Every Now And Then I Here Of A Dispacement Of 496, How Do They Come Out With That?
I Just Got Hold Of A 2001 0r 2002 Tahoe With A 8.1 Or 496, Will That Engine Bolt In The Engine Compartment Of A 70 Chevelle?
Kinda Cool To Have An Efi Chevelle.
Thanks

The aftermarket 496's are based on a 427/454 case bored .060" over with a 1/4" longer stroke than a 454. (4.250")

A 496 is a 454 bored .060 over (4.310") and stroked to 4.25" The 8.1 is based on the gen VI 454 vortec engine. It has a stock 454 (4.250) bore and a 4.37 stroke. They are a low RPM truck tuned engine built for economy and low end torque that makes 340HP @ 4200 rpm and 455 ft./lbs. @ 3200 rpm.

Hey Scott, is the generation V1 454 totally different than the old LS5 or LS6 meaning engine mounting brackets, transmision mounting holes for and older style trans? do they even offer after market parts for this engine.
engine any good???

thanks I appreciate your help...

Jakeshoe has had an 8.1.

Might ask Jake over at MadMike's NastyZ28 site, Second Generation Camaro Owners Group.

pdq67

The 8.1 is a grunt motor for trucks and is a gas hog! You can do so much better for your Chevelle than that.

The 8.1 is a grunt motor for trucks and is a gas hog! You can do so much better for your Chevelle than that.
I remember when they claimed the same thing for the 454. Only the 427 was a "real" Corvette engine...

The 8.1 was built in a marine version, decent HP and torque. GM even contemplated making a performance crate engine out of it--it was listed as "coming soon" in the GMPP catalog a few years ago.

Only one company makes replacement aluminum heads and a more-traditional EFI manifold for it; and they're expensive.

Don't forget you'll either need an aftermarket computer; or you'll have to install an electronic gas pedal--the 8.1 is drive-by-wire.

ALL the bolt holes are metric--don't shove 3/8 bolts into the bellhousing to hold it to your engine stand. Same with the exhaust manifold bolts and the motor mounts. Even the back of the crank is metric where the flywheel bolts on.

Oh, yeah. The 8.1 is a Gen VII, not Gen VI. Totally different block--it's a "tall deck" engine; and the oil pan rails are wider so earlier pans won't fit. Earlier heads will NOT bolt on, three head bolts have been moved over ~1/4 inch or so--including the two that have the dowel rings. GM did make a "show vehicle" where they installed the earlier heads on the 8.1 block--but--I bet they grabbed a block off the assembly line BEFORE it was drilled for the head bolt holes, and then drilled the deck to the "old" pattern.

I have to say that if I was to mess w/ an 8.1, I would plug the decks and redrill them so I could install a Mark IV topend and then go!

Jake told me that it's too much trouble to try to use the 4.37" crank in a Mark IV block so I stopped!

pdq67