BBC Conversion Question:
Burning Brakes
Joined: Oct 2009
Posts: 782
Likes: 1
From: Magic Valley ID
I agree. there should be some sticky made for this.
I have decided to switch gears, so to speak with my 76 project car. I was going to put the TPI engine in there, but after considering the 454 option, I have sprung for 2 454 engines that I found locally. Come to find out that both blocks have the same casting number, but 1 is from an 85 Chevy 1-ton truck, comes with a shorter pan, rebuilt with 30k miles on it, a mild RV cam, and bored .060 over. It comes married to a rebuilt TH350, for $500. It will need some accessories, pulley, brackets, etc....but should be a good candidate for the 76.
The other is from a mid 70's truck, and has all pulleys, brackets, etc...but of course the alternator is on the passenger side. I trade a 74 350 Chevy truck motor straight across for it. It has 72K miles on it.
Neither engines leak, burn oil, or have any issues, and ironically both had been installed in Novas. If the first 454 swap goes well, then I will consider pulling the 383 stroker in my 80 and putting it in there.
As my buddy pointed out today......there's no replacement for displacement!!
Deja
I have decided to switch gears, so to speak with my 76 project car. I was going to put the TPI engine in there, but after considering the 454 option, I have sprung for 2 454 engines that I found locally. Come to find out that both blocks have the same casting number, but 1 is from an 85 Chevy 1-ton truck, comes with a shorter pan, rebuilt with 30k miles on it, a mild RV cam, and bored .060 over. It comes married to a rebuilt TH350, for $500. It will need some accessories, pulley, brackets, etc....but should be a good candidate for the 76.
The other is from a mid 70's truck, and has all pulleys, brackets, etc...but of course the alternator is on the passenger side. I trade a 74 350 Chevy truck motor straight across for it. It has 72K miles on it.
Neither engines leak, burn oil, or have any issues, and ironically both had been installed in Novas. If the first 454 swap goes well, then I will consider pulling the 383 stroker in my 80 and putting it in there.
As my buddy pointed out today......there's no replacement for displacement!!
Deja
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Just for info- earlier in this thread there was mention of the tall deck 366/427 engines. They were used in the 50-60-70 series trucks only. GM never used those tall blocks in pickups. And very few of the 366's were in the 50 series- they were mostly 327/350.
Melting Slicks
Joined: Nov 2003
Posts: 2,362
Likes: 1
From: San Antonio TX
Let me see if I get this right a sticky to replace a SB Chevy With a BB Chevy that will accept either one as they came from the factory hmmmmmmmm.
The problem is that there are the simple ways to do it or what would be called the minimal way all the way to expensive and lots in-between.
Look at the Site Paranoid has and it will give some good info along with the web page I posted also has some good info.
But I will give my simple opinion on a few things that should be addressed in such a swap.
One Depending on where you live one should think about an update as far as the cooling capacity of the radiator as the Big Block will require more than a SB. You can go with a stock set up for a Big Block or you can go aftermarket from such people as our own DeWitt with duel spal fans or a universal type of aluminum radiator with a Mark VIII fan or Taurus fan of which you can find that information here on the forum as well.
Second is the brackets that are needed to do the change over. You can go with the factory type of parts to do this from people like http://www.corvette-paragon.com/ though not cheap it is less than the more fancy ones such as those offered by people like March even though they are nice looking and functional. It all depends on what you like and how much you would wish to spend.
As for the front springs as said if you have aluminum heads and intake then you are close to the weight of a stock SB. But if the Big Block is all Iron then you should look into a good set of springs from the good people here such as VBP.
As far as the Hood goes you can get away with your stock Hood but you will have to give up a bit of performance to do so as it would require the use of a very low intake manifold such as the Edelbrock Torquer 2. If you wish to use a better intake such as the Edelbrock Performer then an L-88 or some type of High Rise hood is in order to give good clearance.
If you have a standard shift then a new flywheel will be needed for the Big Block along with a new clutch and pressure plate and throw out bearing. Since you are there this is the time to do it.
If an Auto then all you would need is the correct flex plate.
As for exhaust you can get a stock set of Iron exhaust manifolds or headers or side pipes as this is a personal choice.
These things are what is needed but if you build up the Big Block for higher HP and TQ numbers further changes maybe needed in the driveline to survive over any length of time.
With all that said I do like the Big Block for the street since they will give a tremendous amount of TQ down low and that is what moves the weight of the car. Also with larger cubic inches you can run less compression to accept today's bad gas and still give good performance.
On the flip side of this is the fact that today you can build a good streetable 383 or 406 that may not give the off the bottom end TQ of a Big Block but will be no slouch and be able to retain all of the parts you have now except I would still upgrade the cooling system. Also you will not loose any handling capability by staying with the SB style of engine.
So I offer this. If you can by all means drive a Big Block Corvette and then drive a good Small Block Corvette and you will feel how each type of car will handle. Then decide which way you wish to go. As with anything else it is a personal preference.
Some people love the Big Block car others hate it. Even though many like the thought of a Big Block till they drive one lol. Given the same car with just an engine change of comparable HP ratings between a SB and a Big Block they will behave completely different.
The problem is that there are the simple ways to do it or what would be called the minimal way all the way to expensive and lots in-between.
Look at the Site Paranoid has and it will give some good info along with the web page I posted also has some good info.
But I will give my simple opinion on a few things that should be addressed in such a swap.
One Depending on where you live one should think about an update as far as the cooling capacity of the radiator as the Big Block will require more than a SB. You can go with a stock set up for a Big Block or you can go aftermarket from such people as our own DeWitt with duel spal fans or a universal type of aluminum radiator with a Mark VIII fan or Taurus fan of which you can find that information here on the forum as well.
Second is the brackets that are needed to do the change over. You can go with the factory type of parts to do this from people like http://www.corvette-paragon.com/ though not cheap it is less than the more fancy ones such as those offered by people like March even though they are nice looking and functional. It all depends on what you like and how much you would wish to spend.
As for the front springs as said if you have aluminum heads and intake then you are close to the weight of a stock SB. But if the Big Block is all Iron then you should look into a good set of springs from the good people here such as VBP.
As far as the Hood goes you can get away with your stock Hood but you will have to give up a bit of performance to do so as it would require the use of a very low intake manifold such as the Edelbrock Torquer 2. If you wish to use a better intake such as the Edelbrock Performer then an L-88 or some type of High Rise hood is in order to give good clearance.
If you have a standard shift then a new flywheel will be needed for the Big Block along with a new clutch and pressure plate and throw out bearing. Since you are there this is the time to do it.
If an Auto then all you would need is the correct flex plate.
As for exhaust you can get a stock set of Iron exhaust manifolds or headers or side pipes as this is a personal choice.
These things are what is needed but if you build up the Big Block for higher HP and TQ numbers further changes maybe needed in the driveline to survive over any length of time.
With all that said I do like the Big Block for the street since they will give a tremendous amount of TQ down low and that is what moves the weight of the car. Also with larger cubic inches you can run less compression to accept today's bad gas and still give good performance.
On the flip side of this is the fact that today you can build a good streetable 383 or 406 that may not give the off the bottom end TQ of a Big Block but will be no slouch and be able to retain all of the parts you have now except I would still upgrade the cooling system. Also you will not loose any handling capability by staying with the SB style of engine.
So I offer this. If you can by all means drive a Big Block Corvette and then drive a good Small Block Corvette and you will feel how each type of car will handle. Then decide which way you wish to go. As with anything else it is a personal preference.
Some people love the Big Block car others hate it. Even though many like the thought of a Big Block till they drive one lol. Given the same car with just an engine change of comparable HP ratings between a SB and a Big Block they will behave completely different.
Last edited by SHAKERATTLEROLL; Feb 26, 2010 at 01:26 AM.
Burning Brakes
Joined: Oct 2009
Posts: 782
Likes: 1
From: Magic Valley ID
Let me see if I get this right a sticky to replace a SB Chevy With a BB Chevy that will accept either one as they came from the factory hmmmmmmmm.
The problem is that there are the simple ways to do it or what would be called the minimal way all the way to expensive and lots in-between.
Look at the Site Paranoid has and it will give some good info along with the web page I posted also has some good info.
But I will give my simple opinion on a few things that should be addressed in such a swap.
One Depending on where you live one should think about an update as far as the cooling capacity of the radiator as the Big Block will require more than a SB. You can go with a stock set up for a Big Block or you can go aftermarket from such people as our own DeWitt with duel spal fans or a universal type of aluminum radiator with a Mark VIII fan or Taurus fan of which you can find that information here on the forum as well.
Second is the brackets that are needed to do the change over. You can go with the factory type of parts to do this from people like http://www.corvette-paragon.com/ though not cheap it is less than the more fancy ones such as those offered by people like March even though they are nice looking and functional. It all depends on what you like and how much you would wish to spend.
As for the front springs as said if you have aluminum heads and intake then you are close to the weight of a stock SB. But if the Big Block is all Iron then you should look into a good set of springs from the good people here such as VBP.
As far as the Hood goes you can get away with your stock Hood but you will have to give up a bit of performance to do so as it would require the use of a very low intake manifold such as the Edelbrock Torquer 2. If you wish to use a better intake such as the Edelbrock Performer then an L-88 or some type of High Rise hood is in order to give good clearance.
If you have a standard shift then a new flywheel will be needed for the Big Block along with a new clutch and pressure plate and throw out bearing. Since you are there this is the time to do it.
If an Auto then all you would need is the correct flex plate.
As for exhaust you can get a stock set of Iron exhaust manifolds or headers or side pipes as this is a personal choice.
These things are what is needed but if you build up the Big Block for higher HP and TQ numbers further changes maybe needed in the driveline to survive over any length of time.
With all that said I do like the Big Block for the street since they will give a tremendous amount of TQ down low and that is what moves the weight of the car. Also with larger cubic inches you can run less compression to accept today's bad gas and still give good performance.
On the flip side of this is the fact that today you can build a good streetable 383 or 406 that may not give the off the bottom end TQ of a Big Block but will be no slouch and be able to retain all of the parts you have now except I would still upgrade the cooling system. Also you will not loose any handling capability by staying with the SB style of engine.
So I offer this. If you can by all means drive a Big Block Corvette and then drive a good Small Block Corvette and you will feel how each type of car will handle. Then decide which way you wish to go. As with anything else it is a personal preference.
The problem is that there are the simple ways to do it or what would be called the minimal way all the way to expensive and lots in-between.
Look at the Site Paranoid has and it will give some good info along with the web page I posted also has some good info.
But I will give my simple opinion on a few things that should be addressed in such a swap.
One Depending on where you live one should think about an update as far as the cooling capacity of the radiator as the Big Block will require more than a SB. You can go with a stock set up for a Big Block or you can go aftermarket from such people as our own DeWitt with duel spal fans or a universal type of aluminum radiator with a Mark VIII fan or Taurus fan of which you can find that information here on the forum as well.
Second is the brackets that are needed to do the change over. You can go with the factory type of parts to do this from people like http://www.corvette-paragon.com/ though not cheap it is less than the more fancy ones such as those offered by people like March even though they are nice looking and functional. It all depends on what you like and how much you would wish to spend.
As for the front springs as said if you have aluminum heads and intake then you are close to the weight of a stock SB. But if the Big Block is all Iron then you should look into a good set of springs from the good people here such as VBP.
As far as the Hood goes you can get away with your stock Hood but you will have to give up a bit of performance to do so as it would require the use of a very low intake manifold such as the Edelbrock Torquer 2. If you wish to use a better intake such as the Edelbrock Performer then an L-88 or some type of High Rise hood is in order to give good clearance.
If you have a standard shift then a new flywheel will be needed for the Big Block along with a new clutch and pressure plate and throw out bearing. Since you are there this is the time to do it.
If an Auto then all you would need is the correct flex plate.
As for exhaust you can get a stock set of Iron exhaust manifolds or headers or side pipes as this is a personal choice.
These things are what is needed but if you build up the Big Block for higher HP and TQ numbers further changes maybe needed in the driveline to survive over any length of time.
With all that said I do like the Big Block for the street since they will give a tremendous amount of TQ down low and that is what moves the weight of the car. Also with larger cubic inches you can run less compression to accept today's bad gas and still give good performance.
On the flip side of this is the fact that today you can build a good streetable 383 or 406 that may not give the off the bottom end TQ of a Big Block but will be no slouch and be able to retain all of the parts you have now except I would still upgrade the cooling system. Also you will not loose any handling capability by staying with the SB style of engine.
So I offer this. If you can by all means drive a Big Block Corvette and then drive a good Small Block Corvette and you will feel how each type of car will handle. Then decide which way you wish to go. As with anything else it is a personal preference.
I am lucky enough to have 2 Vettes....my 80 that does have a 383 stroker motor, and it gets up and scoots! The other is my 76 that I am actually building for my wife. I talked her out of the Jeep Wrangler, and into the Corvette......I KNEW I had a good woman!
And she is actually wanting me to put the 454 in there, which was a little bit of a surprise. I had originally thought of pulling the 383 and putting that in hers, but MAN, she was all sorts of bummed out when I told her that.....so I will concede to the bigger engine in hers. I'm just afraid that when I get all done with it, that I will like the performance in hers better than mine!! She even wants to race me when it's all done....so that should be fun!! I have never driven anything with a BB in it, so this should be a real eye opener. I've already warned my bride that the rear end will now be REALLLLLLLY swap-happy...so here's to hoping that she doesn't get all wild and crazy and swap ends into a tree or something.
Deja
Melting Slicks
Joined: Nov 2003
Posts: 2,362
Likes: 1
From: San Antonio TX
Deja you are very welcome there are many people here that have done the swap. So while you are doing it if you have any questions please ask and I am sure someone will step up to the plate to help.
Le Mans Master
Joined: Aug 2003
Posts: 7,720
Likes: 12
From: Chattanooga TN
I see....so let me ask this......would a complete 454 with all accessories and the alternator already mounted on the driver's side, drop in and fit....I mean using the existing 454 pullies ad cast exhaust manifolds? Or will the pullies hit somewhere? And would an 85 block be a tall deck motor? I hear that there are clearance issues with a tall deck motor, but I don't know how you can tell short from tall decks.
The front suspension has to be rebuilt anyways, so the upgrade to BB springs is no biggie.
And what displacement is a 454 that has been bored .060 over
Deja
The front suspension has to be rebuilt anyways, so the upgrade to BB springs is no biggie.
And what displacement is a 454 that has been bored .060 over
Deja
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
2027 Corvette vs The World: Every Model vs Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
10 Things C8 Corvette Owners Hate (But Won't Tell You)
Joe Kucinski
10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!
Brett Foote
Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)
Joe Kucinski
Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!
Michael S. Palmer
5 Reasons Bad Drivers Crash & 5 Ways to Avoid a Costly Mistake!
Joe Kucinski
Burning Brakes
Joined: May 2008
Posts: 1,116
Likes: 5
From: Middleburg Florida
There is however the serpentine conversion that solves the issue of brackets and such. And with the serpentine set ups you have to use the long style pump, but it must also be a reverse flow design. The serpentine brackets accomodate the shorter R4 style AC compressores too, and you use electric fans which require less space. You're going to want to upgrade your current radiator for the big block anyway so it makes sense to go with the fans too.
The bottom line is to really plan your project and gather information as you are here. Gather the information and parts, realizing there are always going to be surprises, espsecially with conversions. For instance, when I put the big block in my car, I thought I had it all covered. Went to all the way to connecting the throttle cable and cruise control rod and they were short!!!! Not the cable, but the bracket off the small block had to be lengthend almost 2". Same with the cruise control rod. Just one example of many small, necessary issues that will have to be addressed in a conversion like this. But it can be done, it's a blast to drive, it's fun to see peoples faces when they see under the hood, and doesn't have to break the bank...
The bottom line is to really plan your project and gather information as you are here. Gather the information and parts, realizing there are always going to be surprises, espsecially with conversions. For instance, when I put the big block in my car, I thought I had it all covered. Went to all the way to connecting the throttle cable and cruise control rod and they were short!!!! Not the cable, but the bracket off the small block had to be lengthend almost 2". Same with the cruise control rod. Just one example of many small, necessary issues that will have to be addressed in a conversion like this. But it can be done, it's a blast to drive, it's fun to see peoples faces when they see under the hood, and doesn't have to break the bank...
Heel & Toe
Joined: Mar 2010
Posts: 20
Likes: 0
What is a Z Bar? I heard that it may be different on some years from a small block to big block. I have a 74 Automatic L48 (350) and want to put in a 454. Is it different on this car and if so can it be changed out?
Burning Brakes
Joined: Oct 2009
Posts: 782
Likes: 1
From: Magic Valley ID
Man....getting brackets for this thing is the most aggravating part of the whole ordeal. The intake that I have is a 1978 BB intake....not sure what it's out of, but it is a dual plane, stock, spreadbore intake, and the cab mounting surface is VERY low. Perhaps it's out of a Nova or Chevelle of that year...I dunno.
The water pump was purchased locally, and is out of a late 60's Chevelle (reman with a 3/yr warranty).
I did opt to go with a Gilmer belt drive, and the nice thing about that, is that the crank pulley is an underdrive type...so it would not hit the crank, even if it was a long water pump.
But as mentioned previously, the brackets are the real pain. And I'm not sure why everyone is so dead set on having the alternator on the driver's side? Makes more sense to me, that if you don't have an AC compressor to contend with, it would be easier and make LOTS more room to have it mounted on the passenger side. You might have to run a longer wire for the altenator, but it frees up a lot more room IMO. Another option is a power steering pump that uses a remote reservior. It just seems like it would be a real PITA to add p/s fluid with the alternator and p/s pump mounted so close together....far worse than even a sbc with the same arrangement.
It would just be nice if someone out there made a complete conversion kit, just to take out te guesswork and hassle of rounding up all of the parts and pieces. I think someone could make a killing doing that!
Deja
The water pump was purchased locally, and is out of a late 60's Chevelle (reman with a 3/yr warranty).
I did opt to go with a Gilmer belt drive, and the nice thing about that, is that the crank pulley is an underdrive type...so it would not hit the crank, even if it was a long water pump.
But as mentioned previously, the brackets are the real pain. And I'm not sure why everyone is so dead set on having the alternator on the driver's side? Makes more sense to me, that if you don't have an AC compressor to contend with, it would be easier and make LOTS more room to have it mounted on the passenger side. You might have to run a longer wire for the altenator, but it frees up a lot more room IMO. Another option is a power steering pump that uses a remote reservior. It just seems like it would be a real PITA to add p/s fluid with the alternator and p/s pump mounted so close together....far worse than even a sbc with the same arrangement.
It would just be nice if someone out there made a complete conversion kit, just to take out te guesswork and hassle of rounding up all of the parts and pieces. I think someone could make a killing doing that!
Deja
Burning Brakes
Joined: Mar 2010
Posts: 1,076
Likes: 22
From: KY
I changed my '68 from a SB to BB. I used the GM brackets and pulleys for alt and P/S. It's a non A/C car. I also changed it to a BB, or A/C, radiator support and a DeWitt's radiator.
Last edited by 68-427Rich; Mar 9, 2010 at 08:04 PM. Reason: Spelling, spelling, spelling
Melting Slicks
Joined: Jul 2009
Posts: 2,091
Likes: 40
You have had some WISE advise....from converters of SB to BB...and they are right , it will be expensive one way or the other.. and alot more headaches than you dreamed.. HAVE you considered Maybe , just finding an actual BB car with a running engine and fixing it up might be easier in the long run. SO you could concentrate the improvements on rebuilding the engine the way you like. Unless you just love a big challenge.
JUst food for thought.
Good luck my friend
JUst food for thought.
Good luck my friend
Burning Brakes
Joined: Oct 2009
Posts: 782
Likes: 1
From: Magic Valley ID
You have had some WISE advise....from converters of SB to BB...and they are right , it will be expensive one way or the other.. and alot more headaches than you dreamed.. HAVE you considered Maybe , just finding an actual BB car with a running engine and fixing it up might be easier in the long run. SO you could concentrate the improvements on rebuilding the engine the way you like. Unless you just love a big challenge.
JUst food for thought.
Good luck my friend
JUst food for thought.
Good luck my friend
Deja
