Yellow79

well as the topic states im looking at converting my SB '79 to accept a certain 454 that was offered to me. i must say that i value the handling potential of the car quite a bit, so that does worry me. the motor is a pretty trick unit, its using the LS-7 block from a '70 chevelle and some very potent heads, if it went into my car it would be pushing somewhere around the 650 horse mark. and so my concerns, in short are:
1. reliability of the swap, will it be less reliable than a car that came with a BB originally? with a better radiator and an electric pump can i keep the car cool?
2. how badly the handling is affected, i value handling quite a bit and if it deadens the steering response and feel/grip considerably, id like to know. also if there is any kind of suspension kit that might be able to make up for the extra few hundred pounds. if someone out there who has done this conversion would speak up and tell me how much and what way it changed the feel of the car that would be great!
3. what kind of work does it take to make the tranny live under these power conditions? would this null out my future plans of a T-56 install, or could the T-56 still handle that power?
4. and last but not least what the job entails. i have no idea whatsoever what it would take. what i know are the obvious things- larger exhaust / more hood clearance/ better cooling. past that i dont know jack :conehead

any help is appreciated! thanks!

goofygrin

um

your gas mileage goes down?

you can drive in the winter without heat?

you get all the chicks?

I don't get this word "downside" :D :jester

Corey_68

Breaking parts more often. :eek:

Hey, what do you expect when have a motor that makes that much torque. :D

Fevre

From what I have read it sounds like only the cost and a slight decrease in handling but I don't think I have seen one person post that they regreted doing so it most be worth it.

flynhi

In addition to the long block with carb,
I think you will need:
alum radiator
Possibly radiator frame
motor mounts
brackets for alternator, PS pump, AC compressor
flywheel
clutch
larger front sway bar
add rear sway bar
higher rate front springs
HD u joints on drive shaft and half shafts

beware of possible interference between driver side valve cover and PB booster.

I've driven a BB C3 with loose suspension and it was scary. You should also replace all suspension bushings, ball joints and tie rod ends as well as rag joint and idler arm

Jughead

Only one drawback to a BB swap, you'll no longer have a savings account or pension. :lol:

Chuck Harmon

Generally, the more radical the engine, the less the reliability and civility. Regarding the handling, I don't think it needs to be any different. My big block is within a very few pounds of the original small block. Aluminum heads, intake, water pump, headers, and radiator brought the weight way down. It is also true that you could do the same for a small block and make it even lighter. Another truism is that it is easier to drive a car with less power than with more. Required skill levels go up exponentially with power to weight ratios, at least to get the most out of the combination.

Just like remodeling a house, there is always more hassle and expense than you expect with a transplant.

A BB will make power more easily than a small block. I could make mine a kitty cat with silky smooth power coupled with massive torque levels. But that is not what I had in mind. My biggest frustration with a BB is that you don't have as much room to work around the engine as with the small block. Once my scraped knuckles heal, I always re-affirm my choice for the BB.

Chuck

73jst4fun

I think all the pros and cons of engine swapping have been covered. A big block can be made very light but at what expense...reliability certainly is an issue, gas mileage could be a concern but not when you own a vette :lolg: the heat is an issue, some of my friends own big blocks and they all are a bear in the summer, and they fill up the engine compartment and are a pain in the A@#$% to work on :( I'm sure you'll make the right choice for you to enjoy :seeya

jpatrick636

Setting off all the car alarms as you drive by in the parking lot.

Wait a minute!

Now that I think about it, thats kinda fun.

R 73 454

:mad Be prepared for HEAT, do everything possible for an efficient cooling system. My 73 454 actually runs pretty cool for a big block, but once I hit the slow crawl "cruising parade" mode, I'm anxiously watching the temp gauge climb into the danger zone. REAL tough on hot restarts, that starter turns embarassingly slow! :cry

stinky

You can still go with a T56..as long as its the Viper/GM aftermarket one! Or consider the new Tremec 5spd said to handle 600 ft lbs of torque; either will suffice needless to say.

markdtn

The engine you describe doesn't sound like aluminum heads, so you will have more weight on the front end. The Vette is close to 50/50 weight distribution with a SB depending on options. Me, I would stay with the SB-but that's just me.

norvalwilhelm

what are the downsides to a BB swap?

That stupid grin that is permanently attached to your face whenever you drive the vet. Everything thinks you are simple. :lol: :lol: :lol:

Seriously I get 15 mpg with my big block and with a proper rad and fans overheating is not a problem.
As for motor mounts, ignition and transmission they are the same as a small block. A little creative fabricating powersteering and alternator mounts can be built.
There is nothing like the torque of a big block.


[Modified by norvalwilhelm, 8:12 AM 2/26/2004]

Yellow79

wow! thanks for all of the replies!
i can tell it will cost a bit to swap the motor, i had planned on about a two thousand dollar fund that i would need to complete it. i still have plenty of time as i cant afford it until the summer but i need to research right now, if i do decide to perform the swap.

as far as weight, that is the main thing i am worried about. the added weight doesnt bother me its WHERE the weight is- over the front tires....and i do value my handling. along with all the other drivetrain parts in my car, and the paint, etc etc. the only reason i am even considering it is because its a very good deal on a pretty trick motor. hes asking 3000 for the long block, but it needs a rebuild to run on street gas. it is essentially a built up LS-7 -all steel 454, bored .030 over with a lot of premium grade parts. 292 (?) head castings i think, if i got the numbers right. im told they are very very hard to find nowadays and very potent once you rework them. he dyno'd out the car once at a chassis dyno and the numbers were right around 660 RWHP and 590 RWTQ. so as far as we could figure it was running about 750-800 horse and somewhere around 700 ft-lbs of torque. ive been in the car before he pulled the motor and i can verify that. with six people in the chevelle, he was literally just toying with a friend of mine who has about 450-500 horse at the crank in his '68 BB camaro. every time the camaro got close to the rear fenderwells and i thought he was finally going to overtake us, hed just peg it again and walk the camaro. by about three car lengths in what would equal two city blocks. when we finally stopped, my buddy jumped out of his car and ran over to demand what was in the chevelle. he got offered a pretty nice sum of money for the chevelle, but the buyer was not interested in the motor. as it sits right now, its running about a 14.5:1 compression. ive thought about just leaving it as it sits because its such a dynamite package, but i dont think it would travel very well on $4 a gallon fuel. on top of that, i dont have enough experience with that kind of power to trust myself with it. he tells me we can drop it down to a straight pump gas managable compression level and still run about 650 horse. im going out tonight to look at it and take some pictures. if this pulls through, is anyone interested in a decent collection of parts for a 406 SBC? :lol:




[Modified by Yellow79, 3:48 AM 2/27/2004]

GDaina

Yup....and when you get pulled over for a tickey, the Occifer will look at that grin of yours, and write you up for another citation, and after that, that grin is still there, he will continue to issue another citation...when it stops is when the Occifer's wrist fatigues from writing, but you still have that never ending grin.... :cheers:

Corey_68

To those who say a Big Block handles like crap, just rember a '68 L88 convertible won LeMans in ('72 or '73). :D

Biggus Blockus

Those who say a BB handles like crap never drove a big block Corvette, or they are envious.

In my 65, the Big Block actually makes the weight distribution closer to 50/50 (per road & track circa 1965). I think the handling problems come from lack of traction at the rear wheels!

A big block will put a perma-grin on your face. It will win you friends and destroy your enemies.

No one with a Big Block ever ponders the question:

"if it only had a small block...."

Good luck with your decision.

Corvette_fetish

:eek: That's double what I'm getting with my 350 right now!

Fevre

I am shooting to make you bb guys say:

"if only my bb ran like that guy's sb" :mad

:jester

big632

FEVRE DREAM ON.