383 Guys, I Need Some Input.

[Scootin 81 C20]

Hey guys. I am looking into getting a street/strip ready 383 stroker. The guy I am getting it from says I'll get 12 MPG out of it as long as I don't put it to the floor. I am needing input on what MPG you 383 guys are getting. Can you shoot me some figures please?

Thanks
Benjamin.

[westofb]

If you are putting in a hopped up motor, why the concern with fuel mileage? I doubt a healthy 383 in the squares will get that good, well u less you let it idle as you hurl it off a big cliff.

[85Bowtie]

Depends on how street/strip the motor is. Generally, if you're doing a 383 stroker you tend to put on parts that aren't gas mileage friendly....

I would say 10 or so around town, 12-14 hwy. Like the other guy said, why are you concerned with gas mileage with a 383?

[63chevyll]

what gears and tires also???

[Scootin 81 C20]

The reason I'm concerned with mileage is that the truck is daily driven. The biggest reason I'm looking at getting it is the guy made me a deal I can't pass up on the engine he's selling. Race ready 383 stroker putting out 725 HP. for $700. He's also including a Fairbanks Stage 3 Street/Strip TH 350 or TH 400. That's why I'm wondering the mileage, it's too good to pass up.

My gearing is probably a 4:11 and my tires are factory size on 16.5 steel wheels.

[rickymac85]

WOW! thats pretty far out. 700+ horsepower out of a street/strip 383? That guy is crazy, unless it has a supercharger or something. But if it really does have that many horses, its not going to be very streetable at all for a dd. just my .02

[85Bowtie]

725 HP out of a street/strip 383? Surely you don't believe that. Almost 2 HP per cubic inch huh.....

I've never heard so much BS about HP figures, engine displacements etc than I have lately both on the internet and the backyard jackasses I run into at car shows and such.

April Fool's is long over....

[Edgel82c10]

I have a 383 in mine and it was put on the engine dyno and I get about 5 to 8 miles to the gallon and it has 405hp and 440tq.

[Scootin 81 C20]

That figure IS NOT what my particular engine has, it is what a nearly identical engine in a mud truck is running.

The engine I am getting has 2 950 Holley double pumpers topping a tunnel ram, its had the heads worked, ported and polished, 1/4 or 3/4 solid race cam, high flow water pump, and I think he said it has Hooker headers with 2 inch primaries and a 3 inch collector. IDK much about the internals and neither does he because this engine was built by his fathers race shop about 4 years ago. He is a professional racer though. He runs in the class directly under the funny cars.

Even if it doesn't live up to the numbers he's giving me, it'll still have more power than my Goodwrench "Target" 350 that has maybe 250 HP. I'll be happy with it either way cause I can guarantee it to have more power than I have now.

[68Timber]

Originally Posted by Scootin 81 C20

That figure IS NOT what my particular engine has, it is what a nearly identical engine in a mud truck is running.

The engine I am getting has 2 950 Holley double pumpers topping a tunnel ram, its had the heads worked, ported and polished, 1/4 or 3/4 solid race cam, high flow water pump, and I think he said it has Hooker headers with 2 inch primaries and a 3 inch collector. IDK much about the internals and neither does he because this engine was built by his fathers race shop about 4 years ago. He is a professional racer though. He runs in the class directly under the funny cars.

Even if it doesn't live up to the numbers he's giving me, it'll still have more power than my Goodwrench "Target" 350 that has maybe 250 HP. I'll be happy with it either way cause I can guarantee it to have more power than I have now.

Two things, a tunnel-ram 383 with dual 950 Holleys will never do 12 mpg.

And there's no way anyone would sell a motor like that for that price in their right mind. The carbs alone cost more than that.

This falls under "If it's too good to be true... "

[Scootin 81 C20]

Bruiser, the guy has 9 of them sitting in crates. They've been sitting for 4 years and he's almost 60 years old. The mileage can't be much worse than what I get now running down the road at 2,500rpms.

[foamypirate]

You're gonna hate driving an engine like that on the street, despite what you think.

[swb85]

I don't even know where to start on this one.

You're likely going to be able to watch the gas gauge move. Who says this thing will even run on pump gas? A "3/4 race cam and worked heads" tells you zip about that motor, it could be a high compression lump that doesn't get up on the cam until 4000rpm. Just because it's a good price doesn't make it a good deal or even a good idea.......

[Scootin 81 C20]

Here's my other choices, all SBC. 377, 383, and a 409.

[68Timber]

Originally Posted by Scootin 81 C20

Bruiser, the guy has 9 of them sitting in crates. They've been sitting for 4 years and he's almost 60 years old. The mileage can't be much worse than what I get now running down the road at 2,500rpms.

swb85 is right. There's so many problems with the description you don't know where to start. But I do know that if you want to assume this guy is honest and the engine is great and the $700 price is fair, you're taking a huge leap of faith. But if you think your mileage can't be much worse that what you get now, try it and see. I'd bet 4 to 5 mpg.

Anyway, I didn't post anything to be rude or anything. Honestly, it's just flat out fishy as hell and I think he's trying to get one over on you because of your age. I'd hate to see you spend that money and end up with something that ran poorly.

[68GMCCustom]

If these motors truly have massaged 700+hp parts in them...then they are probably worth more then $1 per hp.

My 383 stroker has a single holley 650 on a Holley street dominator manifold and has a small Melling cam (maybe someone somewhere might call it a 1/4 race?) and makes maybe 400hp/400+tq at the crank. With 3.73's it might get 12mpg on the highway.

An overdrive (or really tall gears) to reduce cruise rpm's will do the most for better fuel economy.

[westofb]

I would say buy them all, sale the extras and have yours for free plus some coin in your pocket....I would be very skeptical, it truly sounds too good to be true. Like someone pointed out, the tunnel ram and the 2 950 carbs are worth way more than what he is asking for the complete 700+ hp engine. With those carbs you will be lucky to see anything close to 10 mpg, maybe get 5 mpg if you are lucky. Unless you are plaining on turning your daily driven 3/4 ton into a drag truck, I would say stick with the motor you got.

[fire120ball]

Everyone is being so negative, I think that sounds like a hell of a deal. And even if it's not 750 HP you can't pass that up. Go for it man

[T/C]

Originally Posted by fire120ball

Everyone is being so negative, I think that sounds like a hell of a deal. And even if it's not 750 HP you can't pass that up. Go for it man

They are not being negative.. They are just telling someone to watch out and make sure they are not getting in over there head... Or screwed..

[85Bowtie]

Originally Posted by Scootin 81 C20

They've been sitting for 4 years and he's almost 60 years old..

As long as he's not dead, nobody is ever too old to screw you over.

Personally, I don't see a naturally aspirated, non nitrous or any of that other bs, 383 making 725hp just because of a tunnel ram and a pair of Holley's plus a cam that has no real specs given.

If you're confident with the guys good nature, spend the $700 and give us the result.

[68GMCCustom]

Originally Posted by fire120ball

Everyone is being so negative, I think that sounds like a hell of a deal. And even if it's not 750 HP you can't pass that up. Go for it man

....comes from years and years of experience...with those that don't carry the same morals as most of us do.

[fire120ball]

Originally Posted by 68GMCCustom

....comes from years and years of experience...with those that don't carry the same morals as most of us do.

Very true, I stand corrected

[Chavyluv79]

Well i have a 383 in my 4wd with 35s and 307 gears i get about 10 on the city and about 15 on the free way i have about 400 hp

[Pyrotechnic]

Sounds more like dirt track claimer motors to me, and for $700 that is OK, but I would make sure that the compression ratio will allow for pump gas. At the very least you will want a cam swap since an all out race cam will be meant for a sustained 4000+ RPM.

Either way, I would go over any motor with a fine toothed comb before spending more than the value of a rebuildable core for it.

[68Timber]

I've got major issues with this man and his claims about this engine. I've already mentioned the tunnel ram and dual 950 Holley's being worth more than the asking price. Since the thread is still alive I have to bring up the heads.

He is flat out crazy or is trying to rip you off. I'll have to make a few more logical assumptions first. If this engine had good aluminum heads, they'd cost another grand alone (on top of the dual 950 Holley's on a tunnel ram) so the math once again doesn't add up. (This critique can go on and on...) So I'm assuming that since you said the heads were ported and polished they are factory iron heads.

I know for a fact that factory iron heads will support 750 hp on the dyno. I know someone personally who builds these heads and I've seen the dyno runs to back it up. But he's older now and only makes them for himself and a very few close friends. He charges $30,000 a pair. The runners are filled and ground and filled and ground until the intake runners are a straight shot to the cylinders but they still cc the same as stock heads - a NHRA requirement. He races all the NHRA meets, and has three cars. He races stock and super stock. Super stock is the only class that allows these highly modified heads. Google Bob Dennis NHRA, Bob Dennis stocker, Bob Dennis super stock.

So, yeah. Iron heads can make 750 hp on the dyno.

There's no chance in hell this seller is telling you the truth, and I really do hope you don't buy from him and quit talking to him.