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383 or 454?

M

Mountain_man

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Ok I'm trying to decide if I should build a 383 up or get ahold of a 454.
I can get my hands on a 454 in good shape with tbi however I also have a 350 block in good shape to convert to 383. I have ability to do either just would like some guidance. What would I be looking at with the 454 swap? I've already got the 4l80e trans but could use some help here. Thanks.
Josh
 
454 period. Only issue you may have is the power steering pump as they are specific to big blocks. Accessory brackets can be a pain sometimes, but they are available. I swapped a 454/4-speed in my truck, it's pretty much stock, it has all the power that I need, and think it gets better mileage than the 350/700 that was in it.
 
I was in the same delima. I have a 383 in my K5 now. my thought was weight. Wanted to keep weight down as much as possible and a 383 makes good torque, not like a 454 but good none the less. I picked up a 454 from another member for my burb. But now I have decided to use the 454 for my K5.

I will just throw all kinds of Aluminum at it to lighted it as much as possible. A big block with all aluminum accessories, heads and water pump is only about 9lbs heavier then an all steel small block. Of course if you throw all kinds of aluminum on a small block you have a really light motor. I though about that too, but in the end I'm going to run the 454. It's going in my 73' so I can build it too, no smog worries. It's TBI motor, I have the ECU, and fully unmolested harness.
 
Before I swapped the 454 in my truck, it had the same springs and axles under it. My 454 still has the stock iron intake, but lost a pound with an aluminum timing cover.....lol. Anyways, the truck rides better with a little more weight on the front. AFA wheeling goes, never wheeled it with the small block, but with the big block you can leave it in 1st on touch the gas. And I NEVER use 1st on the road, don't need it. Only time might be starting out on a steep hill or something like that.
 
454!When I swapped from a 400 to a 454 in my old '79 Sub.I gained mileage and power was great.
 
just make sure your cooling system is up to par for the big block...
 
Ok so it seems 454 is the way to go. I'm not worried about cooling as a 4 row with dual electric. The 454 should mount straight up to the 4l80e I believe? Any other mods as far as frame or anything goes? I know diff motor mounts but I also know their is enough room under this hood for it. Well I'm glad you all are around to help me with this as I would have just dropped a mod'd 350 or gone full 383. These things are heavy though and makes perfect sense 454 would make more.

Any other info or things to look out for as far as costs go in dropping this thing in? Seems to be a near perfect fit other then crossmember.
 
427. Only problem is that they are pain to get ahold of from what I've seen. and its kinda the best of both...
 
All the vehicles that I swapped to a 454, I NEVER had to change the motor mounts. Yeah the big block mounts might have thicker rubber for isolation or whatever, but I never had an issue. Even my old 78 Malibu with an alum. headed 468 making aboot 550 horse used the stock small block mounts.

The 454 will bolt to the 4l80, but if you have a TBI you will need the 454 chip to make it run right, or if you have a stand alone computer for the tranny...
 
Big Block HP

So I am thinking about getting a 454, building it up, and swapping out the 383 in my truck. What kind of HP numbers are you running/estimating out of your big blocks?
 
Mine is stock far as I know, bought it ready to go. It's spotless on the inside, so I know someone was in there at one point since 1975.

But in the smog years of 75', motor probly 275-ish horse, and 350-ish torque. This is just a guess, don't really know for sure. I know that this motor in my shortbox is NOT lacking in the power department. 2nd gear starts all the time, I haven't tried but I know it will smoke the crap out of them. 4th pulling any hill and not having to down shift.

Gas mileage isn't really that bad, but at least now I have the power to do pretty much whatever I want, mileage doesn't bother me.

Getting excited about getting my crew going with the 427 tall deck, guess these motors are close to 500 ft/lb of torque....
 
With the 454 I got from another member with an aprox estimated 120,000 miles on it, should I go thru the motor? atleast pull it apart, mic everything, If tollerances look good, give it a quick hone and re-assemble with all fresh gaskets?

Maybe pop a new cam in it since my K5 is a 73' and I don't have to worry about smog? Just has to be TBI compatable.

Anyone run a performance throttle body? good decision to replace or run stock TBI?

I would like to put Aluminum heads on it to at some point, bolt on out of the box heads. Any suggestions? Edelbrock heads good?

If I put heads on it should I go ahead and have the motor gone thru, re-machined and ballenced & blue printed?
 
Is this the motor Greg was selling? If so at least you know the history of it,I think 4X4 High knows a bit about that motor also if it's the one I was thinking about buying. I would swap it in,work out any fitment issues etc, then decide what if any improvements it needs. heads and cams IMO are best to purchase /swap in together, that motor should run great just the way it is. Stock TBI is a much simpler starting point than aftermarket stuff, start with the basics and upgrade as you break/learn more about the stuff. Wish I had done things simple like that to begin with.
 
pismorat said:
So I am thinking about getting a 454, building it up, and swapping out the 383 in my truck. What kind of HP numbers are you running/estimating out of your big blocks?
Click to expand...


These are my projected #'s from a Dyno 2000 program.
9:1 pistons. Comp Cams Solid Extreme something..553/.563 and 230/240ish duration @ .050

 
I would say before you put it in, pull it apart and throw in a new cam and heads then get a chip burned for it and you will be good.
 
I went 383 because I already had a good set of small block heads, intake, and headers that I put on before the 350 blew. I would have gone big block if I didnt have all that stuff that was essentially new.

If I were doing it over though, I'd go 6.0.
 
Get the good motor mounts. I would trash the small block mounts real fast. The poly inserts are better but they died after a few years. I built my own mounts that are like the DIY4x4 and the OffRoad Design ones.

Mines putting out about 500 horses or so.
 
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