Rod thrown, what now?

[Eargesplitten]

SBC Vortec is easy, only run the long block and slap a different intake on so it'll run off of TBI. Good luck finding a tuner though. That said Vortec 350 motors are a dime a dozen in the pull and pay yards here and if you're trying to be cheap, a bump in fuel pressure may get you by. A tune is the correct answer though.

I meant putting a whole vortec (as in a late small block / big block engine, not LS-based truck engine) engine, harness, and ECM into the truck, someone is selling one he was planning on dropping into a square body. Are the 6th generation big blocks more different than the "big block" name would suggest? I figured if the 454TBI big block was just a matter of plug (and unplug, and plug, and unplug) and play with the transmission and harness and motor mounts the 8100 would be the same and if you're going to put an obsolete giant engine into an old truck why not get the biggest one?

 

[Supercharged111]

When I say Vortec, I'm not talking LS. And the 6th gen is a good motor, it didn't have the stupid morphadite head gasket scenario as the GenV nor did it overheat or in general suck like GenV. The heads were less bad and in general the motor was reverse compatible with MarkIV old school heads. But you can't swing a dead cat around these parts without hitting a decent junkyard 350 Vortec. I live in the Springs, they're everywhere and they last forever. Not trying to discourage you from the big block swap by any means as I have one myself, just trying to make you apprised to your cheaper options.

 

[Erik the Awful]

But I think I saw somewhere they were saying those rods only came on the 4x4.

I thought those rods were a Vortec thing, but I stand corrected. Those were a significant reason why my '99 Suburban K1500's engine swap took twice as long as my '89 C1500.

 

[ralmo94]

The TBi pcm you have should be able to run either engine except for the 8.1, with the right chip. There also is the option to just put a carb and hei on it

 

[Supercharged111]

I thought those rods were a Vortec thing, but I stand corrected. Those were a significant reason why my '99 Suburban K1500's engine swap took twice as long as my '89 C1500.

?? They bolt from the back of the engine mount to the bell housing. I have more faith in you than that.

 

[Pinger]

I don't know the answer.

But I think I saw somewhere they were saying those rods only came on the 4x4. It has to do with the torsional stresses the transfer case exerts on the transmission case because it hangs off to the side.

No transfer case on 2wd, so no reason for them on those trucks.

I think those are what the rods you are talking about?

And, because of the additional torque in (transfer box) low ratio?
(I'm assuming the 4x4s have a low ratio option).

 

[Erik the Awful]

?? They bolt from the back of the engine mount to the bell housing. I have more faith in you than that.

If you've never dealt with them before, they're a pain in the butt. Thanks for the faith, but I'm also pretty good at stepping on my own we!ner

 

[stutaeng]

And, because of the additional torque in (transfer box) low ratio?
(I'm assuming the 4x4s have a low ratio option).

Yes. 4Hi and 4Lo.

The interesting thing is that those rods were eliminated on the later generation trucks. They added those aluminum ribbed bottom flexplate/torque converter cover (and maybe the crossmember was also changed?) on the transmission, at least on the trucks with the 4L80e. Both 2wd and 4x4 have that cover.

On the later 4L60e they had a bell housing that went all around the flexplate, so I think that effectively did the same. The 800 4x4 1500 don't have those rods either.

I really had never seen those rods until I bought my 2000 K3500, but that one does have them. It has the sheet metal flexplate/torque converter cover.

 

[Pinger]

Yes. 4Hi and 4Lo.

The interesting thing is that those rods were eliminated on the later generation trucks. They added those aluminum ribbed bottom flexplate/torque converter cover (and maybe the crossmember was also changed?) on the transmission, at least on the trucks with the 4L80e. Both 2wd and 4x4 have that cover.

On the later 4L60e they had a bell housing that went all around the flexplate, so I think that effectively did the same. The 800 4x4 1500 don't have those rods either.

I really had never seen those rods until I bought my 2000 K3500, but that one does have them. It has the sheet metal flexplate/torque converter cover.

At some point in time, auto manufacturers realised that the bell housing was crucial in reducing NVH as any vibration there is amplified. The rods as I understand them can't add much in the way of torsional rigidity (ie, restraining the torque at the transfer box output) but possibly helps damp the cyclical vibrations. All guess work re GMTs.
My smart's 3 cylinder engine and gearbox was full peripheral - probably to deal with the rocking couple that is inherent in triples and the extra beam strength across the block and gearbox probably benefited from full 360 degree contact.

 

[ralmo94]

I believe my 94 k1500 has them, and 98 k2500 also