So I'm doing going to be doing some work on my 180hp 1995 4.3LX Alpha drive this winter and though I would do the intake/head update while I'm at it. The drive number is 0F605187 and is a non-Vortec with the Weber 4bbl and Thunderbolt IV and a Closed Cooling system. I have been told, and have confirmed myself that this number is listed as a 1996 Vortec model in the database but I have verified it is the 12 bolt intake so definitely not the updated heads.

I plan to source clean 2000+ heads (with the roller rockers) from a parts yard and pick up a new or used marine manifold (part number 824330T1). These are to only parts I plan to change other than seals/gaskets etc. I will re-use the original Carb. I have read every thread on all the websites I could find and these look like the recommended parts for what should be a straightforward re-n-re job on the intake/heads.

My question for the pros is, am I missing anything? Based on what I've read, the configuration I will end up with is exactly what the 205hp, 1996+ units look like.

Things I'm not sure of are:
- read some comments about a different way of doing final assembly on the heads with the roller rockers?
- are the pushrods the same (can I keep my originals)?
- use standard gaskets with closed cooling engine?

Comments?

Jim G.

 

[FreeBeeTony]

So I'm doing going to be doing some work on my 180hp 1995 4.3LX Alpha drive this winter

How can you talk about winter............it took long enough for summer to get here!!!.......

 

[jgrant911]

I know, way too early, but I have to start thinking about it now or by the time I figure out how to do it, and actually get it done, it will be too late for next summer!

 

[FreeBeeTony]

I understand.......just could not pass up the comment.............

 

[jgrant911]

OK so I was really hoping I would get a thumbs up from one of the engine experts on the forum (bondo, AllDodge, etc...) on at least my question about the 2000+ 4.3L roller rocker heads on a 1995 4.3L block.

Drop-in replacement for the originals or no?

Thanks!

Jim

 

[Bondo]

read some comments about a different way of doing final assembly on the heads with the roller rockers?
- are the pushrods the same (can I keep my originals)?
- use standard gaskets with closed cooling engine?

Ayuh,.... There's changes in the hardware used on the valve train, that I'm not up on, 'n call my Machinist if the need,....
That includes the choice of push-rods,...

Heads wise, '96, 'n Up is Good,....

I use Fel-pro gaskets, the price for the SSteel fire-ring, over steel, is minimal,...

Closed coolin', ya could do Aluminum Vortecs, if ya can find 'em, 'n are willin' to pay the price,.....

 

[achris]

Nope, pushrods ARE different. Pre-vortec - 17339, vortec -173391....

Chris.....

 

[jgrant911]

Thanks Bondo, I'll check further on the pushrod question before I start the project. Will be sticking with cast iron heads; trying to keep this within budget!

Jim

 

[Bondo]

Thanks Bondo, I'll check further on the pushrod question before I start the project. Will be sticking with cast iron heads; trying to keep this within budget!

Jim

Ayuh,... It's still an honest 20hp,....

If you were rebuildin' the motor, I'd suggest matchin' pistons, for abit more oomph,.....

 

[Volphin]

There are a few options to consider. If you find some Vortec heads with factory roller tips, use them with the new pushrods. If those are hard to come by, use a regular Vortec head and have the studs changed to 3/8 (will have to be tapped and threaded by your machine shop… the originals are press fit) and run comp cams roller tips. In this case, the pushrod geometry works fine, just get new ones from comp, or go with hardened. Another note, the pushrod/oil drain holes need to be opened up to 1/2" by the machine shop as well. I'd ditch that intake and go with an Edelbrock 2114.

 

[jgrant911]

Thanks achris, I had noticed the difference in the pushrod part number while doing more research. So far I plan to use the 173391.

Volphin and others, my understanding is the 4.3L engines (at least the truck version that I will be getting my parts from) went to rail mounted trunnion bearing rockers from 2000 on. I don't think the stock motors from that era ever had roller tip rockers (I am willing to be corrected on that!).

I am trying to confirm if Vortec heads from a 2000 model year Chevy/GM 4.3L TBI engine along with the 173391 pushrods from that same engine, will be a drop-in fit to the 1995 non-Vortec motor in my boat (with a new 8-bolt intake manifold, of course).

Anyone have any direct experience with this swap?

Thanks!

Jim

 

[Volphin]

The 4.3's after 2001 have a roller trunnion rocker with the standard slide tip. The only GM engine to have ever gotten OEM roller tipped AND trunnion rocker arms was the Gen II KT4 from the 1996 Vette. I went to aftermarket 1.7 roller tips rather than the trunnion. I would have gone Crane gold RRs, but I ran into valve cover clearance issues.

 

[jgrant911]

Thanks Volphin, that's what I thought. I'm only looking for "updated stock" performance here so I just plan on changing my non-Vortec heads to the 2000+ Vortec version with the roller trunnion rockers along with the matching pushrods and 8 bolt intake, keeping my stock 4BBL Weber carb.

 

[Sherminator]

I am not 100% about a V6, however i did put a different intake manifold on my 98 5.0 mercruiser, I thought for sure it had vortec style heads. Well ordered the Vortec style manifold and it turned out that mine was NOT vortec style..
So my thought to you: take a look at the intake manifold. You may need a different one if your old heads were non vortec and the new heads your installing are vortec. JMO
good luck!

 

[Tail_Gunner]

4.3L Rocker Swapping 101

There ya go