Big Block swap (work in progress)
#1
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Car: 1994 Z28
Engine: 355 LT1
Transmission: T56
Axle/Gears: 3.42
Big Block swap (work in progress)
Woke up this morning, stepped outside and it was the perfect temperature to motivate me to start my new project.
Yanked out the tired old 305.
I was amazed at this car having no visible rust anywhere... except the floorboard by the brake peddle where they commonly get rust.
I think I went a little overkill on the "dimple" in the firewall... this way attempt number one and I smashed it back another 2 or 3 inches after this.
Bolting in the bellhousing, I am aware the carb is on backwards.
Clearance is a good 5 inches in the back:
Motor is a 454 bored .040 over, 224/234 duration cam, ported 366 heads, steel crank, forged rods. Have a nitrous system set up for a 100 shot that I'll be using. Hood clearance is perfect with a 5.5" cowl.
It's a work in progress, I still have to put on the passenger motor mount and bolt both motor mounts and the torque converter in place. Also gotta tighten up the bellhousing bolts, make room for the headers, fuel line, radiator, fans and wire my ignition. I honestly think it was easier to get the big block in the car with the automatic trans then it was to get the small block in with the T5. Took five minutes to move the firewall and remove wiper motor.
Concerns:
Should I be concerned with the crank pulley sitting extremely close to the sway bar? Like it's only about half an inch above it. I was thinking about lower the sway bar with a few washers.
Power steering pulley needs to be swapped with a smaller pulley.
It's not going to be a street car, can I use the small block radiator and electric fans or should I try to tuck a big block radiator in the car?
Yanked out the tired old 305.
I was amazed at this car having no visible rust anywhere... except the floorboard by the brake peddle where they commonly get rust.
I think I went a little overkill on the "dimple" in the firewall... this way attempt number one and I smashed it back another 2 or 3 inches after this.
Bolting in the bellhousing, I am aware the carb is on backwards.
Clearance is a good 5 inches in the back:
Motor is a 454 bored .040 over, 224/234 duration cam, ported 366 heads, steel crank, forged rods. Have a nitrous system set up for a 100 shot that I'll be using. Hood clearance is perfect with a 5.5" cowl.
It's a work in progress, I still have to put on the passenger motor mount and bolt both motor mounts and the torque converter in place. Also gotta tighten up the bellhousing bolts, make room for the headers, fuel line, radiator, fans and wire my ignition. I honestly think it was easier to get the big block in the car with the automatic trans then it was to get the small block in with the T5. Took five minutes to move the firewall and remove wiper motor.
Concerns:
Should I be concerned with the crank pulley sitting extremely close to the sway bar? Like it's only about half an inch above it. I was thinking about lower the sway bar with a few washers.
Power steering pulley needs to be swapped with a smaller pulley.
It's not going to be a street car, can I use the small block radiator and electric fans or should I try to tuck a big block radiator in the car?
#2
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Car: 86 TA, 91 B4C
Engine: 5.3, 4.8
Transmission: 4L80 4000, T56
Axle/Gears: 4.30 M12, 23.42 10 bolt
Re: Big Block swap (work in progress)
Not bad, the radiator is too small, the sway bar can come off if it is not going to be a street car and you can use electric fans if they are good ones.
#3
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Car: 1994 Z28
Engine: 355 LT1
Transmission: T56
Axle/Gears: 3.42
Re: Big Block swap (work in progress)
Incase the car sees street/strip instead of full time strip, can I just lower the sway bar with washers and longer bolts about half an inch? Stock twin electric fans off an IROC going to work?
#4
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Car: 1994 Z28
Engine: 355 LT1
Transmission: T56
Axle/Gears: 3.42
Re: Big Block swap (work in progress)
One more question, I found the closest set of headers that I have to being able to fit are from a 87-earlier big block chevy. They actually pass by the firewall and clear the starter and everything and look like they can be snugged in next to the steering column. Only problem is the tabs that stick out past the bellhousing, are those safe to shave a little bit? They don't look like they have any structural support.
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Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: Big Block swap (work in progress)
Not going to be a street car? Take the front swaybar right off. You don't need it.
Cut the tabs off the transmission bellhousing.
When I first dropped in a BBC into my car, I used a Weiand short aluminum water pump with a Moroso electric drive. It was a tight fit but it just fit behind the factory rad and dual electric fans. Switching to a pusher fan would increase the amount of clearance. I don't know how tight a tall waterpump will be.
Cut the tabs off the transmission bellhousing.
When I first dropped in a BBC into my car, I used a Weiand short aluminum water pump with a Moroso electric drive. It was a tight fit but it just fit behind the factory rad and dual electric fans. Switching to a pusher fan would increase the amount of clearance. I don't know how tight a tall waterpump will be.
#6
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Car: 1994 Z28
Engine: 355 LT1
Transmission: T56
Axle/Gears: 3.42
Re: Big Block swap (work in progress)
I'm still running the small block radiator for right now, when I fire it up I'll watch the temperature like a hawk, but I seem to have a descent amount of room from the pulleys to the fans/radiator. I plan on switching to an electric water pump soon.
Only clearance problems are the sway bar (which I'll remove) and my power steering pump pulley seems to be dangerously close to the steering box.
Now that I know I can cut those tabs, I really think I can fit the truck headers without much work. Otherwise I'll be going to manifolds.
Only clearance problems are the sway bar (which I'll remove) and my power steering pump pulley seems to be dangerously close to the steering box.
Now that I know I can cut those tabs, I really think I can fit the truck headers without much work. Otherwise I'll be going to manifolds.
#7
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Re: Big Block swap (work in progress)
Some ppl remove the power steering set-up & go with a manual box from an S10. It should have the 4 bolts on top, not 3. You use your stock pitman arm. If that interests you can read thru the many threads on the swap.
The Devestator (spelling?) went with motor home stock exhaust for a while & planned on Hooker 3rdgen swap headers.
booboosean used Patriot headers.
Check them for details in the threads- good photos & good reading.
We are also planning a bigblock swap soon.
The Devestator (spelling?) went with motor home stock exhaust for a while & planned on Hooker 3rdgen swap headers.
booboosean used Patriot headers.
Check them for details in the threads- good photos & good reading.
We are also planning a bigblock swap soon.
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#8
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Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: Big Block swap (work in progress)
I use Ed Quay large tube headers but I don't think you want to spend $1500 on a set of headers for a little 468.
#10
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Car: 1994 Z28
Engine: 355 LT1
Transmission: T56
Axle/Gears: 3.42
Re: Big Block swap (work in progress)
ok I'm done with everything except my exhaust...
I see all my header options, I don't really want to spend $500 on a set I think that's ridiculous.
What are my options as far as manifolds go? Where should the collector's be (front, middle, back)?
I see all my header options, I don't really want to spend $500 on a set I think that's ridiculous.
What are my options as far as manifolds go? Where should the collector's be (front, middle, back)?
#11
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Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: Big Block swap (work in progress)
There's a set of BBC headers for a second gen that almost fit. There are no easy BBC header swap choices for a third gen. Even finding a set of cast iron manifolds isn't easy. There just isn't enough room and a good set of manifolds is almost the same price as a set of headers.
#12
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Car: 1994 Z28
Engine: 355 LT1
Transmission: T56
Axle/Gears: 3.42
Re: Big Block swap (work in progress)
I read somewhere here about those 2nd gen headers, I'm searching for it but can I also get a link to the topic (can't find it).
#14
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Car: 1992 Camaro RS
Engine: 8.0:1 454/Mild Hyd roller/Accel DFI
Transmission: WC T5
Axle/Gears: Stock 1992 open 7.5" 2.73 ratio
Re: Big Block swap (work in progress)
I used Dorman passenger car exhaust manifolds 674-159, 674-161. They cost about $200. The passenger side required I take a hammer to the firewall to make room for the collector. Your exhaust guy is gonna have to be pretty skilled to make the down pipe on that passenger side too. Its not impossible its just really tight and it has to make a kind of corkscrew on the way to the factory exhaust tunnel.
The driver's side manifold collector isn't in a spot where you can route the pipe under the oil pan like the stock setup. My oilpan doesn't have the clearance between the sump and K member for it either. I was gonna hang a muffler on the driver's side of the trans tunnel and put the turnout just prior to left rear wheel. I'm gonna do the same thing for the passenger side.
The driver's side manifold collector isn't in a spot where you can route the pipe under the oil pan like the stock setup. My oilpan doesn't have the clearance between the sump and K member for it either. I was gonna hang a muffler on the driver's side of the trans tunnel and put the turnout just prior to left rear wheel. I'm gonna do the same thing for the passenger side.
#17
Junior Member
Re: Big Block swap (work in progress)
Hey man I'm looking to do the same thing to my 87 iroc. I am just getting the car now and I'm trying to find the motor
. Do you mind if I PM you with any questions I might have. I have done alot of research but you know how things go once you start going on it. lol
. Do you mind if I PM you with any questions I might have. I have done alot of research but you know how things go once you start going on it. lol
#18
Junior Member
Re: Big Block swap (work in progress)
Some ppl remove the power steering set-up & go with a manual box from an S10. It should have the 4 bolts on top, not 3. You use your stock pitman arm. If that interests you can read thru the many threads on the swap.
The Devestator (spelling?) went with motor home stock exhaust for a while & planned on Hooker 3rdgen swap headers.
booboosean used Patriot headers.
Check them for details in the threads- good photos & good reading.
We are also planning a bigblock swap soon.
The Devestator (spelling?) went with motor home stock exhaust for a while & planned on Hooker 3rdgen swap headers.
booboosean used Patriot headers.
Check them for details in the threads- good photos & good reading.
We are also planning a bigblock swap soon.
#19
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Car: 87 Berlinetta,work in progress
Engine: 468 BB,still in the build process
Transmission: TH350,3500 stall
Axle/Gears: 9" Ford,learning how to live under
Re: Big Block swap (work in progress)
Wouldn't want to sell one of the other 9 that you have laying around,would ya?I'd gladly buy one.
#20
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Car: 1994 Z28
Engine: 355 LT1
Transmission: T56
Axle/Gears: 3.42
Re: Big Block swap (work in progress)
I took the old motor apart for sh*ts and gigles:
And some of the last updates on this project:
Motor is totally bolted in, ignition box is wired up, gauges are all installed, starter is hooked up. All I have left is the exhaust, throttle cable, fuel regulator + line, and an engine ground. I lucked out and traded a set of long tube truck headers for a set of big block manifolds with one of my friends, I will temporarily be running manifolds off a 90's TBI Chevy 3500. The firewall clears but part of the body just hits the flanges on the manifolds, I'll be smashing it back in the morning to get the manifolds on. Then I get to fire the bad boy up! Also found a 9 inch for $100!
#21
Junior Member
Re: Big Block swap (work in progress)
It's a bolt in deal.I ran mine with the S10 pitman arm,but I've been told it's better to use the Camaro one,although I never had any problem.With the S10 arm,you have a VERY tight turning radius.
Wouldn't want to sell one of the other 9 that you have laying around,would ya?I'd gladly buy one.
Wouldn't want to sell one of the other 9 that you have laying around,would ya?I'd gladly buy one.
#22
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Car: 1982 Camaro
Engine: 555 BBC
Transmission: TSI Glide
Axle/Gears: Aluminum Moser 3.89
Re: Big Block swap (work in progress)
The small block stock radiator will work fine with either the single or TPI fan set up. I have several friends using them with 555 ci and bigger engines.
#23
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Car: 1994 Z28
Engine: 355 LT1
Transmission: T56
Axle/Gears: 3.42
Re: Big Block swap (work in progress)
Here's todays progress during the snow storm (I am working outside):
I plan on going back and supporting what I cut out of the frame rail, this is just a mock up.
#24
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Car: 86 TA, 91 B4C
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Transmission: 4L80 4000, T56
Axle/Gears: 4.30 M12, 23.42 10 bolt
Re: Big Block swap (work in progress)
LOL, what happened to smashing? Pretty funny, i am sure it was not an option on that part of the car.
#25
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Car: 1994 Z28
Engine: 355 LT1
Transmission: T56
Axle/Gears: 3.42
Re: Big Block swap (work in progress)
If I took the motor out I could have smashed that but I really felt like it would be easier to hack it apart and reinforce it later.
#26
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Car: 1992 Camaro RS
Engine: 8.0:1 454/Mild Hyd roller/Accel DFI
Transmission: WC T5
Axle/Gears: Stock 1992 open 7.5" 2.73 ratio
Re: Big Block swap (work in progress)
The small block stock radiator will work fine with either the single or TPI fan set up. I have several friends using them with 555 ci and bigger engines.
#27
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Car: 1994 Z28
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Axle/Gears: 3.42
Re: Big Block swap (work in progress)
Thanks that's comforting. Car is so close to being able to fire, need to find a ignition constant wire to wire to the ignition box, ground the block, and just bolt the driver's manifold on.
Spent the day relocating and removing gas lines that were on the driver's frame rail. Cut and capped the return line, and rerouted the supply and vent lines around the trans. It's turning out pretty promising, if it's warm out tomorrow I should defiantly get a test run in it.
Spent the day relocating and removing gas lines that were on the driver's frame rail. Cut and capped the return line, and rerouted the supply and vent lines around the trans. It's turning out pretty promising, if it's warm out tomorrow I should defiantly get a test run in it.
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