8100 chevy vortec engine swap info


Well-Known Member
Does anyone have a list of the piston options for Vortec 8100s?

I know that Wiesco and Diamond have one and I know Wiseco will cut more valve relief for a higher lift cam.
With the huge bore and stroke and the fuel economy goals of people who tow, I'm SUPER SUPRISED that no one has a nice, thin metric ring pack piston for these engines.

9:1 compression is all you're going to get out of one of these engines (with the stock heads) with a flat top, right?

Anyone know what size injectors they use stock?

-I now a guy looking to rebuild one and get new pistons now and he's super focused on trying to improve the fuel economy during the rebuild.

A really good tune and thin metric ring pack pistons is about all I can think of. Headers often help, but that means losing EGR, so almost a wash.
If he could get some kind of mild bump in compression, I think going with bigger 12 hole injectors and open valve injection would let him still run on 87 octane and give small MPG improvements...



The Grumpy Grease Monkey mechanical engineer.
Staff member
these threads offer a good deal of related info you might need,
reading through them , and related sub linked info contained, will undoubtedly help.

the more detailed info you can provide the piston supplier you select ,
the more likely you are to find the correct match in pistons to the application.

injector size you need will depend on the intended horse power
your piston compression will depend on the fuel octane, heads used, valve train clearance, quench etc.

and most custom piston manufacture's will offer several options on rings, and yeah thinner rings have advantages, but as usual, everything costs more and takes longer to make if your not using off the shelf options.
its critical you get the correct clearances, piston alloys, piston pin designs, free float, pressed etc. heat coatings etc. Id certainly look into a a forged crank, and longer rods with better rod bolts for a racing application.

step one,
decide on the bore and stroke and compression ratio you want,
call several of the suppliers and ask about your options, obviously if your just replacing, original pistons and rings,

you may have to get a set of pistons closely matching the original piston weights,
and you might need a larger bore diameter, and block machine work,

or you'll need to have the rotating assembly rebalanced and maybe clearanced
step two,
you'll generally want to purchase a complete matched rotating assembly (CRANK,RODS,RINGS,BEARINGS, PISTONS ,DAMPER ETC. from a known manufacturer )

SCAT is who I use for most builds, but there are at least half a dozen high quality manufacturer's

there are several aftermarket chevy 8100 cylinder heads

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