383 balancing puzzle

[Mbosse]

Okay so this forum has been my lifeblood for this project so far and once again I’m back with questions. Real quick I have a 99. I bought a 383 on a gen 1 block with two peice rear main seal. It has vortec heads and was carbureted. I’m putting my vortec intake on it. So for a crank position sensor I am putting a vortec timing cover on which lines up. I think I’ll have to shim the gear that sensor reads but it should work fine. Now it’s an externally balanced crank and came with a balanced that had the offset weight. The problem is it’s a smaller one that won’t fit over the bigger timing cover. So I’m looking at vortec balancers for a 383. They would work fine but say they are only right for a one piece rear main flywheel. which obviously won’t fit on my gen 1 block. So is it going to not be balanced with a newer balancer and the old style flywheel? And if so how can I fix this problem. Should I try a different method for a crank position sensor or can I maybe find a balancer that would fit that bigger timing cover with the wheel. And will the old style flywheels match up to a 4l80? Any help would be appreciated

 

[Schurkey]

I bought a 383 on a gen 1 block with two peice rear main seal. It has vortec heads and was carbureted. I’m putting my vortec intake on it. So for a crank position sensor I am putting a vortec timing cover on which lines up.

Probably have to yank the two dowel pins out of the front face of the block to get the timing cover to fit.

I think I’ll have to shim the gear that sensor reads but it should work fine.

No promises on what timing chain was used on that engine. If it's a double-row chain, the reluctor for the sensor probably won't fit under the Vortec timing cover. You'll need a single-row chain and sprocket set. The Vortec single-row set probably won't fit the camshaft unless it's a step-nose core, and that's really unlikely on a two-piece-rear-main block.

Now it’s an externally balanced crank and came with a balanced that had the offset weight. The problem is it’s a smaller one that won’t fit over the bigger timing cover.

Probably a typical "400" torsional damper (which likely means a typical "400" flexplate as well.) I don't know why it's "smaller" and why a "smaller" damper won't fit "over the bigger timing cover" because a damper does not go "over" the timing cover, it goes in front of, and through the timing cover. Doesn't make any sense to me.

So I’m looking at vortec balancers for a 383. They would work fine but say they are only right for a one piece rear main flywheel. which obviously won’t fit on my gen 1 block. So is it going to not be balanced with a newer balancer and the old style flywheel?

I bet a "Vortec" torsional damper is neutral balanced, so NO that's not going to work well. The damper does not fit the "block", it fits the crank and timing cover; and from a certain perspective it fits the timing set plus the reluctor for the crank position sensor--which means you're going to need a shorter damper hub to maintain pulley alignment.

And if so how can I fix this problem.

I don't know. You're gonna need an external-balance damper with a short hub to suit the CPS reluctor, AND the timing mark positioned to align with the timing indicator on the Vortec timing cover. Start looking through Summit/Jegs and see what you can find.

OR

Disassemble the short-block so that it can be internally-balanced in front like the Vortec engines. If you go that route, you may/may not want to mess with the balance at the rear as well, so you can use a neutral-balance flywheel/flexplate. Your call at the rear.

Should I try a different method for a crank position sensor

No.

or can I maybe find a balancer that would fit that bigger timing cover with the wheel.

I don't understand why the damper has to fit the timing cover, aside from the convenience of having the damper diameter suitable for the timing indicator on the cover.

And will the old style flywheels match up to a 4l80?

I don't know. Kinda thinking that three holes will line up out of the six converter bolt holes in the torque converter. I don't know that for sure.

 

[Mbosse]

The vortec timing cover extrudes in the front a bit to fit the sensor. The old damper has a weight in it that sticks towards the engine further than the damper itself. A vortec damper is made for that extrusion and extra length out. I shimmed the cam position trigger wheel or whatever and it sticks off the block the same as the old engine I think it will work. I may be able to find an 8 inch for the gen 1 that would fit around that extrusion just by chance but it also might not be the same lengths and such for it all to line up wherase I’m almost sure that vortec damper with my shimmed trigger is so far proportionally right. Biggest issue is the balancing difference if I use a new harmonic balancer and an old flywheel