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Old 09-14-2004, 01:16 PM
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Swapping to big block chevy

Hey everyone i haven't posted on here in a while but i have a few questions. I have a 1977 monte carlo with a 350 chevy in it i put a cam and intake on it so far, but i just came across a 454 big block from a friend. The motor runs awsome but it is completely stock. The motor is also a 1977 block in a huge duelly truck. What kind of horse power and torque #'s would this block put out from factory? I was also wondering about motor mount problems would i have to buy a mount kit or will it just blot up?


Thanks for ur reply's

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Old 09-14-2004, 07:01 PM
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'77 454 Specs

I've attached a simulation of approximate performance you'll see out of that 454. The sim isn't perfect, but it's close to what I remember reading.

I've got a '77 454 that's out at the machinist right now being stroked to a 496 (I'm putting it into a '55 Chevy 1st-Series Pickup). If you care, you can check-out an ebay auction I did a month ago, there's lots of pictures of that engine:
http://cgi.ebay.com/ebaymotors/ws/eB...tem=7913050201


The motor mounts don't look anywhere-near the size of small-block mounts, although they're probably in the same location on the block. I'd guess from the mounts-back, the 350 and 454 are the same, but from the mounts-forward the 454 is significantly longer (meaning you might have trouble with fans/pulleys). Personally, if I were you, I'd bag the idea of putting that 454 into the Monte, unless you intend to rip the engine completely apart, replacing stuff like the intake (about 50#, believe it or not), heads (I'd guess close to 65# apeice) and exhaust manifolds.

The 454 has awesome torque (that's why it's in a dualie), but it's way too heavy and can't breathe worth a crap at WOT... I'd guess your 350 would outperform the 454 real-world (unless your goal is to put a plow on the front or a hitch on the back).

Now, if you're looking to replace everything (like I'm doing... crank, heads, intake, headers), you could probably make a brutal Monte. I'd guess my '77 bare block weighs as much as a completely assembled 350.

Good luck!

-Kustomizer
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Old 09-14-2004, 08:03 PM
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If you leave the 454 all iron and you compare it to an aluminum intake'd 350,you are looking at about a 250# difference.The 454 in the pickup is not a hot rod engine,but it will still outrun a stock 350,and it will also bolt right into place of the 350 on the same mounts as your 77 monte already has.It will bolt to the same trans too.The bigblock is longer in how it hangs foward of the motor mounts so the fan will be closer to the radiator,but since there is about 3 feet of dead air in front of the fan on your Monte,I would bet that this wont be an issue.There is a bigblock specific fan shroud for bigblock monte carlos since it was offered up until 1976{your car is the same as a 76 only it was never offered with a bigblock},but if you cant find one,I believe you can modify the stock piece.If your fan shroud has ribs running around it like I remember some of them having,you can usually get away with removing just the material beyond the last rib and presto,you have a bigblock fan shroud.
As far as I know,all the 73 thru 77 GM mid size cars had A/C boxes that would clear a stock bigblock with low rise calve covers and exhaust manifolds.The truck manifolds will fit your swap,but you can also use headers from a 70 thru 72 bigblock camaro.If you buy the Hooker compitition headers for the Camaro,it will come with instructions on how to notch the engine mount bracket on the later engine mounts so that they dont hit the headers.You have to do this mod when you use those headers on 73 and later Camaros too.The job can be done with a hacksaw if you really had to,but a sawzall makes it way easier.
With an aftermarket intake and tall air cleaner the bigblock may not fit under the stock monte hood.A good intake for this swap if you have no money would be a early 70's low performance 402 intake since they have no EGR provisions and are very low profile,and they are also a large oval port which will help flow despite the mismatch,and they are usually sold on Ebay for under $15.An Edelbrock Torker will fit under the stock hood too,but it isnt the best bigblock intake on the market,but it is lighter then a stock iron intake and will perform better.Dont go out of your way to buy one,but if you want a low buck upgrade,I am sure one will turn up on Ebay within the next few weeks since these intakes are always floating around for cheap.add a 750 carb to it and with headers you are already making way more power then any smog 350 with similar mods could make.
I hope you have all the brackets from the bigblock in the truck since you will also need the altenator brackets and power steering and A/C brackets to make this all work.If the truck had a hydroboost brake booster with a remote resivior,you can use it if you like by bypassing just the lines that go to the booster,or you could bastardize the stock smallblock pump by bolting it to the bigblock brackets.I think you need to remove the pump pulley for this job which is a bit of a pain in the butt.
If the 454 is a good running engine that is mechanically sound,you would rework it a bit while it is out and end up with a lot more power then you might expect.I would tear it down to a shortblock and replace the oil pump.Have the heads cleaned up and a valve job done.Buy an entire cam kit with springs lifters and timing set and swap it in along with new stock stamped rockers.I would try a cam like the comp 268 degre hydraulic since this is as big as you want to go with the smog heads.With a used torker intake,750 carb,headers,and a good tuneup to the stock HEI ignition and this engine will be a bear.If you do nothing else,replace the timing chain and oil pump with new stock replacement units since these are 2 items that can make a good engine die an early death when you drive it with a lead foot.
Good luck,and let is know how you do with the swap.
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Old 09-15-2004, 07:05 PM
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Thanks for your help everyone, your information was very informative and exactly what I was looking for. What kind of torque #'s would i be getting with intake and cam combo? Also what do you mean by ...

"If the truck had a hydroboost brake booster with a remote resivior,you can use it if you like by bypassing just the lines that go to the booster,or you could bastardize the stock smallblock pump by bolting it to the bigblock brackets.I think you need to remove the pump pulley for this job which is a bit of a pain in the butt."


Also i was wondering if i should install a tranny cooler when i do the swap, for that matter how long do u think my TH350 tranny will last?, and one last thing what does ...


" intake (about 50#, believe it or not), heads (I'd guess close to 65# a peice)","you are looking at about a 250# difference"


...mean( the # sign)?


Thanks for your help its greatly appreciated
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Old 09-15-2004, 08:45 PM
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# means pounds as in weight.
It is a crapshoot as to how much power and torque this thing will make,but with the 268 cam kit,a torker intake and headers,on an otherwise good running 454 truck engine you might be able to wring 400hp out of it,and it would be very mild,and pretty much idle and run like stock.
As for the hydroboost brakes,I would think you had them on the truck.On most cars,the power brake booster is a round canister located between the master cylinder and the firewall,with a vacum hose running from it to the intake manifold.On Hydroboost brakes,the regular vacum booster is replaced with a small assembly that mounts between the master cylinder and the firewall and has hoses going from it to the power steering pump.In the case of hydro boost brakes,the power steering pump is actually providing the power assist to the brakes compared to the normal passenger car setup which uses engine vacum to power up the brakes.If you ever hop into a heavy duty pickup{and some station wagons that have a tow package},you can quickly tell if the vehicle has hydroboost brakes.With a hydroboost setup,the pedal will feel firm,but if you stand real hard on it,it will go all the way to the floor,and you will hear a noise coming from under the hood that will sound like you have the steering wheel turned real hard in one direction{You know the groaning noise the power steering pump makes when you are parking in a tight spot with that Mostercarlo}.The power steering pump is different on a hydroboost car,but you can bypas the hoses on the pump and just use the hoses that go to the power steering box to make the power steering work.On the hydroboost setup,the cap where you add the power steering fluid is actually up high on the driver's side of the engine,and there is a box{called a resivior} that holds the power steering fluid and a hose that connects it to the power steering pump which is located down low on the driver's side of the engine,this is done because the hydroboost brake booster is mounted up high on the firewall,and with a regualr pump,the fluid would drain out of the booster and overfill the pump every time you shut the engine off.The Hydroboost pump will look just like a regualr GM power steering pump only without the tin resivior around it as is found on a passenger car application.You can take your hydroboost pump from the bigblock and the regular pump from the smallblock,and put them on a workbench alongside each other.You will notice that the mounting brackets for the pumps are different,but that the pumps are similar.You can access some of the bolts through a hole in the power steering pump pulley so that you can remove and swap the mounting brackets on the pump,but I think you need to remove the pulley on the pump to get all the bolts out.I got about halfway through a job like this once and then realized I knew where I could get a regualr bigblock power steering pump,so I just scrapped the bracket swap idea,but I do remember a little bit of how it worked.
Let me know if you hav any other questions.You can Email me at Racer7391@aol.com.
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Old 09-15-2004, 09:30 PM
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My brother had a BBC once.

Bored (468)
750 holley
weiand intake
hypereutectic pistons, giving him 10:1 compression
lunati cam .... not certain which one but it idled like a funny car
stock heads....again unsure..but they were the oem BBC heads people want (what ever that means)

It made 470 hp and 517 lbft of torque on an engine dyno, the torque actually came in strong in the lower rpms and stayed strong across the graph. I put the engine in his s-10 blazer and he used it as a daily driver, instant throttle response no matter when you punched it and a rough idle, didn't get much better.

Doesn't take much of anything to get the BBC to make power.
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