8.1L/496 BBC Vortech

by BAS-Sr Thu Feb 01, 2018 6:13 pm

Hope someone can help me. I am looking at a 2000 8.1/496 Vortech motor possibly for my '76 Laguna S3. I have done quite a few Gen IV 396/427/454's over the years, just wondering about the differences between those and this newer generation?

It is a local CL ad, supposedly a complete motor with computer, torn down ready for a freshening up.

Anyone know of any good documentation on this newer generation? I have a few of the older books on the Gen IV's.

by 73ss Thu Feb 01, 2018 6:58 pm

Probably best to stay away from it. Very little if anything interchanges with the previous generations. Head bolt location, firing order is different just to name a few. Intakes and heads are totally different. Those engines are a cross breed between an LS style motor and a standard big block. they do look very similar on the outside though.

If you can find a gen 6 454, that would be the one to get. All the main caps are 4-bolts, one piece seals, roller cam. The factory heads are not very desirable. Earlier generation heads will fit with the proper head gasket. I am in the process of helping a friend assemble one. Very nice motors. No fuel pump mount if you plan on running a carb. I will be going with a gen 6 when my current 454 gets tired.

by REVINKEVIN / Mr. 600+HP Fri Feb 02, 2018 12:28 am

Fun reads. I think you will find it more trouble than it's worth. On the other hand, you could pull a camper.

http://www.hotrod.com/articles/gm-vortec-8100-the-454s-forgotten-big-brother/

http://www.raylarengineering.com/vortec-8100-496cid-truck-performance-parts.html

by Iggy Fri Feb 02, 2018 2:44 pm

It is a great engine - in a truck. Very little aftermarket support (read expensive) and limited. The stock computer has torque management programed into it so you can keep the rear tires on the truck. It is actually a metric tall deck so nothing except valve covers or oil pan will interchange, basically an LS Big Block.

One heck of an engine for towing, 10,000# on the hitch feels like nothing, has no power over 4500 RPM but will smoke the tires at will. As mentioned above, go with a Gen VI - still a basic 454 with a better oiling system than a Mark IV, will accept Mark IV heads with a FelPro 1037 head gasket. Also has the provisions for factory roller cam, or can use an old flat tappet. The blocks in demand are the crate engine blocks because they have a fuel pump pad, the ones used in the trucks did not even have the fuel pump pad pored with the block so you have no choice but electric fuel pump.

I am building a Gen VI with the Vortec heads for my 1978 C20 Camper Special, using a 454 HO cam. Vortec heads are good for torque, but are not performance heads, but any aftermarket head and all stock heads will bolt up (you can interchange Gen V and Gen VI head on Gen V and Gen VI blocks, but you cannot put Mark IV heads on a Gen V block).

by BAS-Sr Fri Feb 02, 2018 3:01 pm

Thanks, exactly what I wanted to know!

I'll stick with a 454!

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8.1L/496 BBC Vortech

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