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454 swap need advise

 
Old 03-05-2019, 02:30 PM
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frytex
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Default 454 swap need advise

I just picked up a 1980 Corvette with a running 350 engine in it. I just got offered a 454 engine fully rebuilt for a great price. I want to drop the 454 in to the 80 Corvette. here is the advice I need.

1. If I wanted to put a cam in it which would be the best one?
2. can I use the transmission that is still in the 1980 Vette? if not what would be a better transmission to use?
3. If I wanted to change over to Standard instead of automatic which trans would work the best?
3 can I use the rear end that is in the 1980 Vette? if not what would be a good rear end to install?

Thanks

Last edited by frytex; 03-05-2019 at 02:31 PM. Reason: adding info
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Old 03-05-2019, 05:22 PM
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Kevova
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BBC in an 80 you need proper oil pan, mounts, and accessory brackets. Intake may require hood scoop, not a lot of clearance. You will want a THM 400 transmission. Unless you have a donor 4speed car not worth conversion. Diff should be OK.
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Old 03-05-2019, 05:54 PM
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derekderek
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too much alteration for no gain. the only 75-up big blocks are in a class by themselves. more interesting than a small block but suspect cuz it was probably thrown together with parts on hand. and if you have to roll thru an emissions test, could be a pain.
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Old 03-05-2019, 07:36 PM
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cuisinartvette
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Try to find out what heads and piston pn it has before buying anything. Do you have info about the rebuilder?
Lots of those big blocks had super low compression like 7,8-1. Unless something was changed you dont want to put a big cam in it
A borescope down a spark plug hole can tell you a lot then plan over. May need different valvesprings too but those arent pricy
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Old 03-07-2019, 10:41 AM
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frytex
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The 454 was pulled from a 200 Chevy 3500 and is still stock< would it be worth buying it for $1500 and swapping it over.
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Old 03-07-2019, 11:14 AM
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maj75
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No. That isn’t a performance 454. It’s got crappy fuel injection and most likely no provision on the block for a mechanical fuel pump. Crappy heads. You can find a pre-‘75 454 for that money.
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Old 03-07-2019, 12:18 PM
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If you really want to put a big block in your 80 and you want to run a mechanical fuel pump and a manual transmission with a standard clutch (not hydraulic) then you need to make sure you find a MarkIV or earlier block series.
The MarkIV was the last big block with the clutch linkage pivot bolt hole and the provision for the mechanical fuel pump.
You can find a good Mark IV 454, 4 bolt main for $500.00.
I believe they manufactured the Mark IV series until 1991 which were 454, 4 bolt mains, short deck blocks with the manual fuel pump provision and the clutch linkage pivot bolt.
If you plan to run fuel injection, an electric fuel pump and hydraulic clutch then Mark V blocks will work as well.
You should also stay clear of a tall deck big block as they were manufactured for trucks and even though there is nothing wrong with a tall deck, you will limit the availability of aftermarket heads, intakes, headers, etc and the tall deck blocks could cause other clearance issues when the engine is installed in the car.
A stock TH-400 will handle most mildly built big block motors but 700R4's or 2004R's won't.
I am building a 496 for my 73 and swapping over to a TKO-600RR transmission because I wanted overdrive and no one could guarantee me that their upgraded 700R4 or 2004R would hold up under the torque of my build.
I'm installing an SST auto to manual conversion kit.
Your stock 80 rear end will not hold together behind a mildly built big block if you plan to use the car for any spirited driving.
Your stock rear end may work ok behind a stock big block if you drive it like a daily driver, but if you ever want to step on it you better pucker up before you mash the accelerator pedal.

Last edited by OldCarBum; 03-07-2019 at 12:22 PM.
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Old 03-07-2019, 01:33 PM
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Vortec 7400 has potential but I'm not sure about in this application. I would stick with a SBC.
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Old 03-07-2019, 06:49 PM
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Actually pretty nice engine. Cheap. Easy to find. Gotta run electric fuel pump. Can run OEM 502HO cam on existing roller lifter setup. Need Just make sure it isn't a gen 5 peanut head flat tappet engine. 96-00 Truck. But I don't think you should get this involved in this 80. Get the engine numbers. In a 3500 truck it could be an L18. Same engine forged crank and pistons.

Last edited by derekderek; 03-07-2019 at 06:57 PM.
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Old 03-13-2019, 02:46 PM
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bigg_un
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I would spend my money on a small block...either the one you have or replace it and upgrade the tranny...fitting a big block into that yr model is going to be costly..especially if you want to keep AC and power steering..I'm a BB fan but changing one over is a chore...I'm doing a '74 currently...other things to consider are suspension and exhaust modifications that will also need to be done...
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Old 03-15-2019, 02:37 AM
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Originally Posted by derekderek View Post
Actually pretty nice engine. Cheap. Easy to find. Gotta run electric fuel pump. Can run OEM 502HO cam on existing roller lifter setup. Need Just make sure it isn't a gen 5 peanut head flat tappet engine. 96-00 Truck. But I don't think you should get this involved in this 80. Get the engine numbers. In a 3500 truck it could be an L18. Same engine forged crank and pistons.
my 97 K3500 truck has the L29 Vortec 7.4L (454), the ports are the oval ports, bigger than the now-infamous peanut ports that were used in the SS454 truck. I think the L29 oval ports are the same size as earlier "oval ports" from the days of yore.

I have the rect ports in my C3 though, just because.
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Old 03-15-2019, 04:49 PM
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1999corvettels1
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Originally Posted by Kevova View Post
BBC in an 80 you need proper oil pan, mounts, and accessory brackets. Intake may require hood scoop, not a lot of clearance. You will want a THM 400 transmission. Unless you have a donor 4speed car not worth conversion. Diff should be OK.
How hard are the accessory brackets to find?

Will his 350 alternator and power steering pump fit the big block brackets, if not and he gets new or rebuilt alternator and PS pump, will the pullies off the 350 parts fit, and align properly with big block stuff?

Also possibly going to need stronger springs in the front of the car.

I swapped in a 454 and TH400 into my 1965 C10 short bed pickup, got the engine and transmission from a 1974 C10, that was really rough, bought the whole truck.

Used the brackets, accessories, pullies, mounts, frame stands for mounts, drive shaft, starter motor, etc.

First time I drove truck, pulled out of the garage and gently pressed brakes, the whole front of the truck leaned way down, it felt weird and unstable.

Ended up putting in CPP big block springs, that fixed that.

There is a lot of little stuff that seems simple, but starts adding up.

It would be best to buy a donor vehicle that has the big block and TH400 with all the parts complete, then you can save time and $$.

By the way, I ran engine numbers in my "454" after swapping into 1965 C10, it turned out to be a 1968 396, the 1/2 ton pickup version with 310 HP.

Guess the original 454 in the 1974 truck was blown, or needed a rebuild and someone put the 396 in.

I did this in 2004, and dream of putting in a LS engine and overdrive. Lol

Last edited by 1999corvettels1; 03-15-2019 at 04:51 PM.
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Old 03-15-2019, 05:55 PM
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Vortecpro (Mark) has done some impressive builds wiht the peanut port heads, requires a lot of talent to diy though.
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Old Today, 04:48 AM
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rpoL98
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Originally Posted by 1999corvettels1 View Post
How hard are the accessory brackets to find?
reproduction brackets and pulleys are readily available, but since these are CORVETTE repro parts, they're not real cheap, but at least they're not in the Porsche-BMW-Mercedes price range. I think a set of brackets to mount your alternator & power steering pump will run about $200. you still have to get the right Corvette pulleys, which again are available repro. if you're going to run PS, then you need the PS pump reservoir where the fill is canted forward, otherwise you'll never get the cap off of the reservoir. you'll need the cast iron keyway PS pulley. and the short water pump. JIMHO get the SWP with the 3/4" pilot, not the 5/8" pilot.

the long water pump necessitates the extended crank pulley which interferes with the cross member. some folks do it that way but then wonder why their engine has to sit 3" higher and then they can't close the hood, etc. so, short water pump to save yourself a lot of troubles, unless your name is Bubba.

This is all standard procedure of how Chevy installed a BBC into a C3 back in the 70's. the C3 engine compartment is essentially unchanged through 1982. it really is cookbook. straight forward bada bing, bada boom.

there's quite a few threads in this forum on "how to" BBC into a C3. you wouldn't be the first by any means.
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Old Today, 07:15 AM
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With everything out of the engine compartment of my 80 except the engine, it looks like there is room for a big block. I'm not going to fall for that trap, though.

The correct transmission is anything that has at least 4 speeds and 3 pedals. Do that swap first, and you may find you don't need more power to enjoy your sportscar.
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