Big block and trans swap question

[Sonny]

I have a 1970 Belvedere 318 and a 904. I'd like to swap the motor for a 383 or 440. This is a street car, not a race car. Will the BB bolt to the small block 904? Any issues or mods?

 

[wannadrag]

The sb and bb have different bolt patterns so they don't interchange.

 

[PurpleBeeper]

Your idea to put a big block in the Belvedere is very do-able, but it requires a whole bunch of parts & somewhat advanced mechanical knowledge OR a huge pile of cash. Another option to consider might be a 360 small block OR upgrade your 318 with some of the newer "magnum" 5.2L (318) parts. 273's (small) and 340's (expensive) also will bolt up. All of these small blocks are relatively easy bolt-in engines that can use your existing transmission/driveshaft/rear end, etc.

I forgot to ask you WHY you want to do this upgrade? I mean, I'd do it but I'm not the guy to be asking because I just want to go fast....really fast....then put nitrous on top of that.....and still trying to figure a way to convert it to alcohol so I can put a blower on it too.....it's like a disease.

 

[RT K_line]

I agree with purpleb about keeping the small block. You can get a 360 pretty inexpensively compared to a big block swap. You can build them from mild to wild.

 

[Bruzilla]

I forgot to ask you WHY you want to do this upgrade? I mean, I'd do it but I'm not the guy to be asking because I just want to go fast....really fast....then put nitrous on top of that.....and still trying to figure a way to convert it to alcohol so I can put a blower on it too.....it's like a disease.

I can tell you why I've always done it. I got tired of having people ask me "What 'ya got in it?" and when I tell them a small block they say "I'll bet you wish it had a 440!" Hearing that all the time is bad, but realizing they are 100% correct is worse. To me, and this is personal opinion, but having a small block in a Mopar muscle car is like getting a kiss from your sister.

You will need to get a Schumacher BCEB kit too make the swap, or get a set of Big Block mounts.

My suggestion for all folks doing this is don't waste a ton of money buying parts. Look on Craigslist for a well-worn but running/driving 440 C body that someone is looking to get rid of (there are a lot of them here in Florida), buy it, take all the parts you need off, then take parts that others want off and sell them. then scrap the rest. Play your cards right and you can make the swap quickly and for free, and even make money off the effort.

 

[PurpleBeeper]

I hear you bruzilla. Sonny isn't trying to run mid-9's in the quarter.... and keeping in mind the "macho-cool-factor" you're talking about....what about a 360 six-pack?....with an air grabber hood?

To Sonny --> Seriously, WHY? Bragging rights? Cool Factor? 318 getting worn out and figured "what the heck"? Needing to tow a boat/trailer? Also, how much money do you have to spend on it? And how long can you go without driving it while you do the swap?

 

[Bruzilla]

I hear you bruzilla. Sonny isn't trying to run mid-9's in the quarter.... and keeping in mind the "macho-cool-factor" you're talking about....what about a 360 six-pack?....with an air grabber hood?

Your question reminds me of an event I went to in 1988 or 1989. There was a guy there with a Camaro with a 350 that had two Superchargers on it. I had to give it to him, it was impressive as all get out, and made over 1,200 HP. His car was next to mine, and folks kept coming by and they would see those Superchargers on the mouse and say "I'll bet you wish those were on a 454!" Then they would come over to our Roadrunner and marvel that it had a 440. We kept hearing "Did they really put 440s in these cars?" That dude's Camaro made about five times the HP our 440 did, but our 440 got the attention.

All this taught me the lesson that a small block, no matter what you do to it, will always be a small block. You can stick a six pack on a 360, and it's always going to be just a 360. Meanwhile, you can stick a six pack on a 440 RV engine, and that's a "440 Six Pack!!!". It doesn't matter if it runs like poop, it's still got panache just for having the most cubic inches. That's just the reality of the hobby. If you watch Bar Rescue on Spike, Jon Taffer would call it "perceived value."

 

[Billccm]

I agree with the 'perceived value' comment. The common question with B Bodys is "....383, or 440?". Having said that, there is 'real' value with keeping your car as is, especially when looking at budgets vs fun factor.

 

[Mark1972]

Since getting my car on the road a few weeks ago, I must have had a dozen people pull up beside me and ask if it's a 383 or a 440. Always with a big smile. I smile back and tell them it's a 318. The smile turns sympathetic like they feel sorry for me. I always said I would never care. I was wrong. I bought a 1970 383 and it's on the engine stand now. Peer pressure sucks, lol.

 

[Bobby Sixkiller]

You will need a 727 tranny for a big block. A drive shaft for a 727. Motor mounts. Radiator. The rest depends on how complete your 383 is. Pan. Exhaust manifolds or headers. Brackets. Etc. Completely doable. Not real hard.

 

[Mark1972]

With the cruising season almost wrapped up around here, I have all winter to get the other parts together. Thanks for the list. I'm on the fence about adding bigger torsion bars to that as well. I was given the advice to add a rear sway bar too. First time anyone had ever mentioned that. Either way, considering winter around here is like 6 months long, I've got time to figure stuff out while the car is in its warm winter storage. Cheers.

 

[Curiousyellow71]

On our 72 satellite we added a rear sway bar off a 78 dodge magnum and it made a huge difference on the handling. We did a little welding and made it fit. It was a 318..now 440...the next engine for it is in at the machine shop right now. It's a 541 b engine and when you pop the hood it will look like a stock 400 4 barrel with a/c.
Imo....Big blocks...are fun to work on. I just like the design better. I have worked on all the different brands..but a BB mopar I enjoy...others...not so much. But, I am not discouraging anyone who wants a small block.or feels like it's a more economical choice. But to me...go as big as you can afford....you will not regret it.

 

[Cranky]

I like the Big Blocks better too..... And whenever someone asked me what I was running the reply was usually a slant six no matter what was under the hood!

 

[Bobby Sixkiller]

The big block design is great. From the block around the crank to the external pump. To the distributor in the front and the dry intake. The wedge head. They are great engines. Reliable. Tough. Easy horsepower. After all these years I’m still driving the same engine I built in high school. Just in a different wrapper

 

[Curiousyellow71]

A BB built right will surprise you on the mpg as well.

 

[Cranky]

A BB built right will surprise you on the mpg as well.

Guess I did all of mine wrong....wait, my right foot is shaped like a brick!

 

[Curiousyellow71]

Funny Cranky... BB's are also excellent for GPM...gallons per mile...preferably 1/4 mile at time.

Guess I did all of mine wrong....wait, my right foot is shaped like a brick! [/QUOTE

 

[Cranky]

Funny Cranky... BB's are also excellent for GPM...gallons per mile...preferably 1/4 mile at time.

My first race only car was a 68 road runner that ran 10.68 with a tunnel ram and two 750's on top, it would make 1 pass on a gallon and run out on the return road and then coast a couple hundred feet and almost make it into my pit area. It really slowed down making a turn....dang spool really killed mileage lol

 

[wyrmrider]

rear sways from Cordoba or similar really work
largest front torsion bars possible with today's wide radial tires
big front sway
can make a b body corner like a sports car

 

[HEMI-ITIS]

Your idea to put a big block in the Belvedere is very do-able, but it requires a whole bunch of parts & somewhat advanced mechanical knowledge OR a huge pile of cash. Another option to consider might be a 360 small block OR upgrade your 318 with some of the newer "magnum" 5.2L (318) parts. 273's (small) and 340's (expensive) also will bolt up. All of these small blocks are relatively easy bolt-in engines that can use your existing transmission/driveshaft/rear end, etc.

I forgot to ask you WHY you want to do this upgrade? I mean, I'd do it but I'm not the guy to be asking because I just want to go fast....really fast....then put nitrous on top of that.....and still trying to figure a way to convert it to alcohol so I can put a blower on it too.....it's like a disease.

Don't need to burn alcohol to be blown,,,just drink it
I burn pump gas for street driving