dm567

Can you replace a big block engine on a 1973 corvette with a small block? (if your wondering why it would be to put in a fuel efficient modern engine)

Do they mount in the same place?

Will the radiator need to be replaced?

Will the suspension need to be changed? How?

Thanks

MelWff

read this thread

http://forums.corvetteforum.com/c3-t...-their-c3.html

brhulen

Yes - But if you're really interested in economy, why not a V6 or even a 4 cylinder?

Yes - As far as I know the Corvette has always been a front engine vehicle, but if you're really inventive I suppose you could reengineer the chassis and install the engine in the rear!

No/Yes - You won't need that heavy old radiator with a 4 cylinder. You could install one from a Mini Cooper.

No - But again there's no reason to hang onto those oversize tires that were designed with performance in mind. I'm thinking some nice 13 inch wheels and tires would do nicely! There's no sense in having more than you need.

All offered tongue in cheek! Did your C3 originally come with a BB and is it still running? If so, why don't you sell it and look for another C3 with the SB? Most of us aren't really that concerned with the gas mileage or we wouldn't have bought the doggone thing to begin with. Gas mileage/economy will probably be one of your lesser expenses when compared to restoration and maintenance.

keithinspace

I have to admit that I don't get this.

There are those that do the LS swaps, which is fine. Yes, they happen to be more economical, but it is generally done as a matter of customization and access to newer power-making technology. Not to make the Corvette into a econo-car.

With the amount of money involved in making the swap just to pick up a few MPG, I'd buy a Camry to commute and leave the BB in the Vette.

I get about 10 MPG with my small block around town, so simply making the swap to a small block isn't the answer. You need to get heavy into FI tuning and other things.

Consider adding a multi-port FI system on the BB? That would probably make a pretty big difference and not be so difficult a change...

Other things is a full roller inside the engine or lower gears out back. Swap the tranny to a 5 (or 6) speed. Something as silly as going with narrower tires makes a measureable difference.

That's the direction I would go if fuel economy was, for some reason, critical. You could probably get 20+ on the interstate if you make the right changes.

dm567

No i found a bb with a really great interior and great body. I just don't want a big block in it and was asking if there was any specific reason a small block crate engine with fuel injection and a matched 4 speed transmission with overdrive would fit easily. The engine/transmission combo I have in mind should at least provide some reasonable improvement in gas mileage over a BB with a 3 speed. BTW, are you aware that the new vettes get 26 on the highway, not 10 and i believe they have more horsepower than a 1970s bb? And they don't have 4 cylinders as you suggest. Not yet anyway!

qwank

Said no one, ever

Easy Mike

Yes. Bolt up depending on the type of smallblock you choose. LS engines will require a bit of engineering, but other folks have made the swap.

Yes.

No. A big block radiator will cool a small block.

No. The big block front springs are stiffer than stock smallblock springs due to the weight difference. You may want to install small blocks springs.

MelWff

Keep the BB and put in a 6 speed manual transmission and put in economy rear gears.

dm567

how about this engine, a crate ram jet 350, instead of the LS? Its made for 1975 and older GM cars.

http://store.chevroletperformance.co...-12499120--%3E

Why put a BB in when you can get this much power out a lighter FI SB?

From the description it sounds like this one will not require the modifications that an LS crate engine would. Is that correct?

What would be the best 4 speed automatic transmission with overdrive to pair with that will drop in without modifications? the one chevy performance sells? Keisler Engineering says theirs will drop in with their kit with no modifications. Its a A41 with overdrive.

TheSkunkWorks

As a devout member of the BB clan, and one who went in the opposite direction by upgrading my '78 with a 427 transplant, may I also suggest the OD manual transmission route. If you want FI, simply installl a FAST EZ EFI on your BB.

When comparing a SB and BB of equal peak power, IMCO it's worth noting that the BB will almost certainly put more torque under the curve (read, "produce higher average torque").

Yes, SB and BB C3's have different chassis tuning requirements, but I'd caution buying into the myth that BB sharks can't be setup to handle the twisty bits.

If you must, at least put the BB up in proper storage for the day when you decide (and you will for one reason or another) that it should go back in. My $.02.


TSW

dm567

Nothing against big blocks! They are part of american muscle car history and they increase the value of the car. I do hesitate paying more for a BB car and then taking it out. I also realize that if I do the modification I've probably ruined any future appreciation in value.

The perfect car for me would be a 1973, 1974, or 1975 with a blown small block so I can get it for less than the price of a running car. But I do want a clean body and interior.LOL

Easy Mike

Pricey, but should work. Where do you intend to put the computer?

dm567

Any suggestions on where to put the computer? Firewall? Under dash?

What about the transmission? The ones from chevy performance are electronically controlled and plug into the computer. Does anyone know anything about them? Are they direct replacements?

dom

24695bob

4 dollars a gallon...drive car 3000 miles a year
at 10 miles per gallon it will cost you 300 gallons or $1200 bucks...
at 25 mpg it will cost you $480 bucks that is significant BUT noway in hell would I do it especially for economic reasons..

Put in a 5 or 6 speed tranny in the thing out of a wrecked car from a junk yard..My oldest son has a 68 SS306 Chevelle he is running a 6 sp out of a wrecked Camero and gets very respectable millage yet still hears the sweet music the BB puts out...

Bob G

qwank

yup, and OD transmission is a win/win

shank0668

Don't tell me it's an original 454

briankeery

Now that's a combination with that BB sound that would put a smile on your face all summer long.

Why not start there, see how the numbers look, and if you really want to swap engines next year, at least you've already got the transmission and rear end figured out.

brent319

I would think seriously about how many miles a year you put on it and look at how long it would take to recoup the cost. Nothing on my car is original so I am not one of those "don't change anything" guys, but if i had a BB in there already and it runs well I would leave it (especially if it is original) and work on the stuff behind the engine. If you wound up with a BB and a six speed that sounds like a winning combo for milage, low end pull, sound, and that "bb 'vette" factor.
Then again, my wife will tell you I am an idiot if you ask her.
Probably even if you don't.

scottyp99

If you pay the premium for a nice big block car, just to tear it up and put a small block in it, you're an idiot. There are plenty of nice 'vettes out there that already have small block engines, buy one of them. If you don't know what to do with all the money you saved by doing this, just send it to me, I'll put it to good use.


Keep the shiny side up!
Scott

my 76 ray

Put the wrenches down and step away from the car.