bbc in med duty trucks ?
 

so over on another board we got a question going . did they ever do 454 std or tall deck factory in c40-up trucks ?

i have always read its a nope and now this flyer popped up from one of the guys showing a gas v-8 7.4L engine .

for square body and older stuff only .

Re: bbc in med duty trucks ?
 

Got a 99 gmc c5500 with a 454

Re: bbc in med duty trucks ?
 

To my knowledge there was never a 454 tall deck. Only 366 and 427s

Re: bbc in med duty trucks ?
 

to new . sorry should have said square body or older only .

Re: bbc in med duty trucks ?
 

I think on mortec.com they did list a tall deck 454. If you think there isn't much difference, and of course blocks are the same.

Re: bbc in med duty trucks ?
 

10134366...454T..............4-bolt, Bowtie, Gen.V, Tall deck

14044807...454T..............4-bolt, Bowtie, MkIV, CNC prep, Tall deck, 4.25" bore or 4.495" bores


don't think last one counts lol. and first one is late 90s?

Re: bbc in med duty trucks ?
 

I stand corrected and learned something new. Thanks

Re: bbc in med duty trucks ?
 

For a few years, starting in 1979, GM did offer a 454 in the C-65/6500 series. Not sure if it was a tall deck or not. There were later Mark V/VI tall deck 7.4L's, and the 8.1L's were all tall deck.

Re: bbc in med duty trucks ?
 

You ask about BBC but then it seems you are only talking about the 454. There were certainly BBCs in medium duties ever since there have been BBCs. I don't know what years, if not all years, but there certainly were 454s put in medium duty squarebodies. So the argument is about 454, right? Because we all know the 366 was a medium duty-only BBC

Re: bbc in med duty trucks ?
 

The L21(98-00 medium duty specific)454/7.4 was a standard deck engine(also Gen VI). All of the L18(01+)496/8.1 engines were tall deck.

Re: bbc in med duty trucks ?
 

That makes sense because I think the medium duty L21 used the same intake manifold as the light duty L19 7.4L.

Re: bbc in med duty trucks ?
 

It would be the same intake as the L29. The L19 was TBI.

Re: bbc in med duty trucks ?
 

You are right, typo!

BTW- didn't the L21 have distributor-less ignition?

Re: bbc in med duty trucks ?
 

Yes. It had a big camshaft position sensor where the distributor would be. It had a drive by wire throttle body, and each cylinder had its own ignition coil.

Re: bbc in med duty trucks ?
 

Do these newer 01+ tall deck engines come with timing gears or timing chains? The old 366 and 427 tall decks had timing gears.

Re: bbc in med duty trucks ?
 

Yes. They have chains.

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