Crazy, weird question: gas mileage on a Mk 4 roadster?

[Grubester]

I'm building a 289 USRRC-version with a BluePrint carbureted 347. Engine will arrive late next week, but that's early for when I'll be able to actually install it.
I was just curious about experiences people have had with similar builds.
I know, gas mileage shouldn't be an issue if building such a car, but still...

[cv2065]

I'm building a 289 USRRC-version with a BluePrint carbureted 347. Engine will arrive late next week, but that's early for when I'll be able to actually install it.
I was just curious about experiences people have had with similar builds.
I know, gas mileage shouldn't be an issue if building such a car, but still...

Plan $25-$30 a ride. :)

[egchewy79]

I have a 289 HiPo, FiTech EFI, getting around 15mpg w/ combine highway/local driving.

[Jeff Kleiner]

Regular, run around cruising with some “spirited” blasts will probably see 14-15ish. That’s what I got with mine with EFI anyway. Interstate trips running at 75-80 MPH would deliver 22+. Track days ran about 6 MPG and I’d have to fill up after two 15-20 minute sessions!

Jeff

[AA-ron]

I have a 302 crate and have put about 6500 miles on it over the past year and a half. I started with a Sniper EFI and then added a full Sniper Hyperspark system (now the EFI controls timing). I bring this up because I was initially getting 12 to 15 MPG on regular cruises. Since I added the Hyperspark I'm getting numbers centering around 18 MPG.

[Jeff_J.]

I installed the BP 347 w tremec 5spd - I recently had it tuned for cruise/touring type driving and I got 26 MPG on my last highway run 3 hours at around 68 MPH ~ 2,000 RPM. Combined I expect around 18. Maybe I don't have as heavy of a foot. "not Judging" LOL..

[daberry]

I have a carbureted 347, 3.31 gears. I get 25 frequently.

[GoDadGo]

20.0 MPG @ 83 MPH 383 SBC (Dark Side) on the Interstate @ 2,000 RPM.
.......MY .50 / O.D. 6th Gear Really Rocks With My 3.73 Ring & Pinion Gear!
14.0 MPG General Driving & Not Being Too Stupid.
10.0 MPG Having Fun On Da-Back-Roads-Dawlin Havin Fun.
3-5..MPG Making Passes At The Drag Strip.
11:30 @ 124 MPH Best Time With A Very Sad 2.57 Second 60' Time On Nitto 555's 320 Tread Wear Tires.
I've since upgraded to Nitto NT-05 200 Tread Wear tires but have failed to make any new passes on these tires.

SPEC LINK: .. https://www.factoryfive.com/whats-new/customer-steve-l-graduates-his-mk4-roadster/

[ProfessorB]

427 Windsor here, carbureted with 3.55's. 12 MPG

[Grubester]

Wow -- 12 MPG. I know, 427. Mine is a carbureted 347 and also 3.55 tail gears (the "standard TKX 5th gear overdrive"... whatever that is)
Thanks! Quite a range of MPG numbers -- no surprise, considering all the HW configurations and driving styles. Again, Thanks!

[DanQ]

On my '33 Hot Rod (stock 5.3 LS/4L60E/3.00 axle) will consistently give me 24 mpg. We drove it up to the cabin for winter storage this past weekend, 160 miles on 6.5 gallons of gas, or almost 25 mpg. This was a mix of small towns and some 70 mph freeway driving. I went with the highway gears to keep rpm's low at highway speed so the exhaust noise is next to nothing. I am turning only 1,500 rpm @ 55 mph. Considering it is such a light vehicle, I figured there would be no need for steep gears, as starting off still gives me all the acceleration I ever want. I am pleased with that gear selection and would do it again.

205496

[Theshandman]

BPE 347 Tremec TKX. 12-15. I'm about to revisit the Sniper config.

[Mbufford]

I’d like to hear some reports from coyote builds. Driven conservatively, they should offer really good mpg, as if I would ever drive like that.

[JMD]

Wow -- 12 MPG. I know, 427. Mine is a carbureted 347 and also 3.55 tail gears (the "standard TKX 5th gear overdrive"... whatever that is)
Thanks! Quite a range of MPG numbers -- no surprise, considering all the HW configurations and driving styles. Again, Thanks!

You're going to want to get the .68 TKX overdrive gear if you want good (I mean 'better') mileage. On BP website I think they send it with the .82 5th gear ratio unless you request otherwise. You may want to double check which one you're getting if you don't know. I think it's the same price for either one. The .68 is the way to go...especially with 3.55 rear gear.

[Al_C]

I've been trying to think of a way to respond to this thread without sounding sarcastic or disrespectful to the original poster. Here goes! I am amazed at how many people have responded (13 including myself) to a question that I, personally, did not consider. Nevertheless, a number of you have replied with actual results! As far as Mbufford's question about coyote mileage - I have no clue. I know I can get to Kleiner's on a single tank. I have to fill up once between home and Columbus, and it will always need gas when it is raining the hardest.

[Papa]

I was tracking my fuel mileage for about a year on my BPE 347 with the Holley Sniper EFI. I was typically seeing 14'ish m.p.g. with some lower and some higher numbers depending on the type and duration of driving. My lowest was under 10 and my best was 18. I was using the FillUp app for Android available for free on the Play Store.

[Dgc333]

My Speedstar with a 345(5.7) Hemi, Tremec T5 and 2.73 gears gets 20-21 mpg around town. Have not had it on a long enough trip to assess the highway mileage.

[ggunter]

Whatever fuel mileage you get multiply that by a factor of ten to get your smiles per gallon. Some guy at the gas pumps the other day was telling me what bad mileage I must get. I told him I didn't care if gas was $10 a gallon, you'll never have more fun with your pants on.