Boosted 350 vortec, or stock 8.1?

[letitsnow]

Agree with the LS Turbo. My current setup is a 98 Sub 2500 with a twin turbo LS6 from a Cadillac CTS-V backed by a Hughes built 4L80E. Small turbos and a torque biased cam delivers boosted power starting at 2000 rpm with a very flat torque curve. Has been very reliable and with the aluminum block is so much lighter than the factory big block. Expensive build though. Lots of tuning effort required. Before that I built a turbo charged 454 in a 98 sub 2500. Used a remote mounted turbo from a dodge cummins. That made great power too, was much less expensive and arguably more durable. The turbo solves the sluggish feel of the 454. Any boosted solution will require premium fuel so that is another consideration.

Thanks for the info! Some of the places that I end up with the truck might not have premium fuel. I didn't think that through... I will probably end up with an 8.1 because of that.

 

[letitsnow]

Personally if you're not towing a lot I would stay away from the 81 I have one but I put in my pickup they have a lot of lifter issues mine I put a new cam lifters rocker arms in and I cannot get the valve train to quiet down which jacks with the computer which is giving me trouble. I would go with a vortec and a tuned port system switch over to the 4:11 computer Make sure you got a 4L80 behind that thing and you're going to be knocking on 400 foot pounds of torque and be very nice better fuel mileage than that 81 when you're running empty

Look this over http://www.gmtruckcentral.com/articles/lt1swap.html

That was mine before the 81. When i get the $$$ together, the LT1 will get stroked to 383 and go in my 2001, and 81 will be sold. Yes i kept the motor ;-)

Just my 2 cents

The main purpose of this truck would be to tow our camper. I had never heard of the noise causing timing issue on the 8.1. Thanks for the info.

 

[letitsnow]

2003 was an ideal year for Cummins motor and transmission pairing as far as donors are concerned. I believe it was a 24V, but the only year with a 6 speed and no emissions BS. A basic tune has you at over 700 ft/lb of torque and less rattly than a 12V. Marginally.

Thanks. I have had enough of the 24v experience. I could tolerate the 12v, if not that, than I'd have the 8.1 gasser.

 

[letitsnow]

Why not build a 496 out of a 454?

Or you could go the extreme route and swap in a Duramax? 6.6/ZF6 in and ECSB K2500, anyone else think that rings a bell?

So many options, so little $$$...

 

[L31MaxExpress]

Just going to put this here since headers have been claimed to be high speed only components. An engine builder team actually used Tri-Ys on a winning engine masters build because they found them to add 30 f/lbs down lower in the RPM curve with no loss of peak horsepower.

https://www.google.com/amp/s/www.hotrod.com/articles/get-570-hp-small-block-350-chevy-pump-gas/amp/

I am actually about to put a marine EFI version of the edelbrock performer RPM vortec on my L31 based engine to replace the crossram marine intake as well. Trying to get as much low-midrange torque out of my engine as I can without killing off the top-end horsepower.

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[489burb]

The gmt 800's up here seem to rust so bad that they scare me. They also seem to have a lot of electrical problems. Would rather have a gmt 400 platform.

Thanks for the input though.

Hmmm, my daily is a 2001 yukon, my brothers work truck is a 2007 classic, both zero rust, no electrical problems, they have finicky sensors though, I find them more reliable than the gmt400's, not as tough though. The rust may have to do with the factory that's supplying your area vs mine

 

[Christian Steffen]

Just going to put this here since headers have been claimed to be high speed only components. An engine builder team actually used Tri-Ys on a winning engine masters build because they found them to add 30 f/lbs down lower in the RPM curve with no loss of peak horsepower.

https://www.google.com/amp/s/www.hotrod.com/articles/get-570-hp-small-block-350-chevy-pump-gas/amp/

I am actually about to put a marine EFI version of the edelbrock performer RPM vortec on my L31 based engine to replace the crossram marine intake as well. Trying to get as much low-midrange torque out of my engine as I can without killing off the top-end horsepower.

You must be registered for see images attach

I am curious to see the results of this.

 

[L31MaxExpress]

I am curious to see the results of this.

I am as well sir. I hope it works as well as I believe it will in theory. Theory is sound logic but actual real world results may vary. The dual plane theory is the manifold works as somewhat of a helmholtz resonance chamber and helps boost VE whoch builds torque.

I know in the past I have seen better results with single plane intakes under 2bbl TBI units, trading minimal torque under 2,000 rpm (under the converter stall speed at the time) for massive top-end gains but those TBI units are very limited in flow compared to a 90mm dry throttle body. With adequate airflow I feel the dry port fuel injected dual plane may actually work very well. Looking at the boats tested with this manifold vs the crossram on the same 300 HP Mercruiser 350 it seems the same hull has a quicker acceleration curve with the dual plane. I hope that means the dual plane made more torque but it is only speculation at this point.