350 or 454?

[Wrecked1982]

so ive been running a 81 c30 350 4 speeds but this fall i scored on a very clean 85 k35 454 th400 . at first the 454 consumption was terrible .20$ of fuel for 20 minutes of driving. after rebuilding the carb. and set timming properly id say it must have gone haft better at least on fuel consumption. it now runs very well and respond very fast .but when going down the road when i smash it down it kicksdown and accelerate normaly and thats it . i dont event feel beeing pushed back in the seat . its almost like my old c30 has as much torque. by the way its the first 454 i drive ever, so maybe i was aticipating too much from a bigblock?? should i keep it that way or should i swap for the 350 witch seems to be as powerfull as the 454 and cost wayyyyy less fuel......

[INSIDIOUS '86]

Well 80s big blocks had like 220-240 hp and were rather lethargic so really all the we're good for was towing and eating gas. If you do a cam swap and raise the compression and add some headers with a good carb and intake you should see some nice gains. As for your small block it's lighter and has a smaller crank and can rev quicker and higher. So think about whether you want to build the bbc or keep the sbc. As it stands right now they both have prob around the same hp. So unless your towing why staunchly bbc?
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[Wrecked1982]

ill swap my c-30 wrecker bed onto it so its gonna be mostly towing but if the 350 will be as much as the 454 in the end i just wanna spend less on fuel, if it takes me 3 seconds more to get to 100km/h than with the bigblock
i dont really care

[Junqueboi]

You should feel an obvious difference between the two engines. 350s are great engines but the 454 should feel a lot stronger. I speak of my experiences as currently an owner of a 454/4spd C30, 454/400 C20, 350/700R4 C20, 454/400 C15, 350/350 C15, 305/400 C20, etc.

My 454 C15 gradually started losing power & it seemed real sluggish...the carb was fine, it was in perfect time, etc. Turns out the vacuum advance plate inside the distributor froze in place... I never noticed it when setting timing at idle but it was so doggy.

I replaced the distributor & the truck totally came alive & ran like a scalded dog. So check the vacuum advance... take the cap off & try to pull the rod with your hand or some needlenose pliers. It should be stiff but not binding. a LOT of SBC & BBC distributors I have run across are seized up.

[SSC's76]

Its your call depending on what you do with the truck. you may not rice a seat of the pants difference but even a dog 454 will cruise down the highway and feel like its just putting along no strain at all compared to a 350. id suggest putting a mild cam it in bring it up a notch on the power. my previous 383 was pushing close numbers to my 454 but the 454 feels alot stronger

[donut]

Gearing the same?
Drove an old 460 Ford that if I hit the gas at 55mph, all it would do is make noise. Rear had very low towing gears. At idle, in gear, you could out-walk it.

My old k-20 vs my c-30 there is a big difference, both geared the same, tire size close. K-20, 350 C-30, 454. The straight 6 in my wife's '03 Trailblazer feels "peppier" than both of my trucks.

[Wrecked1982]

well i will sure have to check out that vaccum advance and when ill swap the bed ill try it to see the difference if its just a bit more than the 350 and costing too much fuel ill go with the 350 , the previous owner had it regearded to 3.73 as he said 4.10 was way too much reving at highway speed

[Goldfinger]

with my experience a 454 stock feels almost equivalent to a 350. until its got weight strapped to it and then it shines.

[Wrecked1982]

yeah this is how i feel right now having tried the 454 but did not tow anything yet

[m00n1957]

you probably have "peanut port" heads on your 454, they run out of breath at about 4500 rpm due to the small ports. everyone has a 305 or a 350, i like the rat motors myself.

[BigBlocksRule]

Tweak that 454. It has less than 8:1 compression and probably has peanut port heads. Find some true ovals - 781's are the most common - and have 'em milled to get the chambers down to around 110cc's. Small cam, something in the 215 - 220 range, tune it and let 'er rip.
But I'm kinda partial myself...

[76Charlie]

Why do people hate peanut ports? Even when you stomp on it, mosty likely your auto tranny shifts around 3000 anyway? Why would you need to go higher than 4500 rpm for commuting, my rebuilt 454 with peanuts has roughly 300 hp and close to 475+ ft. lbs... <---- torque, the reason big blocks exist

[BigBlocksRule]

Torque at higher rpm's = higher hp.
My tranny doesn't shift at 3k, more like about 5K when I'm on it.
Peanut port heads are great for what they're intended for - lots of bottom end grunt, great for towing. They get better mileage as well and work better with a carb than other heads due to the strong signal to the carb.
I just don't like my engine to sign off making power at 4000rpm's, which is about what peanut port heads do. A well built towing combo with large ovals will outpull a peanut port engine above about 2500, all the way to 5 grand.

[76Charlie]

Originally Posted by BigBlocksRule

Torque at higher rpm's = higher hp.
My tranny doesn't shift at 3k, more like about 5K when I'm on it.
Peanut port heads are great for what they're intended for - lots of bottom end grunt, great for towing. They get better mileage as well and work better with a carb than other heads due to the strong signal to the carb.
I just don't like my engine to sign off making power at 4000rpm's, which is about what peanut port heads do. A well built towing combo with large ovals will outpull a peanut port engine above about 2500, all the way to 5 grand.

haha! miss type 5k is what i meant. I don't know, I guess i like peanuts because that's all I got, all i've ever used, and they are cheap SOB's

[BigBlocksRule]

I may actually use a set on a tow rig I'm building. I don't care to hotrod it, but would love that massive low-end grunt.

[79k30dually]

I've found the difference between a big block and a small block is when you shift into high gear when you're fully loaded or over loaded. good luck, Ron

[chriskent5150]

So over all what is the better motor, I want to build one for a street rod. Any input would be great.
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[76Charlie]

Big block or nothin bro!

[HarleyHauler]

Originally Posted by 76Charlie

Big block or nothin bro!

X2 .. especially if you plan on towing anything..

[79shortbed]

I mean if you don't want that 454, I can take it off your hands

[chriskent5150]

I haven't found one yet mt truck still has the stock 250 strait 6 in it. This will be my first build do was just seeing wich would be better. Is a 454 harded to work on?
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[tucsonjwt]

I have owned both 454 and 350 squares. Typical gas mileage in the city was 9-10 mpg on both engines. 12-13 mpg for both engines on the highway. With and 87 fuel injected 1/2 ton with 3:08 rear I think you can expect 17-18 highway. I had a 4.8 2010 ext. cab. Sierra with 3:23 rear which only got 18.5 highway.

[BigBlocksRule]

454's and their associated parts are heavier, but that's the only thing that makes 'em "harder" to work on. Valves are canted toward the center of the cylinder, so the heads breathe a lot better. In an apples-to-apples comparison, 350 vs 454, cubes = torque = more power throughout the range. Well thought out, cammed and tuned, there's no reason a 454 shouldn't get reasonable fuel mileage.

[Wrecked1982]

what cam is best recommended for fuel economy to leave the rest totaly stock?

[76Charlie]

I've noticed that, when I had my 350 I was getting maybe 6-8mpg, now I'm getting 4 (motor still breaking in) so I expect around 8-10, and that's well worth it for the crap load of power I have now