A lot of them that have been tweaked are faster than any production vette old or new.

 

If ya go with a 454... you might even get better gas mileage than a 350... I've seen numerous times where a big block will get bette gas mileage.. I even did a search awhile back and compared the '70 LS-6 which was in a chevelle (in a heavier car) and I compared it to an '70 LT-1 vette and If I am not mistaken the LS-6 got better mileage... Also I read a magazine online from '72 that talked about the gas mileage of the "new" '73s, It said that the LS4 got better gas mileage than the L82..

So my theory is go big displacement, with a mild cam and an overdrive... The only other thing I can think of would be to go with EFI!

 

Or perhaps you could go with diesel, one available here. Sounds interesting, I wonder what the performance is like with 48 mpg.
http://calgary.kijiji.ca/c-cars-vehi...QAdIdZ18003268

 

Yes I did consider doing exactly that to an 87 Corvette convertible that I owned since it was not dependable anyway but I even ( sit down guys) considered using a high performance 4 cylinder and driving to the cruises and laughing at all of the guys with the big block cars when the price of gas goes up. The only good thing about that car anyway was the body styling. But I think you should be arrested for doing it to a chrome bumper car.

 

A LS1 with a 6-speed should be good for mid-to-upper 20's MPG on the highway. I'll let you know when I finally get mine back on the road (don't hold your breath - it probably won't be this summer).



Rick B.

 

4.3s suck on gas. You wouldn't save much. Overdrive would be a better investment. That's if you drive it enough to make up 2-3gs in fuel.

 

DUDE!!! If money is that tight, then you do NOT even need a classic car as a toy. Or if your Vette is not just a toy but more like a DD, then you need another car.

A couple of years a go when gas was $1.00 per gallon cheaper, no one was ever complaining. Now, with the price approaching $3.00, you hear all this knd of stuff. Did you ever stop to think that with gas only $1.00 higher, it is only costing you $15.00 or less additonal money per fill up.

Again, if $15.00 per week is breaking your bank, you need to get out of the Classic Sportscar world.

 

I was looking for that link!!!!!1

Put a Diesel in .... GM is going to "Diesel" The new ones
http://www.youtube.com/watch?v=Lw9FTFlSsB0

 

What are you getting for mileage now? The 3/4 engine idea doesn't always work in practice.

Years ago, I pulled the '68 out of storage, and went to Bloomington. A belt broke and the others were needing replaced, but I found them after places had closed and we were on our way back. As such, we were stuck running about 55 and later 50 when the belts were slipping too much at 55, and the the water temp would go up.

Pulling in for gas, the '77 350 got 11 mpg, the '72 350 got almost 13, and I got about 14.5 with the 3.55 rear. When I ran the 3.08, I got about 19 with a 427.

So your 454 idea may be the way to go. However, there are good 454s and there are bad 454s. Avoid anything with the small port heads. The oval ports work best on the street for most people, but the '60s ovals are about twice the size of those in the '80s. My truck has those little ones, and it makes NO power. Lots of torque, but no power at all. And the mileage is around 8 normally and 10 on the highway with a tailwind.

I would not go with the mild cam and be picky about the heads. You want it to make power so it can basically loaf at highway speeds. At least the 390 hp cam and a little over that might do better, as long as you don't get radical.

Rear gears make a big difference. So an overdrive transmission would be a big plus on mileage.

And you have to add the cost of saving gas. Often you spend more to save than you actually save. How long does it take to save enough gas to pay for the typical $3000 5 speed installation? That is 1000 gallons of gas you could buy.

To save 1000 gallons, if the overdrive gets you 24 mpg

Now if you are running the typical 2500 miles per year as a collector, that is nearly 10 years to recoup for a 12 mpg car.

Put what engine in you want and enjoy.

 

"A friends" truck has the 4.3 V6 in it. In the standard cab, short box truck, it goes pretty well. It only gets 18 mpg max highway. If you would drive it how I would drive a sports car, you'd probably be looking at <15. But it would be interesting to see how the 4.3 acted in a vette because I assume it would be far lighter. But the truck would have different gearing ratios, so that might not be fair either.

Ok, it is my truck . . .

 

Tell that to the onwers of the 1953-1955 vettes that are worth over $150K.

 

I had an '85 Firebird with a 2.8 v6 and 5 speed.
Put in a 350 v8 and th350 tranny.
Lost 2 mpg. about 30 miles on a tank of gas.

 

I think much of your loss was the loss of the overdrive.

 

I am also voting for a GN 6.

 

As has been mentioned, I think you'd be better off with a modern EFI V8 engine and a 6-speed.

 

 

YA kool a Vette witha HiBred sticker on it!
Think this Forum should Black flag you for that thouight,
Ya I'm a newbe and just now wondering were I am

 

You know, GM built a lame V8 back in the 70's which displaced about the same as a six. It was a 262 cu in small block. With a decent set of heads and a 2 barrel, it could be pretty efficient and still looked the part when you opened the hood. With an overdrive transmission and not-too-wide tires, you could have the closest thing to an economy Vette. (But it still would not get as good a mileage as a stock C5)

 

I think Procast. racing said it pretty well...

I d say your best bet would probably be going with a ZZ454 cam... With an Edelbrock RPM performer manifold it produces around 510 HP - thats if the engines built like the ZZ454... The cam specs don't seem to be radical and I think it can be very fuel efficient for the HP that it produces!

 

You want some gas mileage and performance 3 2 bbls. I got 20 MPG with the old setup with a 4 speed and 3.55 gears and it would roast 295's for an 1/8 mile. You run on a 2 bbl untill you kick it. With an overdrive trans I could see 23 or 24 pretty easy.