Brought to you in part by:

M&M Restoration & Tool Supply Store

Great deals on auto restoration supplies!

.


NOTICE! The old Mustangsandmore.com is a read-only archive.
Currently the Search function is inoperative, but we are working on the problem.

Please join us at our NEW Mustangsandmore.com forums located at this location.
Please notice this is a brand new message board, and you must re-register to gain access.

  Mustangsandmore Forum Archive
  Ford Racing
  351C 2V/4V heads.......CFM vs. HP/Torque

Post New Topic  Post A Reply
profile | register | preferences | faq | search

next newest topic | next oldest topic
Author Topic:   351C 2V/4V heads.......CFM vs. HP/Torque
DutchD58
Gearhead

Posts: 142
From: West Milton, OH
Registered: Jul 2000

posted 11-25-2001 10:22 AM     Click Here to See the Profile for DutchD58        Reply w/Quote
For the last year or two I've been mulling over the approach for a street oriented Cleveland build-up for my Torino. For my own reasons, I favor the Cleveland over the Windsors or Big-blocks. I've also settled on building a stroker, probably a 393C. What I was still not sold on, however, was whether to use ported 2V or fairly stock 4V heads for my horsepower and torque goals (420-450 HP and maximum available torque from the combo) and to try and keep it under 6500 RPM's. It's no secret that the stock 2V heads offer better throttle response and torque down low and are good for about 350HP, but I could never find anything that could quantifiably tell me what the HP potential was for a set of properly set up 2V heads So, for a different perspective, I posted a question at another board that produced some interest and answers that you may find eye opening or re-assuring, depending on where you're coming from. I intentionally, initially, asked the question pertaining to a heads' flow as it relates to HP in such a way as to try and not bias the responses due to someone's preference for Windsor or Cleveland power, and was very pleased with the answers. As you sift through the debate (and it got a little heated), there's some good information, proven formulas and a few links that you may find useful in making a decision. I know it did for me!
Below are the links to the discussion and a few others that may be helpful, too.

Kevin

http://www.fordmuscle.com/boardpower/discussion.cgi?forum=1&discussion=4523

http://www.bgsoflex.com/auto.html

http://www.waldens.com/waldens/fmotorsp.htm

http://www.powerheads.com/ProductDetails.asp?product_id=6

mj
Journeyman

Posts: 3
From:
Registered: Nov 2001

posted 11-25-2001 12:58 PM     Click Here to See the Profile for mj        Reply w/Quote
for your heavy car i would use the aussies
but
if you have a few sets of closed chamber 4vs kickin around use them as it will be cheaper
cant remember if you are an auto guy, if so high stall is in your future
seems you are overthinking this street engine.

[This message has been edited by mj (edited 11-25-2001).]

badazzcougar
Gearhead

Posts: 132
From: Seattle
Registered: Oct 2001

posted 11-25-2001 06:54 PM     Click Here to See the Profile for badazzcougar        Reply w/Quote
How do the cleveland heads compare flow wise to say small block chevy heads or good factory windsor heads. the 2V and the 4v versions.

SteveLaRiviere
Administrator

Posts: 48752
From: Saco, Maine
Registered: May 99

posted 11-25-2001 07:12 PM     Click Here to See the Profile for SteveLaRiviere        Reply w/Quote
This should help. It's from the Dec. '99 Mustang & Fords magazine:


They have a mistake in their chart -- the exhaust valve for a 351 Cleveland 4V head is 1.71", not the 1.67" valve they have listed.
Also, the 351 Cleveland 2V valves are 2.04" intake and 1.65" exhaust.

'70 Mustang Mach 1 M code 351C 4V/FMX/3.25 open
'72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Lok
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
'97 Probe GTS 2.5L DOHC
My Photo Page
Christmas shopping? Why not use the Mustangsandmore.com Bookstore?

[This message has been edited by SteveLaRiviere (edited 11-25-2001).]

DutchD58
Gearhead

Posts: 142
From: West Milton, OH
Registered: Jul 2000

posted 11-25-2001 10:56 PM     Click Here to See the Profile for DutchD58        Reply w/Quote
badazz, the 2V heads (Aussie or American) will apparently equal or better the stock 4V heads, up to .500"-.550" lift when set-up with larger valves and ported. Couple that with the smaller ports' higher velocity (torque) and you get the best of both worlds, up to a certain point. The link to "Powerheads" below will give you an idea of what many have been able to typically achieve with a modified 2V head. With approximately 240 CFM @ .550" the 2V heads SHOULD be capable of supporting something around 490 HP. And that's N/A with no power adders!
mj, I will probably run the Aussies. While you'll NEVER hear me say "money is no object", since this is a long term investment for me I do expect to spend more than if it were just a basic re-build and warm-up. Yes, I'm gonna run a C-6 with an aftermarket torque converter and some steeper gears. I know a C-4 would be faster, but again, I'm building for the long haul. As far as overthinking it goes, I don't look at it that way at all, I just want as clear a picture as possible before I lay down any money.
Steve, do you have any of the older (late '70's- early '80's) SuperFord mags? I seem to recall some articles with flowbench comparisons between the 2V/4V heads, stock vs. ported. Used to have 'em, but that was at least 4 kids and two wives ago!

Kevin

http://www.powerheads.com/ProductDetails.asp?product_id=6

badazzcougar
Gearhead

Posts: 132
From: Seattle
Registered: Oct 2001

posted 11-25-2001 11:38 PM     Click Here to See the Profile for badazzcougar        Reply w/Quote
say I were to pick up a set of aussie heads for racing and had them cut for 4V valves. Ive got pop up pistons which would kick my compression up to 12.5 to one or so. How much power is that extra 2.5 points of comression going to give me? I assume I'd have to go to a wilder cam to take advantage of the extra compression. Or would I just be better off going with a set of quench 4 v heads?

Also I understand the 4V aussie heads were really on a 302 . Is that 302 crank available? Was it a cleveland based engine or windsor like the US? did it use 351 pistons and longer rods? Sounds like a screamer.

[This message has been edited by badazzcougar (edited 11-25-2001).]

Clevo377
Gearhead

Posts: 312
From: Blackburn, Victoria, Australia
Registered: Nov 2000

posted 11-26-2001 04:30 AM     Click Here to See the Profile for Clevo377        Reply w/Quote
I'd go with stock (or just cleaned up) 4V. Pick a mild (214/224) cam and 850 Holley and you'll make 400Hp at around 6000rpm, Thats what I did Stand on the gas down to 1800rpm and the tires lite up (with a stick shift and 3.5 rear)

Paul

mj
Journeyman

Posts: 3
From:
Registered: Nov 2001

posted 11-26-2001 02:43 PM     Click Here to See the Profile for mj        Reply w/Quote
I am no aussie expert, but the aussie didnt answer it

i understand the 302c to be a long rod short stroke with unique pistons in a 351c type block.

SteveLaRiviere
Administrator

Posts: 48752
From: Saco, Maine
Registered: May 99

posted 11-26-2001 06:21 PM     Click Here to See the Profile for SteveLaRiviere        Reply w/Quote
quote:
Originally posted by DutchD58:
Steve, do you have any of the older (late '70's- early '80's) SuperFord mags? I seem to recall some articles with flowbench comparisons between the 2V/4V heads, stock vs. ported. Used to have 'em, but that was at least 4 kids and two wives ago!

I may have, deep in my cave. I'd need a safari to go hunting for them...

------------------
'70 Mustang Mach 1 M code 351C 4V/FMX/3.25 open
'72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Lok
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
'97 Probe GTS 2.5L DOHC
My Photo Page
Christmas shopping? Why not use the Mustangsandmore.com Bookstore?

DutchD58
Gearhead

Posts: 142
From: West Milton, OH
Registered: Jul 2000

posted 11-26-2001 08:18 PM     Click Here to See the Profile for DutchD58        Reply w/Quote
badazz,
There are others here who could answer this better than me, but if you had a 400 HP, 10:1 motor and raised the CR to 12.5:1, with no other changes, I think that would be good for another 25 or so HP.
Kid Vishus (Rob) could probably tell you a great deal about the 2V heads in a race motor. I seem to recall he's gone as fast as 10.4 with a high compression motor running on alcohol, and spun it to well over 7000 RPM.

kevin

DutchD58
Gearhead

Posts: 142
From: West Milton, OH
Registered: Jul 2000

posted 11-26-2001 08:21 PM     Click Here to See the Profile for DutchD58        Reply w/Quote
quote:
Originally posted by SteveLaRiviere:
I may have, deep in my cave. I'd need a safari to go hunting for them...


Hey Steve,
I'd be more than happy to be your gunbearer on that one..........

kevin

futurattraction
Gearhead

Posts: 108
From: Iowa City, IA
Registered: Oct 2001

posted 11-26-2001 08:40 PM     Click Here to See the Profile for futurattraction        Reply w/Quote
badazz,
The Aussie 302C heads have a tighter chamber than our U.S. 4V quench heads. A guy on the 335 series board discovered that his pop up pistons interfered with the Aussie heads he got. As mj said, the Australian 302C was a 351C-based block with a 3-inch stroke crank and 6.03 rods. Scott

Clevo377
Gearhead

Posts: 312
From: Blackburn, Victoria, Australia
Registered: Nov 2000

posted 11-27-2001 01:48 AM     Click Here to See the Profile for Clevo377        Reply w/Quote
****** 302C *******
[email protected]
[email protected]
4" bore x 3" stroke
6.03" rods
9.4:1 CR
small port
58cc chamber
2.04/1.65 valves

Paul

Clevo377
Gearhead

Posts: 312
From: Blackburn, Victoria, Australia
Registered: Nov 2000

posted 11-27-2001 01:57 AM     Click Here to See the Profile for Clevo377        Reply w/Quote
Oh, 302 Cranks are VERY common here. Just recently threw one out (kept the heads though ) From what I know they're not that strong. Most people go for the 3.5" crank...more cubes.

Paul

All times are ET (US)

next newest topic | next oldest topic

Administrative Options: Close Topic | Archive/Move | Delete Topic
Post New Topic  Post A Reply
Hop to:

Contact Us | Mustangsandmore Front Page

Copyright 2006, Steve LaRiviere. All Rights Reserved.


Ultimate Bulletin Board 5.47d

Amazon Honor System Click Here to Pay Learn More

[Build a free Mustangsandmore.ws Home Page!]

[Posting Pictures]

[About M&M][Members' Pics]

[M&M Conventions] [M&M Mug Shots] [Tech Articles]

[M&M Bookstore] [M&M Restoration & Tool Supply Store]