1966 Big Block swap - Impala Tech
Engine General Engine Discussion.

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post #1 of 16 (permalink) Old 11-15-2018, 07:17 PM Thread Starter
 
 
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1966 Big Block swap

I'm currently looking into getting a 454 and a 4 speed from a 1970s or 1980s truck for my '66, currently equipped with the stock 283 powerglide. My goal is to have a fairly stock build (i.e. no headers, racing cam, efi) with a little more torque than the small block puts out.

My question is what parts will I NEED to replace for this swap. It's my understanding that the trans crossmember is the same. Will I need new motor frame mounts? Will truck mounts work? If I keep the stock 8.2" rear end, is it going to explode if I do a burnout? Throttle linkage? I need to keep costs down, so I'm hoping to salvage as many parts as I can from whatever truck I end up getting.

1966 Impala 4-door Sedan
283 V8, 2 speed Powerglide Automatic
Black.
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post #2 of 16 (permalink) Old 11-15-2018, 10:57 PM
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Quote:
It's my understanding that the trans crossmember is the same. Will I need new motor frame mounts? Will truck mounts work? If I keep the stock 8.2" rear end, is it going to explode if I do a burnout? Throttle linkage?
It's my understanding that the trans cross-member is the same.

Yes it is.

Will I need new motor mounts?

Yes any engine over 300 horse power used the interlocking high performance motor mount

Will I need new Frame Stands for the Motor?

No! The ones bolted to your frame work fine. Only the Camaro and the Nova required changing the Frame Stands for the Motor to raise it to clear the steering gear box ad shoved it over an inch to the passenger side to clear the clutch and steering column as well as the gear box.

Will truck mounts work?

No.

If I keep the stock 8.2" rear end, is it going to explode if I do a burnout?

Probably. But the tire is the weakest link, so it will slip first. However a three block long burn out will probably weld the axle to the wheel bearings (snapping the wheel off at the end of the housing) as they are splash lubricated and will run dry if you push your luck.

Throttle linkage?

Go with late model cable linkage. The truck that has the donor engine will have a throttle cable set up for a Quadrajet that should bolt on to another Quadrajet, but will require a new aftermarket throttle cable bracket for a Holley or a Carter AVS.

Big difference in BBC engines from 1974 through 2001. They all had "peanut port" heads that started out at 210 cc but dropped to 190 cc. From 1965 through 1973 Chevy used the oval port head (peanut port is round) that measured 230 cc, or the 320 cc rectangular port head. Bigger difference was that starting in 1996 Chevrolet redesigned the BBC introducing the Gen V one piece rear main seal engine. All of these blocks are four bolt main with a cast iron crank. It will not have a clutch ball pivot point (because the engines were all in front of an automatic) and it will not have a provision to bolt on a fuel pump because they were all EFI. Additionally Chevy changed the cooling system so that the older Mark IV heads can not be used (they bolt on but you will have a water fall in the lifter valley as the coolant holes do not line up).

What you want is a 454 out of a 1970-'73 Impala, Corvette, or pickup truck with a manual transmission.

Big Dave
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post #3 of 16 (permalink) Old 11-16-2018, 12:54 AM Thread Starter
 
 
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Thanks for the info! It may be a little tricky to figure out the throttle linkage.

I'd definitely prefer a 1969-73 engine but I'll have to take what I can get as far as price. Do peanut port heads have poor performance? I don't really understand the differences between those and oval port. More cc's means more flow, right?

1966 Impala 4-door Sedan
283 V8, 2 speed Powerglide Automatic
Black.
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post #4 of 16 (permalink) Old 11-16-2018, 06:36 AM
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I'm not absolutely sure, but most truck 4-speeds are of a different design then the type we use in cars. They have a granny gear in them that makes them a 4 speed. Under unloaded driving you don't even have to use that gear. These boxes are bigger than a T-10 or Muncie and I don't think they will fit under your tunnel or even use the same cross member.
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post #5 of 16 (permalink) Old 11-16-2018, 07:18 AM
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All engine power is in the heads. You can gain 30 horsepower with oval port heads over a round port head, add another 30 horsepower if you increase the valve size of the oval port head to the size of modern aftermarket heads (2.25" intake/1.88" exhaust). Modern ports and bigger valves found on aluminum aftermarket heads can add 230 horsepower to a stock smog era BBC (1973-2004). Just keep in mind bigger isn't always better when it comes to port size. It takes a minimum of a 496 cubes to get rectangular port heads to work on the street.

https://www.hotrod.com/articles/bolt...ome-big-block/

He didn't mention a truck four speed (Muncie SM465 or a Borg-Warner T-96) that will not fit in a car body (they barely fit in a one ton pick-up as they ere designed for a medium duty truck (duce and a half).

I was assuming a Muncie car tranny or a Borg-Warner Super T-10.

Big Dave
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post #6 of 16 (permalink) Old 11-16-2018, 11:14 AM
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It is quite easy to achieve 400 + lbs ft of low end torque in a small block (383). No high rev cam, no headers, nothing more than basic new 'production' type parts. The initial outlay for the engine will be higher than a used BB, but the install should be less.

Costs offset? Don't know. I'm simply identifying and alternative to a BB that you may wish to consider.

I have a 383 in my '63 that was dyno'd at 385 hp at 5400 rpm, and 440 lb-ft at 3800 rpm. The torque is 400 lb ft at 2500 rpm (the lowest rpm noted). It has aluminum heads and intake manifold, a 600 cfm Edelbrock 4 barrel carb, and a cam with less than 5" lift (I'm too lazy to look up the specs). I have the 2 1/2" ram horn exhaust manifolds and basically stock exhaust system (2 1/2" to mufflers, 2" tail pipes).

I agree with Dave about tires. I purposely only have 215x70x15 tires because I want the tires to break loose before parts do.

Certainly the BB has greater potential than the SB, but with today's advanced heads, achieving 'old' BB torque from a sb is easy.

Just food for thought.

Pete
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post #7 of 16 (permalink) Old 11-16-2018, 11:39 AM
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I agree with Pete. Here is a "396" in SBC clothes that makes more power than any 396 ever made; weight is 120 less than a BBC, and everything you have now to bolt it in place will bolt up to this engine.

https://www.summitracing.com/oh/part...eprint-engines

Start pricing the cost of the cheapest BBC rebuild and you will discover that this crate engine is far cheaper, and it comes with a three year warranty.

Big Dave
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post #8 of 16 (permalink) Old 11-19-2018, 01:57 AM Thread Starter
 
 
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I was thinking of an SM-420 or SM-421. It was my understanding that the SM-465 is designed to bolt to a transfer case, and wouldn't be compatible with my setup.

If I had the spare cash for a crate engine, I wouldn't even be considering buying a truck. If I end up going this direction, I'll definitely look into large port heads and intake manifold. I would need to get the engine running in the car before I bolt on any aftermarket parts.

I'm not looking for 500+ lb-ft. by any stretch, just something that will pull from stoplight to stoplight (which my current small block just barely manages). I'm also considering 383 or 400 small blocks, but I figured that a big block could make more power with less modification.

1966 Impala 4-door Sedan
283 V8, 2 speed Powerglide Automatic
Black.
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post #9 of 16 (permalink) Old 11-19-2018, 10:29 AM
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We are talking truck. I thought you were putting this into a '66 full size. Well luckily for you 1966 was the last year that Chevy used a SM420 in a light duty pick up (3100 or 3200). You will need the bolt in floor panel used to clear the ten inch tall transmission. The flat one used for a PowerGlide or three speed manual (once again I would use a Muncie four speed from a another truck. It will have a rear transmission housing to fit a truck that is three inches longer than the car version). In addition to the tranny cover that is part of the truck body you will need a longer drive shaft as it bolts to the rear of the very tall but short tranny. All of these parts I found in a local truck salvage yard 46 years ago.

Additionally the cast iron bell housing is for a 12 inch flywheel and clutch. You can use an ii inch clutch and flywheel (they don't make a flywheel for a 454 as it was never installed in a first or second generation CK truck); but you will have to machine the aluminum 11 bell housing to bolt up an SM420 transmission as the hole size is different in the back of the bell housing.

I had a 3600 HD (one ton suspension) 1961 Apache that had the old four corner motor mounts. I found a SM420 transmission in a dump truck (complete with a hydraulic pump attached to the PTO that I used to power a crane I built in the bed). I replaced the 235 six with a SBC 400 and bought a SBC 11 flywheel as a service part (Chevy made it just for transplanting a manual behind the 400 that left the factory as an automatic only).

Big Dave
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post #10 of 16 (permalink) Old 11-19-2018, 05:27 PM Thread Starter
 
 
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Okay. To be clear, I'm planning to put a truck engine and transmission into a 1966 impala, and I want to know what modifications will be needed, and which transmissions will/will not fit.

Which transmissions am I likely to find in a later (1970's-80's) truck, and will those transmissions fit into a 1966 full-size car? If I need a different transmission than what comes stock in a truck, which transmission should I look for?

1966 Impala 4-door Sedan
283 V8, 2 speed Powerglide Automatic
Black.
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post #11 of 16 (permalink) Old 11-19-2018, 06:18 PM
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SM420 was discontinued in 1966. Which is why no 1967 and up truck had one installed. It is basically a heavy duty three speed with Granny Low only used if you are off pavement trying to get a heavy trailer rolling. It will not fit in a car body despite all of those images by Ed Roth showing his monster shifting one in their hot rod. It doesn't even fit in a light truck body which is why GM dropped them, using them only in military vehicles through 1977.

Like I said it won't bolt up to anything but a really course spline 12 inch clutch in a cast iron bell housing made just for this transmission. That bell housing is out of a school bus or dump truck and it will not fit in your transmission tunnel.

Newer GearVendor four and five speeds are equally huge designed for a 14,000 GVW vehicle. They do have a fully synchronized gear set but once again they will not fit in a car body.

Your transmission choices are a Borg-Warner T-16 3 speed manual (rare as hens teeth used by short dirt track racers), a Borg-Warner T-56 6 speed manual (double over drive), a Tremec TKO 600 5 speed OD Manual, a Borg-Warner Super T-10 four speed manual, a Richmond five speed gear box (not an overdrive as it has five forward gears all spaced very close together), and a Muncie M21 four speed. All of these are rated at 350 to 450 lbs./ft. of torque so a BBC won't break it. None of these are cheap.

In terms of an automatic you can choose from a TH400, or a hand-built out of billet unobtainium TH350/700R4/200R4 automatic. Only the TH400 is affordable by people like me. Any one who tells you that he can build a non-TH400 automatic to withstand 450 lbs./ft. of torque is lying to you or is going to charge more than you paid for your house to buy it.

TH400 is all cast iron inside (why it weights a ton) and can handle a BBC because Chevy designed it to work behind a 427 in a Corvette. The 454 makes more torque but back in the days when engineers used slide rules they built them 50% stronger than required to last through the warranty period.

All of the other automatic transmissions I mentioned are all aluminum from case to internals only using steel for clutches and bands (the steel sun shell in a 700R4 might as well have been pressed out of paper mache as it will break on the first up shift). They are rated at 250 to 300 lbs./ft. of torque so a stout SBC will break them and they stand no chance what so ever of living behind a BBC and a heavy B-body.

That 454 truck engine only makes 230 horsepower (while a bone stock base 327 made at least 275), but it makes 450 lbs./ft. of torque. Chevy engineers designed it as a cheap alternative to a diesel engine in their pick-ups; (competitors diesels made 650 to 700 lbs./ft. of torque which is why the BBC died).

Big Dave

Last edited by Big Dave; 11-19-2018 at 06:26 PM. Reason: Torque breaks stuff
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post #12 of 16 (permalink) Old 11-19-2018, 10:20 PM Thread Starter
 
 
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So which manual transmission did chevy trucks use after 1967?

1966 Impala 4-door Sedan
283 V8, 2 speed Powerglide Automatic
Black.
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post #13 of 16 (permalink) Old 11-19-2018, 11:34 PM
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Muncie M20 if they had a four speed. Almost all factory manuals were a Saginaw three speed. Most automatics where a TH400 or a PowerGlide. An empty pick-up only weights about 400 pounds more than a full size car. They just have a lot more carrying capacity.

Big Dave
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post #14 of 16 (permalink) Old 11-20-2018, 02:43 AM Thread Starter
 
 
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So a post-1967 truck will be equipped with an M20, Saginaw 3-speed, TH-400, or Powerglide. Will all of those be compatible with my car? I just want to know if I can pull the transmission out of the truck I end up buying and bolt it into my impala, or if I should source a transmission from elsewhere.

1966 Impala 4-door Sedan
283 V8, 2 speed Powerglide Automatic
Black.
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post #15 of 16 (permalink) Old 11-20-2018, 10:59 AM
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No big block was put in a pick up until 1968 and then it was limited to a 396/402 but only in a three quarter ton or one ton truck, not the half ton. 210 to 230 horsepower 454 didn't appear in a pick up until 1981, because smog era 305's where being out performed by 302 powered Ford pick-ups. They were pulled out of pick-ups again in 1974 and din't reappear until 1979 through 1996. 1997 through 2001 were a Gen V engines and have a one piece rear main seal no mechanical fuel pump and no provision for a manual transmission. The 8.1 Vortec (Gen VII) where based on a tall deck block that are not even a BBC as it has no parts in common with a BBC except the water pump and the starter.

The Saginaw three speed is torque limited to 250 cube sixes and the 305. It was not used behind a 350 or a 402 because it would break. The 350 had a TH350 and the 402 had a TH400. The four speed Muncie was a user or dealer installed option as the Muncie SM465 or a New Process NV833 was installed if you wanted a four speed.

The New Process NV833 transmission was the same four speed Mopar used in their hot rods behind a 440 or a 426 Hemi; however Chevy not only changed the mounting points of the case to bolt up to a dedicated (not stock bell housing) they also changed third gear into an OD gear which made it a three speed plus OD instead of a true four speed.

You will find them in 1980-'85 Vans and light pick-ups during the period when you couldn't get a BBC in a light pick-up. Be sure to get everything from the block back and the clutch linkage as the parts are unique to this application. Note that the fly wheel is for a neutral balance 350 not an externally balanced 454. So it will work with a 402 but not a 454.

Big Dave
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post #16 of 16 (permalink) Old 11-20-2018, 06:13 PM Thread Starter
 
 
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Okay, I think I know enough to start looking for a donor truck now.

BTW, would It be possible to cut the trans tunnel out of a truck and weld it into my Impala, giving clearance for a larger transmission? Just a thought I had...

1966 Impala 4-door Sedan
283 V8, 2 speed Powerglide Automatic
Black.
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