Blueprint 302 vs 347

[Afdent11]

Hey guys,

I’m wondering if someone who has heard or driven both of these engines could provide some feedback on the engine feel and sound characteristics. I don’t think I need the extra power of the 347, but I’m considering it because I’ve heard it has a pretty great sound. But maybe it’s indistinguishable from the 302?

Any insight you could provide before I order would be great. Thank you!!

[rich grsc]

It's the same engine, just different bore & stroke.

[drewr]

Same block. Big difference. Just as you noted, a 347 will have more power. A 302 has a lot of power, too, so it depends on what you want. Also, bigger displacement seems to improve resale value, if that is a consideration. Size of block and look will be the same in the engine bay.

[rich grsc]

Nothing to do with sounding different

[Afdent11]

Thanks guys. Yeah I knew it was same block, but the rep at blueprint said the 347 had a different cam and so it had more of a “lopey” idle. I just don’t know how to know what’s accurate without just getting others thoughts or experiences

[Papa]

My 347 idling at 800 RPM ...


https://youtu.be/doBle7rb7hI?si=CAEXB3lowBeb4Umr

[Waterman]

My recent BP 347 with sniper2 has a pretty good sound at idle.
https://youtube.com/shorts/vyXEXuSm-LI?feature=share

[Papa]

Contrast the first video with this one of the same engine getting tuned on the dyno after converting to 8-stack EFI. I also swapped the FFR pipes to Gas-N pipes:


https://youtu.be/GOY7IQuik_c?si=e2H_WhePW0rYIk6g

[Afdent11]

Thanks guys! Those sound amazing! To my ear, they sound very similar to the 302 that we put in at the build school. So now I’m wondering if the drive-ability might be a little better with the 302 in such a light car. The one at the build school dynoed at 395 which seems like more than enough for this car. Price isn’t really too much of a factor since the 347 is only $800 more. Just looking for the better fit. I guess it’s all just preference.

[gbranham]

For $800 more, why wouldn't you get the 347? Dimensionally, its identical to the 302. I've built a 302 FFR and a 427 FFR. I'll never go back to a 302. Get the extra HP so you have it on tap if you want it.

Greg

[PMD24]

Both of the instructors that I had at the build school said that the 347 is the perfect engine for this car.

Pat

[RJD]

Another thing to consider is what you plan to use the car for. In my case, my interests were car shows, cars & coffees, and cruising - no plans to autocross or race. With that in mind, I went with the Blueprint 302 which came with the attached dyno sheet. Most of my cruising is on Virginia winding country backroads with speed limits between 35 and 55 mph. Occasionally to get to these cruising grounds, I take the freeways with 70 mph speed limits. In either case, the engine just purrs along, ready to go with more power than I'll ever need or want. So in my case, the 302 was a good fit, and $800 bucks can buy you a lot of other car stuff. Just my preference.

223216

[CraigS]

I always like more cubes. To get a given HP the larger cube engine can be tuned more mildly so it's more driveable.

[mgk172]

I went through the same debate for mine… 302, 347, coyote? At the end of the day, I wanted a true pushrod motor with the added power. My thoughts were similar - will it be drivable or an out of control beast? The control is all in your right foot. An irresponsible right foot in a 302 is way more dangerous than a responsible right foot in a 347.

A buddy of mine had a 347 in his and it was awesome. He ended up swapping out to a 427 after a few summers of driving.

I went with a carbureted 347, 3.55 rear & 0.68 5th gear. The car drives like a dream! It’s easy to drive for a mild country drive but can get wild if/when I want it to. (I’m getting for spring and to drive it again after typing out this post! It’s too dang cold here!)

Sure, a 302 is perfectly fine for those cars and will be loads of fun to drive. But, if you are asking my opinion, an additional $800 is worth the upsize.

[J R Jones]

Your question is about sound and feel. "Feel" is a bit ambiguous, vibration?
All things being equal you and me could not tell the difference from displacement.
The sound and feel come from the exhaust, heads, and cam.
Tuned headers flow better and radiate sound through thin wall tubes.
The heads with big valves (Shelby, GT40 type) flow better, bigger noise.
Higher compression ratio influences exhaust sound.
The cam duration and timing are the biggest influence.
The two displacements constructed and tuned to street OEM specs will not sound exotic, and they will sound similar.
The sound you are looking for comes from race spec build and tune.

Big block engines do have a different sound, maybe the big bang principle with lower RPM.
jim

[UpNorth]

I wanted first a 302 from BPE but ended up buying a 347.
Like some said: 800$ for more power is not that much and I was advised to go the 347 way to get more $ if ever I wanted to sell.
That remains to be proven.
Just my 2 cents.

Merry Christmas!

[wheelindex]

It is a hard call between engines always. I honestly am going 427 just for the number. I think a 302/331/347 produces more than enough power than 99% of could handle. It would be interesting to see people post the heads/cam specs with duration/lobe separation to make comparisons. Great videos above!

[Papa]

It would be interesting to see people post the heads/cam specs with duration/lobe separation to make comparisons.

My head and cam specs:

Heads:
BluePrint Performance Aluminum
58cc chamber
Hardened retainers and springs
2.02 swirl polished intake valves
1.60 swirl polished exhaust valves
(BP Aluminum Head Part# HP9009)

Cam Specs:
Roller,
.543 Intake .554 Exhaust & 218 Intake
226 Exhaust duration @ .050 - 112 degree lobe separation

https://thefactoryfiveforum.com/attachment.php?attachmentid=84569&d=1524421786

[CraigS]

Even before I went from 351 to 408 I worked on the gas pedal both cable and later linkage versions. I went for about 1/2" increased travel at the pedal. This helped a lot w/ better fine control of HP use.

[Mike.Bray]

https://thefactoryfiveforum.com/attachment.php?attachmentid=84569&d=1524421786

I finally got around to getting my engine on the dyno Dave.

223249

[MaxVmo]

After the research and multiple sources of info found here (Papa’s build especially), I went with the 347 package from BPE. Dyno has similar numbers to the chart above, more than enough for my needs. Very happy with my choice.

[Afdent11]

Thanks guys! All of this information is so helpful. I think I’ll go ahead with the deposit on the 347.

[MaxVmo]

Keep in mind the power steering option!

[rponfick]

Keep in mind the power steering option!

Ditto that. I have built two without and wished I had it. Did the '35 pickup with FFR electric PS, and loved it. Current Mk5 build has BP PS option on their 347. Never felt need for power brakes.

Ralph

[Afdent11]

Keep in mind the power steering option!

Yes I’ve requested the PS and A/C :). Thank you!

[MPTech]

When I built my MK4 13 years ago, I bought a healthy re-built 302. Dyno'd 290 RWHP. It was fun to drive and I've put about 35k miles on it and throughly enjoyed every mile. After about 10 years, performance was down a little and it was having some blow-by and I was itching for a few more HP, so I went through my options. I considered a 427 SBF, but cost and additional issues (replace headers, taller deck, etc) I decided to go with 302 platform. I knew if I just rebuilt mine as a 302 or 306 I'd regret it, so I ended up having mine rebuilt and bored/stroked to 347. My engine builder dyno'd mine @ almost 500 HP. I'm LOVING it and can't wait to take it auto-Xing and/or on the track.
I highly recommend the 347 and PS & PB! Just Do It

[TrackDay17]

I'm building my car right now and I went with the 347 because the price difference wasn't much.
Mine made 424 horsepower and I think it was 418 torque, I don't have my dyno sheet nearby.
My local friend builders here recommended going with the optional 0.68 overdrive instead of the 0.86 I think it is.
Cruises a little lower rpm in top gear for highway runs.

[Ford & Jeep Fan]

I always like more cubes. To get a given HP the larger cube engine can be tuned more mildly so it's more driveable.

This Is the best idea. lower revs are a littler easier on parts as well and cost less and last longer to maintain in the long run.