Hi guys
I will be installing a Comp Cam 260 stick into my 4.3. I want to know if I need to upgrade my lifter retainer in order to allow the increased lift or if the OEM part is OK. The lobe lift is .35" versus .25" stock.

 

If you are getting new Comp lifters, I would think the crossbars will come with them. Or you may need to order them separately. I wouldn't re-use the stock lifters on a new cam. New cam means new lifters too. That is why they sell kits, so you get new lifters, matching springs for the cam, etc. To do it right, a kit is the way to go.

 

Believe me, I know quite a bit about building motors. I assembled and turned every nut and bolt on this motor. Been building motors for 30 years, everything from stock rebuilds to 6-800 hp motors without any power adders like NOS or Turbo's. I'm pushing about 575hp with this 389" (4.060 bore x 3.75" stroke) on 5.7" rods and full floating forged pistons.

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BlazedByU

Any recommendations about the 4.3 V6?
I have to live with this engine and am planning to do a complete rebuild and tune up on a 100 k miles engine that sits in my garage.
I have access to a machine shop (very, very competent) and will do most of the work myself.

The outcome should be:
Use the stock TBI, headers and exhaust with catalytic converter.
Keep it street legal - cat will help as the 1994 is O2 sensor

Some 220 hp at the crank so I have about 200 hp at the flywheel when it sits in the car.
As flat a torque graph as possible with peak hp at around 3'500 rpm.

Have you ever built something like this with the 4.3 V6?
Would be nice to hear what can be done.

Mark

 

Sounds like you simply want a stock early 2000's MPFI Vortec V6. Your TBI and your heads are the weak links to making power. Unfortunately this later engine is not compatible with your vehicle electronics. You could probably do one with aftermarket fuel injection or a carburetor, but to do one emissions legal with all the later electronics would be tough.

 

I was afraid that it would come to that.
We'll see what happens during the rebuild. I may fit an EFI on it. As long as it looks stock and passes emissions it will be fine.

 

Information about the lifters.

I have disassembled my 1994 4.3 V6 with TBI and balance shaft two days ago.
The lifters are held in place by a plastic bar along the sides of the lifter valley.

During the week I will take that one apart as well as I have to remove the balance and camshaft. I'll measure what additional lift would be available before they bend.
Another thing with higher lift is the oiling gallery which supplies pressure oil to the hydraulic lifters and if it is not lifting the roller lifter too high out of the bore.

If I can come up with some figures I'll let you know.

Chevyabuser369 I would simply call Compcams with your VIN and engine codes and talk to them. They should be able to point you to the right material.

I've been looking at that cam too but still unsure about what will happen to the rocker part not yet decided on the camshaft. It will be a mild cam for sure but will need new lifters (I fancy the paired ones with the horizontal link) and eventually a shaft rocker system if I can fit it properly. Looking at steel rockers but have to figure if the Magnum Pro rockers price tag of 380$ is for the piece or the set of 8.