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

Looking at a 331 this monday, wanted some pointers

  • Thread starter Thread starter SadbutTrue
  • Start date Start date Mar 28, 2008

SadbutTrue

Founding Member
May 1, 2002
2,390
4
49
Granada Hills, California
Mar 28, 2008
#1
  • Mar 28, 2008
  • #1
When I got my 66 coupe aligned last week, the shop had an ad posted for a 331 stroker engine for sale. I contacted the guy and it’s a later-model roller engine, with a (currently) unknown ford racing/SVO cam, stock heads from whatever engine it came off of, a forged crank, hypereutectic rods/pistons, and a performer intake. In addition to the cam specs, the guy doesn’t know what the compression is or much about the internals. Its currently sitting in a shop near where I work, where it was built. The engine was last installed in a 68 galaxie and was equipped with a carb.

I was wondering a few things about the heads & other engine specs and figure that this forum is the best place to hear these details. I was going to ask the shop its sitting at to remove a head so I can see what shape the bores are and see if the pistons have valve reliefs etc. My questions are...

1) How can I tell if its equipped with GT40s or E7 (or other late model 5.0 heads)?

2) What size combustion chambers did these heads come with (he doesn’t know the compression ratio so I might have to calculate it)?

3) Is there an easy & roughly accurate way to guess the cam’s specs (the shop is looking up the specs, but in the event they can’t find them)?

4) I have a 60s style radiator (as far as inlet/outlet position goes)… does anyone know the most cost effective pulley setup would be that would work with my radiator? I’ve heard serpentine setups, reverse-rotation water pumps, and a number of other things mentioned… what are my options?

5) Is there a difference between Ford Racing and SVO cams? I frequently hear about Ford Racing 'letter-series cams', but have never heard of an SVO cam (which is what the guy said it had in it).

6) And in general, what else should I be looking for and/or be wary of?

Thanks!
 

BK_CAULEY

it's built for speed not longevity, woman
Dec 26, 2006
0
10
49
Thomasville, ga
Mar 28, 2008
#2
  • Mar 28, 2008
  • #2
1) How can I tell if its equipped with GT40s or E7 (or other late model 5.0 heads)?

they have GT on the outside of the headon the corners near the lower head bolts.

2) What size combustion chambers did these heads come with (he doesn’t know the compression ratio so I might have to calculate it)?

Aluminum gt40's can be either ~64 or 58cc
Iron factory Cobra GT40's are ~64cc
Exploder GT40's are ~66cc
Exploder GT40P's are ~58-59


3) Is there an easy & roughly accurate way to guess the cam’s specs (the shop is looking up the specs, but in the event they can’t find them)?

have to know what cam it is. pull the timing cover and cahin and it will say B,E,F,X on the end of it

4) I have a 60s style radiator (as far as inlet/outlet position goes)… does anyone know the most cost effective pulley setup would be that would work with my radiator? I’ve heard serpentine setups, reverse-rotation water pumps, and a number of other things mentioned… what are my options?

a factory 87-93 setup should work fine

5) Is there a difference between Ford Racing and SVO cams? I frequently hear about Ford Racing 'letter-series cams', but have never heard of an SVO cam (which is what the guy said it had in it).

same things

6) And in general, what else should I be looking for and/or be wary of?

you should be wary of the crappy hypertectics. factory forged or aftermarket forged pistons are way stronger. if you dont plan on abusing it you should be ok.
 

2000xp8

SN Certified Technician
Aug 8, 2003
8,047
1,637
194
NJ
Mar 28, 2008
#3
  • Mar 28, 2008
  • #3
Used performance or used rebuilt engines are always high risk. Unless you know the owner personally or it's built with an aftermarket race block i'd steer clear of it.
The way i see it, it's probably a low budget engine anyway, or else he wouldn't of put mediocre parts on the top half.

I'd rather save up and have an engine built your way, elminates all the variables and will give you peace of mind when you fire it up.
 

Black1987Stang

Active Member
Aug 22, 2004
1,422
0
37
Jersey Shore
Mar 29, 2008
#4
  • Mar 29, 2008
  • #4
2000xp8 said:
Used performance or used rebuilt engines are always high risk. Unless you know the owner personally or it's built with an aftermarket race block i'd steer clear of it.
The way i see it, it's probably a low budget engine anyway, or else he wouldn't of put mediocre parts on the top half.

I'd rather save up and have an engine built your way, elminates all the variables and will give you peace of mind when you fire it up.
Click to expand...


I just picked up a complete 331 ALL FORGED shortblock with Trickflow stage 2 (for sale) cam, chain, timing cover, and balancer for 900 bucks, lowish miles, I pulled all the bearings and they all looked good......I guess I got one of those few good deals

How much is this guy asking for it?
 

2000xp8

SN Certified Technician
Aug 8, 2003
8,047
1,637
194
NJ
Mar 29, 2008
#5
  • Mar 29, 2008
  • #5
Just because the bearings aren't worn, doesn't mean all the tolerences are right, or it was balanced correctly.
Not saying you got a bad shortblock by any means, but you won't truely know until you run it for a few thousand miles.

Not sure what the price is now, but a cobra shorblock (stock 302) with B cam used to be only $1200, and that was with a warranty. I'd buy one of those before i'd buy a used engine that i didn't know 100% the history of.
 

BaBysARM

Founding Member
May 9, 2002
161
0
0
Hickory, NC
Mar 30, 2008
#6
  • Mar 30, 2008
  • #6
how much is he asking for the 331....sounds like he did use alot of cheap parts. Unless he is almost giving it away then steer clear of it.
 
You must log in or register to reply here.

Similar threads

Engine Suggestions on an engine rebuild. Stock cam/GT40Ps or aftermarket on both for a fun weekend driver?
  • MadSquirrelTech
  • Apr 28, 2026
  • Fox 5.0 Mustang Tech
  • 2
Replies
23
Views
968
Fox 5.0 Mustang Tech May 7, 2026
MadSquirrelTech
S
Fuel ‘88 GT Runs Rich Cold — Fixes Itself When I Unplug Sensors (ECT, MAF, O2, etc.)
  • Sufarry
  • Nov 6, 2025
  • Fox 5.0 Mustang Tech
Replies
12
Views
952
Fox 5.0 Mustang Tech Nov 9, 2025
Mustang5L5
Engine Pushrod Length?
  • foxbodyclark
  • Jan 25, 2025
  • Fox 5.0 Mustang Tech
Replies
1
Views
374
Fox 5.0 Mustang Tech Jan 25, 2025
limp
Progress Thread Progress Thread- From6to8's 95 GT/Saleen Supercharged 331 install
  • from6to8
  • Mar 22, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 2
Replies
24
Views
1K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- May 6, 2026
from6to8
Need some camshaft guru advice on power loss from supercharger to nitrous
  • TTSaleen
  • Dec 1, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
18
Views
781
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Dec 29, 2025
revhead347
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?