Lets talk different 454's over the years...

[rjfguitar]

I've got three 454 trucks now, a '76, an '81, and a '98. I'd like to know the horsepower/torque of each engine, generation, and what is different between the three.

The reason I am asking is because my '81 has a lot more pep than my '76. The Vortec 454 is obvious on the changes, and am really only looking for the power numbers on that engine.

'76

'81

'98

My main thing is wanting to know what was changed on my '81 454 from the '76, as it is so much peppier and both have identical Th400's and 4.10's.

 

[4X4HIGH]

Between the 2 ealier engines there were many different heads that could have been used. Some heads flow much better than others. There are 2 basic intake ports for passenger/truck heads and one is more destined for HP and the other for torque. Cams have changed over the years as well but the years in question should use the same cams. There were several different pistons available as well. Unless you are positive that these are the original engines there is no way to know what the differences are without pulling the engines apart to check for the same pistons and cams. The heads however you could pull a valve cover and check casting numbers against each other to see if the heads are the same.

 

[rjfguitar]

The '81 has the original engine, the '76 is on it's third engine. So yeah, going by original on the '76 won't work. But, I do know that when it was rebuilt for the third time the same heads were used, just machined and rebuilt.

So I am guessing you are refering to oval port and rectangular port heads and intakes? What would be your best guess the original 454 has in my '81? What should have been put in the '76 originally?

 

[4X4HIGH]

Nope, i'm talking about large oval port and the small or peanut port heads. The rectangal port heads were only used on cars of the Hi performance vintage back int the late 60's early 70's. GM is now using the rectangal port heads once again on some of the crate Gen V and Gen VI BBC's

 

[rjfguitar]

Oh, ok. I thought peanut port heads were more of a 90's thing?? Apperantely not?

 

[Tominator II]

Did brand new valvesprings get put on the 76 when the heads were rebuilt? That can make a big difference.

 

[rjfguitar]

I honestly don't remember, I helped in the rebuild, but I was just a kid at the time.


Does anybody know the power numbers on these factory engines?

 

[BadBob]

1976: 240hp at 3800 (net) and 370lbft at 2800. They list the compression at 8.15 to one, but I swear I've seen them actually checked out at about 7.5:1.

1981: 210hp at 3800 and 340lbft at 2800. Compression is listed at 7.9 to one.

Now, that's what GM says about them, in reality, who knows.

Mine seem to be the opposite of yours. My 77 burb has a whole lot more power then my 85 pickup does.

 

[b454rat]

I've had a bunch of different 454s, and of course they all run different. My 97 was OK, but moving 6500# takes alot anways. My old man has pretty much the same truck, but lifted with 35s and still with 3.73s. Of course it's kinda doggy. My 89 with the 40s and 3.73s still has more power than the old man's, maybe even my 97. The motor was replaced in the 89, never ran the #s, so have no clue what it is. Never even had the v/c off, never needed to, it runs like a top. I think it's an 80s or maybe late 70s motor, thre is some blue paint here and there. Anyways, dunno what the horse and torque numbers of different year BBCs, but like 4x4 said, heads play a big part in it. The peanut ports are good for low end torque whereas the oval are little higher up in the RPM range. Still a torque head though. Soft cam is common is these motors too, specially the late 70s/early 80s. 454 that was in my old 84 was from an 81/82 dually and had a toasted cam, which toasted the heads. Would roast the 35s after I got done with it....

 

[diesel4me]

had many,all were not equal!..

I had at least 4 vehicles with 454's in them....

One was a '74 C10,came factory with the 454/TH400,had 3.08 gears..it went good,but what 1/2 ton truck with a BBC doesn't?..it was rated at 235 HP,and 360 ft lbs of torque..seemed a bit tame to me though,for having a 454..

I had a '74 Monte Carlo with a factory 454 also--bought it for parts with no title,so it was never driven,other than the ride home from where I got it one dark night!.. --I did try out the 4 barrels a few times,and I had no trouble roasting the tires for over 300 ft with it!..had a TH400 too,which still sits in my shed 15 years later!..

This 454 had non foulers on some of the spark plugs,smoked a bit,but ran much stronger than the one in my '74 C10 did..looking up engine codes revealed it was the 290 HP,360 ft lb version..not sure what gears the car had,most likely 3.08's..I traded this motor for a "fresher" 454 from a 1973 Impala my brother parted out--.

I put that '73 Impala 454 in my '72 Chevelle wagon ,that sat on a '69 Suburban chassis..it was by far the strongest runner of them all,it had a fresh valve job and a Holley spread bore carb,but was otherwise bone stock,even had POINTS!..it easily roasted the tires,even in thet big barge!..it too was rated at 290HP and 360 ft lbs..

The "doggiest" 454 I had was in my '74 K20 when I first bought it--engine codes showed it was originally from a '74 Chevelle "Laguna"..should have been identical to the one I had in that '74 Monte Carlo--but this motor was "lazy"..it had gobs of low end,but didn't have much higher end power for some reason..and this truck had 4.10 gears too!..motor ran OK,I tried putting a new "Speed Pro" Sealed Power cam in it,and one valve spring I found broken,along with a mushroomed tip on the valve the cam lobe fried on,but it still didn't seem to have the power the other 454's I had did..the SB 400 I swapped in actually had more power,IMO!..

The best 454 I ever drove was in my brothers '82 K30--we got it from a 1970 Impala,and added a open plenum Weiand Intake,a Holly 750,and a Competition Cam #260H,all swap meet leftovers we had kicking around..what a sweet runner that motor is!..'70 was the year with the highest compression,this one was rated at 360HP and who knows what the torque was after our add ons--all I'll say is that thing would PULL!..made all my 454's feel like a straight six in comparison!.

I borrowed that truck to buy a plow blade, and fisher plow setup and get it home--I barely touched the gas in third gear (SM465) and I FLEW up a huge hill that most cars and truck bog out on,and crawl up at 35-40 mph!..I started from a dead stop at the bottom,was going 60+ mph in a matter of seconds,and I was afraid the plow was going to slide right out of the bed,it accelerated so fast!..

The fact the truck had 4.56's didn't hurt either,and we loved towing with that truck--rarely had to downshift,it would pull like a train in 4th gear,even uphill slowly!..that motor still sits under my brothers workbench,been there 8 years,awaiting the next neat old GM vehicle to propel!...

Had a scary drive in a friends '69 GTO that he repowered with a '69 Chevelle's SS 396/375 HP motor once--he was drunk,so I drove him home--I booted it in third (had a muncie in it)..and wound it up on the highway--just as the secondary barrels opened up,I looked at the speedometer,and we were going well over 110 mph!..and I still had 4th gear and lots of pedal left!..

I owned an identical '69 GTO with the pontiac 400/TH400,and his car would DUST mine!..and mine was no slouch either,I could get it to 60 mph in just over 6 seconds.!

I like the 427 motors best--they will wind up much higher without destruction thanks to its shorter stroke,but doesn't have quite the low end grunt of a 454..but I've only seen a handfull,and all the ones I had rides in, or driven loosened my bowels!..had one ride in a '68 Vette with one I'll never forget!..

 

[01maroonz71]

holy long reply batman!!!!!!
one day ill have a big block myself...one day.

 

[rjfguitar]

one day ill have a big block myself...one day.

It's not something to get excited over..... they suck gas and still feel like you are stepping on a frog when you floorboard them. Compared to a small block, they just make more noise.

Now, if you had said....

"one day I'll have a turbo diesel myself...one day"

I'd completely agree.