[1baddgarage]

Alright I'm trying to decide whether to go with a 347(4.00 x3.470) or a 371(4.125 x 3.470) world products short block. This will be my daily driver for about a year at least, while I attend UTI and I want at least somewhat decent mileage. What are you guys getting for MPG with a 347?

[Mlx50man]

whats the rest of the setup going to be?? we need more info.

[89LX347]

with old 347 i got 21 mpg.

[e3sean]

20mpg is attainable depending on the rest of the mods you have. but its also how heavy ur foot is.

[1baddgarage]

The rest of the set up should be AFR 205 heads, Comp cams NX274 Cam HR, Trick flow R intake, TKO 600, and 3.73 rear gears. I know some of this is going to hurt my mileage, but I'm looking for a mix of power, reliability and mpg. Mid to upper teens on the highway is good enough for me. Do you guys think that is relistic? I already have an AEM standalone so dialing it in shouldn't be an issue.

[1slo5.0]

Originally Posted by 1baddgarage Alright I'm trying to decide whether to go with a 347(4.00 x3.470) or a 371(4.125 x 3.470) world products short block. This will be my daily driver for about a year at least, while I attend UTI and I want at least somewhat decent mileage. What are you guys getting for MPG with a 347?

347 is 4.03 x 3.40. Your other combination (4.125 x 3.47) is a 371 but that stroke is uncommon, I've never heard of it. The other more common combination is 4.125 x 3.40 which is a 363 or 4.125 x 3.25 which is a 347. An efficient combination will produce the best power and fuel economy, not random parts out of a catalog. A friend of mine has a 347 in his 88 GT and it makes 440hp at the tires and gets 25mpg on the highway. He has hours in tuning though.

[89LX347]

Originally Posted by Darrell 347 is 4.00 x 3.40. Your other combination (4.125 x 3.47) is a 371 but that stroke is uncommon, I've never heard of it. The other more common combination is 4.125 x 3.47 which is a 363 or 4.125 x 3.25 which is a 347. An efficient combination will produce the best power and fuel economy, not random parts out of a catalog. A friend of mine has a 347 in his 88 GT and it makes 440hp at the tires and gets 25mpg on the highway. He has hours in tuning though.

i am assuming you were trying to say a 363 is 4.125 x 3.4

[1baddgarage]

Originally Posted by Darrell 347 is 4.00 x 3.40. Your other combination (4.125 x 3.47) is a 371 but that stroke is uncommon, I've never heard of it. The other more common combination is 4.125 x 3.47 which is a 363 or 4.125 x 3.25 which is a 347. An efficient combination will produce the best power and fuel economy, not random parts out of a catalog. A friend of mine has a 347 in his 88 GT and it makes 440hp at the tires and gets 25mpg on the highway. He has hours in tuning though.

The bore and stroke on a conventenial 347 is 4.030 x 3.40. The short blocks I'm looking at are Based on a world prodocts man o war block and they start with a 4.00 bore and a 4.125 bore so that leads to the uncommon stroke of 3.470. The short blocks are built by world products themselves and are really stout. But hearing that 20+ mpg is doable, is what I really wanted to hear. Thanks for all the info

[89LX347]

Originally Posted by 1baddgarage The bore and stroke on a conventenial 347 is 4.030 x 3.40. The short blocks I'm looking at are Based on a world prodocts man o war block and they start with a 4.00 bore and a 4.125 bore so that leads to the uncommon stroke of 3.470. The short blocks are built by world products themselves and are really stout. But hearing that 20+ mpg is doable, is what I really wanted to hear. Thanks for all the info

thats a pretty big head your planning on running, an reason why? your cams not that big at all.

[95StangMX]

I love posts like this.......its almost as bad as....Thinking to go Twin Turbo or Supercharger? My goal is like 7,000 HP. Which one will get me the best MPG and be the most reliable cause I have to drive 9,873 miles each way every day to college......does nobody remember.....fast, reliable, cheap, pick 2........
EDIT: or Fast, reliable, and good MPG pick 2

[baine21225]

i get 29 MPG


































in my hyundai

[91 gt 5.0]

I didn't see the word cheap anywhere. Looks like he wants fast and reliable. I'm not denying that this is like many other posts, but he never really talked about cheap.

[95StangMX]

OK thats a different example the first one was about wanting a bizillion HP and 50MPG...and it goes without saying if you are looking for good gas mileage in a race car you are cheap.....you want good gas mileage buy a hybrid

[1slo5.0]

Originally Posted by 89LX347 i am assuming you were trying to say a 363 is 4.125 x 3.4

Correct, my bad. Fixed both errors.

[1slo5.0]

Originally Posted by 1baddgarage The bore and stroke on a conventenial 347 is 4.030 x 3.40. The short blocks I'm looking at are Based on a world prodocts man o war block and they start with a 4.00 bore and a 4.125 bore so that leads to the uncommon stroke of 3.470. The short blocks are built by world products themselves and are really stout. But hearing that 20+ mpg is doable, is what I really wanted to hear. Thanks for all the info

How much horsepower are you trying to make? I wouldn't waste the money on a World or Dart block if you never plan on exceeding 500hp at the tire. I don't see the point in running an uncommon stroke either. 347 kits are cheap these days. Fordstrokers.com has all kinds of different kits available.

[1baddgarage]

Originally Posted by Darrell How much horsepower are you trying to make? I wouldn't waste the money on a World or Dart block if you never plan on exceeding 500hp at the tire. I don't see the point in running an uncommon stroke either. 347 kits are cheap these days. Fordstrokers.com has all kinds of different kits available.

I'm hoping to achieve around 450 HP to the tire, all motor, for now. Which shouldn't be a problem. With the world short block I'll have around 9:5.1 compression ratio so boost is in the future. I already have a 308 with a procharger that's close to the factory blocks limits. I just want a decent cubic inch starting point for now, that'll handle what I through at it in the future.

"thats a pretty big head your planning on running, an reason why? your cams not that big at all."

I'm running that big of a head because I'm planning on forced induction, and I'm also leaning towards the 371 short block.


95StangMX
Hybrids aren't my style...but thanks for all the help

[95StangMX]

Factory block will handle 450 all day long.....we are just trying to help you. You are concerned about MPG but you are gonna throw away all that money on a block you dont need...and if you goal is only 450 you can hit that with a N/A 347 that is well built and matched..BTW its a lot easier to hit the quote button on the right bottom side of a post then to type it all out

[1baddgarage]

Originally Posted by 95StangMX Factory block will handle 450 all day long.....we are just trying to help you. You are concerned about MPG but you are gonna throw away all that money on a block you dont need...and if you goal is only 450 you can hit that with a N/A 347 that is well built and matched..BTW its a lot easier to hit the quote button on the right bottom side of a post then to type it all out

My real goal isn't only 450 RWHP, It's 750- 800 RWHP with forced induction. I'm building it all in stages, that's why I want to start with a good short block. Otherwise I'd build my current factory block, but I want to build it right the first time instead of building it twice. I'm not all that concerned with mpg, if it's anywhere in the mid to upper teens range I'm fine with that. I just wanted to see what everyone else was getting for mpg, because it made a difference on my cubic inch decision.
thanks for the quote tip

[1slo5.0]

Originally Posted by 1baddgarage My real goal isn't only 450 RWHP, It's 750- 800 RWHP with forced induction. I'm building it all in stages, that's why I want to start with a good short block. Otherwise I'd build my current factory block, but I want to build it right the first time instead of building it twice. I'm not all that concerned with mpg, if it's anywhere in the mid to upper teens range I'm fine with that. I just wanted to see what everyone else was getting for mpg, because it made a difference on my cubic inch decision. thanks for the quote tip

700-800 rwhp and you want fuel economy??? You are going to have to take a way different approach at building this engine. Buying an assembled production line shortblock isn't going to work. You are going to need a piston with a ring stack a little lower on the piston than a conventional engine. All of your piston to wall, ring end gap and other clearances are going to have to be set according to the level of boost you plan on running. You are going to have other major things to address as well such as fuel system, roll cage, transmission and rear axle. Get your check book out.

[Sleeper_Stang_89]

Originally Posted by Darrell 700-800 rwhp and you want fuel economy??? You are going to have to take a way different approach at building this engine. Buying an assembled production line shortblock isn't going to work. You are going to need a piston with a ring stack a little lower on the piston than a conventional engine. All of your piston to wall, ring end gap and other clearances are going to have to be set according to the level of boost you plan on running. You are going to have other major things to address as well such as fuel system, roll cage, transmission and rear axle. Get your check book out.