Curiosity Killed The Cat

[1972RedNeck]

Ever since I discovered the 8.1 Vortec, I have wondered what the differences are between it and a 454 Vortec. I know the stroke is different. Will these bolt in place of a normal 454? Is there a carburated intake manifold that fits them? Will standard BBC heads fit them? In the future I might like to put one in my $100 4X4 beater.

[prostreetC-10]

......and here I thought my left front tire killed the cat!

[IGOR]

See below

[IGOR]

Originally Posted by 1972RedNeck

Ever since I discovered the 8.1 Vortec, I have wondered what the differences are between it and a 454 Vortec. I know the stroke is different. Will these bolt in place of a normal 454? Is there a carburated intake manifold that fits them? Will standard BBC heads fit them? In the future I might like to put one in my $100 4X4 beater.

7.4 liter vs. 8.1 liter

Yes, they will bolt in place of a normal 454.

Dart came out with carb intake last April: http://www.dartheads.com/products/in...-manifold.html

Standard BBC heads will not fit.

Lots of info in this link:http://coloradok5.com/forums/showthread.php?t=283625

[1972RedNeck]

Did they use a distributor? What would it take to run a normal HEI?

[IGOR]

No distributor - computer fires coils at proper time.

8.1 is LS based top half (intake, fuel injection, electronic coils on valve covers), and similar to 454 on bottom half - (but has different firing order, different crank, etc)

I don't know what it would take to run normal HEI - likely have to figure out if there is worm drive gear on camshaft (which I'm not sure) and work that out with firing order sequence.

But - why not keep the electronics? You would be getting rid of one of the key best features of that motor. You can get modified plug & play harnesses most anywhere, and they are cheap - four wire hookup. I've seen them as cheap as $250 up to $900.

You can use 8.1 computer to control 4L80e transmission, which is the younger brother to a T400 but with overdrive gear. Or get an Allison and get a big duty transmission with 5 speed & overdrive.

[1972RedNeck]

The dart intake says it has a hole for the dizzy. The cam might be a problem though.

As for the electronics, I like what I understand. They're probably pretty simple,but there's not much to go wrong with HEI and a carb(except the module of course).

[GASoline71]

The 8.1's are still pretty popular with the offshore boat racing cats. I would search through some of the websites that pertain to offshore boat racing.

The 8.1 is a kinda bastardized engine and never rally gained much popularity. Hence there is a very limited aftermarket for them.

Gary