Asking for engine advice 331 vs 347

[MPTech]

My Mk4 is turning 7 years old and I'm thinking about upgrading my 302 for something bigger next year, over the winter. Doing my research and planning now.
My current powerplant was rebuilt and has about 35k on it.
‘93 Mustang Roller 302
• GT-40P ported heads
• GT-40 intake (EFI with a modified chip ECU)
• FMS F-cam
• 30lb injectors + calibrated Pro-m meter

I had it tuned after it was built and it dynoed @ 287RWHP. This is very respectable and has been a lot of fun.

I'd like between 350 - 400hp. I want to stick with the 302 platform (if it was a new build, I'd be all-over a SBF 427!! or Coyote, but I don't want that much work & cost to upgrade, maybe next build)
I want to buy a crate with a warranty from a reliable builder (actually leaning towards a Craft Performance, we visited his place in 2018 and a couple guys in the club has his engines, They are awesome!).
I'm also wanting to run a Holley Sniper Stealth 4150.
Staying under 400, I'll be safe not running a Dart or aftermarket block.
This is 95% street, I've done a couple auto-cross and this might incent me to track it also.

Please educate me on the Pros & Cons of a 331 vs 347.
I have more than a basic understanding of engines, but still a lot to learn. I know the 347 (bored & stroked) is obviously more HP and torque, due to the addition of the stroke, but also understand that the 331 (bored only) is better for rpm(?) and easier on the components.
Are there any other pointers for my upgrade planning?

(If there are any existing posts on this, I'd appreciate a link. I couldn't find anything with a 331 / 347 search), but I did run across these two: Ford vs Dart Block (https://thefactoryfiveforum.com/showthread.php?35068-Ford-vs-Dart-Block&highlight=ford+dart+block) and: 4.000 & 4.125 Bore vs Stroke Combinations (https://thefactoryfiveforum.com/showthread.php?35073-4-000-quot-amp-4-125-quot-Bore-vs-Stroke-Combinations&highlight=331+347+engine+stroke)

[Jeff Kleiner]

In a nutshell and painting with broad strokes a 331 will be revvier and a 347 will be torqueier. Are either of those really words? Let's just say more revs vs more torque. For a primarily street car I'd go 347 and for more track use I might lean towards the 331.

Jeff

[wallace18]

I have done several Blueprint 347's are have been very happy with them.

[GoDadGo]

Rod angle is a bit better on the 331" kit since both kits typically run a 5.4" connecting rod, but you lose 16 cubic inches of displacement.
Either I think are good options if you are looking for a bit more bottom end grunt over the stock 302's 3.00 in stroke.

Overview of Scat's 331 & 347 Stroker Kits:
https://youtu.be/GNk6riUgeZc

302 Stock
4.000 Bore 3.00 Stroke

331 Stroker
4.030 Bore 3.25 Stroke

347 Stroker
4.030 Bore 3.40 Stroke

If you are going to buy a new Siamese Dart or Ford Block then consider either the ultimate 347 or a 363.

347 Big Bore Stroker:
4.125 Bore 3.25 Stroke

363 Big Bore Stroker:
4.125 Bore 3.40 Stroke

[rich grsc]

Well you know my choice Mark :D. Give Rick a call, I think he still has oil consumption issues? Why wouldn't just use the block you have? It's a good block and it would save you about a grand, and the turn around would only add maybe a week.

[scottiec]

If you are truly against an Dart block, which I highly recommend going with, I would probably go for the 347 for the extra cubes. There is a lot of back and forth on rod angle, but honestly wouldn't sweat it, especially since that has been addressed in the recent years (I want to say a change of location for the wrist pin, but I could be wrong).

HOWEVER - You can stick with your stock block and add some fancy new Trickflow 11r heads and a custom cam, you will absolutely make at least 350 to wheels. In fact, probably closer to 370-380.

It took me a couple of stock 302 blocks to go to a DART 363. I am very happy.

[TBull]

I'm kinda with Rich in this one and go to the 331. Solid block, then I'd send the block to someone local. Morley Performance? and have them build you the short block. They'll take care of all of the exact tolerances build. I'd have them put it together with Main studs and 1/2" head studs. I'd go with the AFR 185 heads and probably a Victor Jr Intake or something comparable. The Holley Sniper will bolt right to the top and it handles the fuel injection. Don't forget the fuel supply. You'll need a higher than stock fuel pump. Once you're together, I'd send it to Bob Monks for a tune. Like Rich said, we can help with the rest. It'll be fun! Don't forget too that as you increase HP, all the other system will be stressed. Not a bad thing, but just be aware. I know I found out the hard way as you know. Snapped 2nd gear in my T5 after 4 years. Just my .02.

[Real time recon]

My Mk4 is turning 7 years old and I'm thinking about upgrading my 302 for something bigger next year, over the winter. Doing my research and planning now.
My current powerplant was rebuilt and has about 35k on it.
‘93 Mustang Roller 302
• GT-40P ported heads
• GT-40 intake (EFI with a modified chip ECU)
• FMS F-cam
• 30lb injectors + calibrated Pro-m meter

I had it tuned after it was built and it dynoed @ 287RWHP. This is very respectable and has been a lot of fun.

I'd like between 350 - 400hp. I want to stick with the 302 platform (if it was a new build, I'd be all-over a SBF 427!! or Coyote, but I don't want that much work & cost to upgrade, maybe next build)
I want to buy a crate with a warranty from a reliable builder (actually leaning towards a Craft Performance, we visited his place in 2018 and a couple guys in the club has his engines, They are awesome!).
I'm also wanting to run a Holley Sniper Stealth 4150.
Staying under 400, I'll be safe not running a Dart or aftermarket block.
This is 95% street, I've done a couple auto-cross and this might incent me to track it also.

Please educate me on the Pros & Cons of a 331 vs 347.
I have more than a basic understanding of engines, but still a lot to learn. I know the 347 (bored & stroked) is obviously more HP and torque, due to the addition of the stroke, but also understand that the 331 (bored only) is better for rpm(?) and easier on the components.
Are there any other pointers for my upgrade planning?

(If there are any existing posts on this, I'd appreciate a link. I couldn't find anything with a 331 / 347 search), but I did run across these two: Ford vs Dart Block (https://thefactoryfiveforum.com/showthread.php?35068-Ford-vs-Dart-Block&highlight=ford+dart+block) and: 4.000 & 4.125 Bore vs Stroke Combinations (https://thefactoryfiveforum.com/showthread.php?35073-4-000-quot-amp-4-125-quot-Bore-vs-Stroke-Combinations&highlight=331+347+engine+stroke)

Why not beef-up what you have ???
https://www.hotrod.com/articles/ccrp-0807-479-hp-ford-302-short-block-build/

[Avalanche325]

At anything under 550hp a stock block is fine.

A 331 is bored and stroked. A bored only 302 (to 4.030") is a 306. A 347 is just stroked more.

I don't see any reason not to go 347. More power and more torque for only a few more dollars.. The block clearancing is hardly anything. Oil consumption issues were figured out many years ago. Rod angle is also not an issue. Not technically as good as a 331. But then a 331 doesn't have as good a rod angle as a 302. The same goes for 302 to 289. If someone is having oil consumption issues, there is a problem, it is not because it is a stroker unless they did some wacky combination.

However, the first thing to do on a SBF is to put aftermarket heads on. You cannot port factory heads of any casting enough to even equal a cheap set of aluminum aftermarket heads. A 347 can move a LOT of air. You need good heads to support that.

I agree that if you have a good block why not use it.

[skidd]

This is 100% superficial... and my own bias... but .. the 347 for me sounds better rolling off the tongue than the 331.
Yeah.. Yeah.. I know... WTF!!! I can't explain it... but I think it's the 7 at the end.
to my ears.. a SB327 just sounds tougher than a SB350
A .357mag "sounds" like more than a .44mag
And.. a 347 just sounds like more than a 351.
I attribute this to the SideOiler 427. If it has a 7 at the end.. it just has to be awesome!! :)
One day my 302 (which I love) will give-up-the-ghost. What ever it transmographies into.. it'll have a 7 at the end.

[bobl]

The heads, cam and intake combination will for the most part dictate how much power you get. All else being equal the 331 would require a couple hundred more rpm than the 347 to make the same power, and peak torque would also occur at a higher rpm. Depending on how you use it, more rpm and less low end torque can sometimes be an advantage in these cars. I don't think it really matters which way you go. Spend your money on cylinder heads and intake system.

Bob

[stack]

unless you are changing the heads, cam it may not be worth it. I think a nice set of aluminum heads will get you to the power you want without stroking the engine.

stack

[rich grsc]

Mark, I know how you like to drive, you like to spin the engine. ;) I've ridden enough with you to know, you're in 3rd gear at 5000 rpm's :rolleyes:, when I'd be in 5th at 2200. A 331 will like the higher rev's better than a 347.
Just saying......