• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

331 vs 347

  • Thread starter Thread starter 1991vert
  • Start date Start date Jul 19, 2005
Prev
  • 1
  • 2
First Prev 2 of 2

89CopCoupe

Banned
Feb 17, 2004
606
0
0
Post Count City
Jul 24, 2005
#21
  • Jul 24, 2005
  • #21
Grn92LX said:
I care about money more than power And I REFUSE to EVER put a cowl hood on my car. I would have needed one to run the right efi intake on a 408. Believe me, I considered it, then I realized a 347 was my only real bet.

Mike
Click to expand...

Well, I'll have to make the drive out to NY so my 331 can put the spank on your 347

Joe
 

Grn92LX

Fidanza Man!
Founding Member
Jan 14, 2001
6,819
64
129
New York
Jul 24, 2005
#22
  • Jul 24, 2005
  • #22
Lets do it!!

Whats your combo by the way? I didn't know you had a 331.
 

89CopCoupe

Banned
Feb 17, 2004
606
0
0
Post Count City
Jul 24, 2005
#23
  • Jul 24, 2005
  • #23
Grn92LX said:
Lets do it!!

Whats your combo by the way? I didn't know you had a 331.
Click to expand...

It's a quick street combo:
'89 low option ex-SSP notch
3062lb with me
DSS 331 (5.315) lvl 20
AFR185's 58cc
XE266HR w/1.6s
RPMII
Edel 70tb
75maf w/ CAI
30#/190lph
FRPP A/C Delete
130amp
MSD ignition
FRPP ceramics/Magna catted mid and catback
All tree-friendly stuff
DF Centerforce
T5Z
FRPP alum driveline
3.55 trak
Steeda FL SFC and STB
Steeda alum u/lca
Steeda Superlite springs w/ alum CC
Plus other misc. including a bottle, but maybe not
 

_jb_

New Member
Mar 4, 2004
808
0
0
Michigan, Berrien County
Jul 24, 2005
#24
  • Jul 24, 2005
  • #24
Grn92LX said:
My 347 with the 5.315" rods has the same "extra meat" as the 331 because I use 331 pistons Its the same part # if you look on coasthigh.com.


If you were gonna sell the 165's for different afr's get 205's. Even though the 165's are a bit small, they'll still make good power especially with a charger. To make a small head make big power, you'll need a good custom cam as valve timing will be critical.

I'd do at least a 347 since its a dart block. 3.40 stroke for sure, you pick the bore size.
Click to expand...

Won't 205s be to big?
 

MeanMussy

Founding Member
May 25, 2000
581
0
17
Louisville, KY
Jul 24, 2005
#25
  • Jul 24, 2005
  • #25
the 165s will be fine on that motor. your power will come on a little sooner, and you'll loose a little more on the top end vs. the 185s, but you'll be fine.

The 331 will have a slightly better rod ration vs. the 347 (reduced side loading). I believe the 331 ratio is as close to the stock 302 ratio as you can get w/ a stroker. but unless you are really worried about side loading, I wouldn't let it change your preference.

Generally speaking, the 331s will rev a little higher, and the 347s will make a little more low end TQ.

But, in the broad view of things, they're the same motor. If you're looking for a brute force build up, go w/ the extra cubes. If you want to get nick picky about it, do your research and pick the mill that best fits your objectives for the motor.
 

MeanMussy

Founding Member
May 25, 2000
581
0
17
Louisville, KY
Jul 24, 2005
#26
  • Jul 24, 2005
  • #26
_jb_ said:
Won't 205s be to big?
Click to expand...
205s will let it scream up top.. but it will make it a little more gutless in the first couple thousand rpms vs. the higher air velocities of the smaller heads.
 

Grn92LX

Fidanza Man!
Founding Member
Jan 14, 2001
6,819
64
129
New York
Jul 24, 2005
#27
  • Jul 24, 2005
  • #27
_jb_ said:
Won't 205s be to big?
Click to expand...

For a supercharged dart block stroker, no.

Generally speaking, the 331s will rev a little higher, and the 347s will make a little more low end TQ.
Click to expand...

Not true at all. The parts you choose for your stroker engine are what ALLOW it to rev. Case in point, look at my 347 and copcoupes 331. Mine will rev higher. Probably easily 1000 rpm's of useable power. Why? Well, because I CHOSE parts to allow me to make power up top and rev where as he chose a milder camshaft. His will probably make better power under 2500. My cam is designed with a 3200-6400 rpm band (which is what I wanted). Figure a 6600 or so shift point for optimal track times.
 

MeanMussy

Founding Member
May 25, 2000
581
0
17
Louisville, KY
Jul 24, 2005
#28
  • Jul 24, 2005
  • #28
"generally speaking"... as in, this is not ALWAYS the case
 

89CopCoupe

Banned
Feb 17, 2004
606
0
0
Post Count City
Jul 25, 2005
#29
  • Jul 25, 2005
  • #29
A big factor in turning high r's is keeping the valvetrain operating effectively at higher engine speeds ... a valvetrain that stays in check will keep the bottom end held together better ... floating valves or improper detonation will destroy the rotating assembly. Based on this a 347 and 331 are equal participants.

The use of a longer rod helps to negate side loads on all rotating assembly pieces as well. Also a crank with a shorter throw will experience less stress. Based on these factors a 331 can be built to spin more rpms than a 347 when confined within a 8.2" deck height block.
 
Prev
  • 1
  • 2
First Prev 2 of 2
You must log in or register to reply here.

Similar threads

  • Locked
Engine Might have to get a Dart block but don't want to and if I do, then 363 instead of 331. Thoughts on what I've already bought so far.......
  • from6to8
  • Jul 8, 2025
  • Fox 5.0 Mustang Tech
Replies
2
Views
412
Fox 5.0 Mustang Tech Jul 8, 2025
Noobz347
Progress Thread Progress Thread- From6to8's 1994 Cobra Supercharger install
  • from6to8
  • Sep 25, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 20 21 22
Replies
420
Views
9K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- May 6, 2026
from6to8
Might have to get a Dart block but don't want to and if I do, then 363 instead of 331. Thoughts on what I've already bought so far.......
  • from6to8
  • Jul 8, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 2 3
Replies
52
Views
2K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jul 9, 2025
from6to8
0
V6 to V8 Swap info
  • 02_2v_Curtis
  • Jan 11, 2026
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
0
Views
580
1996 - 2004 SN95 Mustang -General/Talk- Jan 11, 2026
02_2v_Curtis
0
Which one of these 3 intakes make the most sense for my 331 combo
  • from6to8
  • Jul 25, 2024
  • 1994 - 1995 Specific Tech
Replies
7
Views
2K
1994 - 1995 Specific Tech Jul 26, 2024
AeroCoupe
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?