since im gonna get **** for gas mileage with a 396 as some of you said, i was wondering if its better to just go 454 and get that added power. ive checked the internet and see that the 396 will get anywhere from 10 - 17 mpg, and that the 454 gets from 2 - 15. anyone from here have any numbers?

I am certain some of the engines getting low mileage are entertainment pieces.
I get lots of smiles from my 454 and bad MPG.
Consider a 396 as 4/5 of a 454 and decide from there.
If mpg is your desire, get a 283. If you want power, a 396 will do. If you wanna go fast, get a 454. If you want to go really fast 496. Stupid fast 540 or larger

haha i cant get anything bigger than a 454, i plan on spending just over 1 grand on the 396 that came with my chevelle, or spend 1 grand and get a complete engine that ran a year ago, turns over fine, and im leaning towards that. but with these gas prices, the 454's are cheaper than the 396's on craigslist. lol

Im pretty sure nobody buys a chevelle for gas mileage, buy the most hp you can afford and screeeew it! lol

yea i didnt buy it for gas mileage either, but im only 17 and i was hoping to have it as my daily driver. but now im thinkin screw the the system, get a 454, drive it on weekends or whatever.

We don't drive our Chevelles for gas mileage anyway. 454

If I were you, I would stay with the 396. That is my opinion. However I agree with what Kettbo said.

You can build a VERY mild 454 that will put out more h.p. and torque down low in the rpm range where you need it than a slightly more radical 396. And probably get better mileage too boot. This being because you won't have to flog it so much, just as long as you can control yourself! I know, it's hard. There should be a support group..... naaahhhh! Not that a 396 is weak, it isn't, but for reliability sake as an almost daily driver I would keep the rpm's low and get a smooth idling R.V. style cam. This is where the cubic inches come into play.

Freddy, whats your reasoning on staying with the 396.

and Matt, i was thinking about one of those thumpr cams, would that be too much for a 396 or 454 thats gonna be an almost daily driver?

One other point of view is that a 396 has somewhat of a cool factor, since it was the original engine for an SS396. For my Saturday night cruise in car, a 396 or 327 would be just fine. It just happened to come with a 350 in it.

Yep, 396 for the coolness factor. AND your MPG will get worse...:sad:...if you go with more cubes: You can say 'screw it' it's bad on gas anyway, but you'll cry at the pump!:noway:

I would avoid the thumper line of cams. I think you can find a dozen of far superior grinds that perform better. They are designed to sound "lumpy" without sacrificing street driveability, but it's a compromise and I think you can get more power from a less "gimmicky" cam.
Although I do agree that more cubes equals worse mileage, there are exceptions. Anyone remember the 307 vs 350? LOL! I had an e250 van with a v6 in it and another similar van with a 5.4 v8 and the v6 was a pig on fuel. It was guttless and I had to drive with the go pedal glued to the floor. I used to get cramps in my right foot! the 5.4 was far better on fuel and had more power. On another note my wife's 4.0 Jeep gets only 3 mpg. better than my Vortec 454 truck!

One other point of view is that a 396 has somewhat of a cool factor, since it was the original engine for an SS396. For my Saturday night cruise in car, a 396 or 327 would be just fine. It just happened to come with a 350 in it.
Nice point.. The little mouse can bite you in the ass at any time. I know this, and so do my BBC friends...:D High reving cubes can be a b i t c h..;)

You want gas mileage buy a Ford Focus or just get any of the others stated!!!!!!!!!!!!!!!!!!!!

In Ten years I've never checked my gas mileage. I can tell you it pretty much sucks. Bottom line, do you really care?


Rocky

You can build a 454 for no more money than a 396 and can make it look just like a 396 in the engine bay.

alright so i see some say keep the 396. would the 396 be any value to my car if it wasnt the original motor, but it is a '71 truck engine?

I went through the same problem when it came time to pick an engine.......396 or 454.
I didn't have the original engine so I decided on having the 454 I had built.
Boy, am I glad I did. More bang for the buck.
Cool factor? hehehe 396/325 horse or 460/480 horse?
What sounds cooler? LOL
As said, put a 396 sticker on the air cleaner and most don't know the difference.
Value? Non-original engine is a non original engine. I would pay more for the 454 car than a 396 all else comparable IF the original engine was not in the car.
A 71 396 is not a 396...it is a 402.
It all comes down to What Do You Want? Go for it!!!

since im gonna get **** for gas mileage with a 396 as some of you said, i was wondering if its better to just go 454 and get that added power. ive checked the internet and see that the 396 will get anywhere from 10 - 17 mpg, and that the 454 gets from 2 - 15. anyone from here have any numbers?

For what it's worth, my stock L34/TH400/3.31 gets 11.3 mpg with fairly normal driving. It costs me $25.00 in gas every time we go to see our grand kids and they're not that far away. It adds up real fast. With today's gas prices, your enjoyment level is directly proportional to the size of your wallet. It's easy for others to give you free advice when it's your money and not theirs. Think it through and base your decision on your own wants and needs.

You already have the 396. I would recommend just rebuilding that instead of investing in a new engine.

Gas mileage and classic muscle cars is an oxymoron.

yea but whats the deal with these 500 hp muscle cars that get like 20 mpg? are they ls motors or something? im not that deep into the motor history/parts yet, so i was wondering how the hell that is achieved?

Go with the biggest engine you can build. I got 14 mpg on the highway with a 454. :D

I'd keep the 396 for the nostalgia factor.

454's were produced by GM for three decades, the 396 came out in the mid 60's and by 1970 it was gone.

Regards,
-Greg

I'd keep the 396 for the nostalgia factor.

454's were produced by GM for three decades, the 396 came out in the mid 60's and by 1970 it was gone.

Regards,
-Greg


yea this is the 1971 396 (402) so idk how long the 402's were in production

just go 454. you will never second guess your decision. the mileage is going to be terrible on the 396 anyway, you might as well add a few more "smiles per gallon". I'm not stating anything that hasn't already been said, but the difference a mild 396 and a mild 454 is pretty profound. Unless its the original motor, imho, i can't justify building a 396. even if you are on a tight budget and debating trying to use what you have, in the end you are better off and saving for a bit longer and going 454.

as for 500hp cars getting 20mpgs...ls motors and overdrive trans, esp. t56

there is no replacement for displacement. I have a Vortecpro 505. Get the hint.

well the '71 402 motor sitting in it now is basically just a long block, if im correct. it needs a carb, intake manifold, air filter, fuel filter, some new headers most likely, seal kit, probably needs new pistons and it needs to have cylinder walls cleaned up. i think the heads on it might still be good though. but for however much that is gonna cost, would it be better to shell out 1100 right now and get a complete 454 with a 400 transmission?

just go 454. you will never second guess your decision. the mileage is going to be terrible on the 396 anyway, you might as well add a few more "smiles per gallon". I'm not stating anything that hasn't already been said, but the difference a mild 396 and a mild 454 is pretty profound. Unless its the original motor, imho, i can't justify building a 396. even if you are on a tight budget and debating trying to use what you have, in the end you are better off and saving for a bit longer and going 454.

as for 500hp cars getting 20mpgs...ls motors and overdrive trans, esp. t56


x2

well the '71 402 motor sitting in it now is basically just a long block, if im correct. it needs a carb, intake manifold, air filter, fuel filter, some new headers most likely, seal kit, probably needs new pistons and it needs to have cylinder walls cleaned up. i think the heads on it might still be good though. but for however much that is gonna cost, would it be better to shell out 1100 right now and get a complete 454 with a 400 transmission?

If you know it's a good motor.....YES!!! Buy the complete 454. You can sell the 396 long block for a few hundred bucks. At least the heads.. If you don't need the trany there's another $3-400. That's about half of what you spent back to help pay for goodies or whatever.

IF you've only got $1000 to spend then get some goodies for your 396. you could pay a grand for that 454 and it may not last a week. For sure, you can do more with the 454 but you already have the 396. Get some 781 or 049 heads and a decent cam for it and start from there. Later on if you decide you want more CI then get you a 454 when you have the extra money and work on it while your driving the SH&^ out of the 396 thats in your car. On top of that, lots of the parts, such as pulleys, accessories, and dress up stuff will interchange if you do a swap later.

Thumper cams have a reputation for sounding good at the expense of less power. They are a no go. Gas millage should be a little over 10 per mile if you drive with your head. Idling and stop and go traffic are the killers on the millage. I have run many small and big blocks and the larger cubes are very noticeable. If it is not an original engine then it doesn't matter, but more cubes equals more value. I would buy the 454 and sell the 396 to freshen the 454. Keep all your pulleys, brackets, and bolts. Don't forget to make sure the radiator is up to the 454.

haha everybody says something different :P

for your first car a 396 would problery more than enough yet if you have the opt. now get more cubes and a 4 banger for the week aka a saturn i love the mpg 28-32 to make up for the 5mpg on the weekeds. like metioned nobody buys a chevelle for mpg, yet if interested look into a ls motor swap you can find em at junk yards all day for a dd thats what i would do..... point being its your car the opt. are endless depending on your wallet if u got the 396 keep it great power. ps. watch out for the big mother thumpers had a buddy with sb and had some clearnce issues and had to do some over the top machine work. Best of luck and anything should be gravy....

I've been driving my 64 w/427 daily lately. I'm pulling down an impressive (not!) 11 mpg. It does make a difference when it's your daily driver. Mine's fairly radical for a driver, there's certailny wilder here on the board. Rect port heads, 260* @ .050 cam, 1000 cfm carb, backed by a Tremec. Before dialing in the carb, installing the Tremec and 3.55s, I had 4.56s and got a solid 4mpg. With a more modest combo, you should be able to pull better mileage out of it if you can keep your foot light. Either way you go, those are large cylinders to fill, and mileage will suffer.

I've even had the idea of running a mild, 220 horse 283, have most pieces to build, and swapping as needed. Would only take a couple of hours to do for real if everything was pre-set.

Devin

For anyone that drives a classic muscle car on a regular basis and is more concerned with gas mileage than originality, EFI, such as the new F.A.S.T. system and an overdrive transmission, either auto or stick is the way to go.

IF you've only got $1000 to spend then get some goodies for your 396. you could pay a grand for that 454 and it may not last a week. For sure, you can do more with the 454 but you already have the 396. Get some 781 or 049 heads and a decent cam for it and start from there. Later on if you decide you want more CI then get you a 454 when you have the extra money and work on it while your driving the SH&^ out of the 396 thats in your car. On top of that, lots of the parts, such as pulleys, accessories, and dress up stuff will interchange if you do a swap later.

not unless you get bigger domed pistons.....these heads have bigger chambers and they will kill your compression ratio in a 396

well i talked with the guy who owns the shop im building my car at, he says i should get the 454 cause you cant even build them for under 3 grand. and that if the engine does run and the 400 tranny that comes with it is in good shape then it would be a better deal than rebuilding the 396/402.

I bought the 67 in 1985. No engine.
Pulled a stock 454 out of a 74 Caprice Classic and put right in the Chevelle.
40K miles later in 1992, I parked the Chevelle to later someday restore it. 454 was still running good. Same engine in the car now but has now been built to be even better.
I drove that stock 454 back and forth to college 130 miles roundtrip daily, 5 days a week, for a couple of years. Never any problems except putting gas in it.
Best of luck with your decision. Thought this might give you food for thought.

follow brother kettbo's recommendations...

fwiw - removed my factory '67 396/325hp motor last year and put in a bored and stroked 4 bolt main 427 (now 496/607hp). it is like having 2 - 396's in it now. gas mileage has suffered as the q-jet equipped stock motor got a whole lot better mileage than the new motor with the 850 holley dp....the smile and pucker factor has went way up though !!....only driven on fridays and sundays now.....

ok so i got the info on the 454. its a complete 454 that was running when pulled. the 400 tranny is all there and in working order. they came from a 1976 car carrier. so im assuming he means like a truck/semi. its 1100, would it be a better deal than going through a complete rebuild on the 402 truck engine?

ok so i got the info on the 454. its a complete 454 that was running when pulled. the 400 tranny is all there and in working order. they came from a 1976 car carrier. so im assuming he means like a truck/semi. its 1100, would it be a better deal than going through a complete rebuild on the 402 truck engine?truck th 400's have a bolt on yoke,you will have to address that if you use the tranny

yea i decided to skip out on that engine, its a low horsepower highly worked 454 that doesnt fit me

If its a truck block then your going to have issues with clearance due to the engine being a tall deck configuration. That is if it is a truck block. But if its actually a 454, then its not a truck block. IIRC, all truck blocks were 427 cubic inches and not 454.

i learn something everyday. well for $1500 i can buy a mild 454 thats freshly rebuilt that was going into a 1984 monte carlo ss drag car or something. but i wonder if i should just go ahead and finish buying parts for the body to my chevelle and stop worrying about the engine for now.

$1500 for a freshly rebuilt 454 is a really good price.