71-73 Swag

  • New T-Shirt Design (Also coffee mugs and posters!) – read more!
  • Mach 1 Key Tags available (almost gone!) – read more
  • Convertible Key Tags available (limited supply) – read more
  • Coupe Key Tags available (only a few left) – read more


Weekly Fun Question for Regular Members!
Back to Member's Index
Main WFQ Index
Winner's List
Remember, all replies in this thread are moderated so you will not see your post after you click submit!

Question Answer Winner
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Weekly Fun Question for 7-16-2011
cobra3073

*
Call Me a Cab
Joined: Jul 2010
Posts: 2,904

Reputation: 49

Region: South
Location: Memphis, TN
Custom User Image: [Image: TNsuprmod.png]
#1
Weekly Fun Question for 7-16-2011
Good Day:

The Weekly Fun Question (WFQ) is an exercise to give "General" Members the opportunity to test their knowledge on information relative to the '71 - '73 Mustangs.

It is also designed to allow the same members the chance to "win" a nice #1 Icon added to their profile when they are the first to provide the desired response. If a general member "wins" on three (3) separate occasions, the member will have his/her membership (a $25.00 value) paid for a VIP subscription.

Please note when you respond to this post, your "answer" will not appear until the end of the current contest (usually at approximately 7:00 P.M. {CST}) the following Monday when the thread is transferred to the "Archives" Forum. Today's contest will end at approximately 7:00 P.M. on Monday, July 18, 2011.

While VIP members can also "play", their reward is "bragging rights" amongst their peers on the VIP Forum. General members are NOT competing against VIP members in this exercise. VIP members have their very own periodic "contest" which has an even more substantive awardSmile.


The problem for this week is on our honored 351Cleveland Engine.

All things considered the same (stock block and rotating assembly) which version of the stock 351 Cleveland Cylinder Heads would provide the highest compression ratio on a given block? The acceptable response will include the identity of the head, the year(s) of manufacture and an explanation as to why.

Good Luck!

BT
Considering the parameters of the question, i.e. stock rotating assemblies and blocks, the acceptable response actually comes down to the volume of the stock cylinder heads. The smaller the combustion chamber, the higher the compression ratio for a given application. With that in mind, the 1970-1971 351 4V had the smallest chamber at 62.8 cc during the production of the Cleveland engines.

As an aside, the Boss 351 heads (which a couple of you chose) had a head volume of 66.1cc which equates to a 11.7 compression ratio when used with the Boss rotating assembly. If the '70-'71 heads are used with the Boss 351 rotating assembly, the compression ratio would be approximately 12.3.
None

Do the RIGHT thing.
07-16-2011, 12:00 PM
  Find   Reply


Comments
#2
Here is my answer/guess

1971 R-code (Boss 351)
The Boss 351 is a high-performance variant available only in the 1971 Boss 351 Mustang. Rated at around 330 hp (246 kW), it was fitted with a four-barrel Autolite spreadbore carburetor, an aluminum intake manifold, and aluminum valve covers. It had four-bolt main block/caps and a premium crankshaft, constructed from high-strength nodular iron. The cylinder head was modified for better airflow and solid lifters. The forged connecting rods were shot-peened and magnafluxed for strength, and used stronger bolts/nuts. Forged domed pistons gave a 11.3:1 nominal (11.1:1 advertised) compression ratio.

Head = Boss 351
Chamber =Closed. Large64.6-67.6ccsize

Port= Large

Intake
valve=2.19"

Exhaust
valve= 1.71"

Application =1971 Boss 351

Part number= D1ZE-B
4-bolt Mains 4-bolt main bearing caps are used to support higher horsepower and continued high speed operation.
These are found on:


R-code Boss 351, 1971R-code 351 HO, 1972
Q-code 351 CJ, 1971-73
While the 4-bolt main caps are found on only some of the 351C-4V engines, all 351C blocks are cast with provisions to accept the caps. The registration saddle is machined the same wide size as the 4-bolt engines. The supporting bulkheads are the same as the 2-bolt blocks, allowing the extra holes to be drilled and tapped.

  Reply
#3
All things being equal, the Australian 302 Cleveland heads built from 1972 - 1985 would give the highest compression. Those heads bolt right onto a stock American 351C block; but since the Australians reduced the stroke of the 351C from 3.5 to 3.0 inches and increased the connecting rod length from 5.780" to 6.030, they redesigned the heads with a smaller combustion chamber(from 72cc to 58cc), to compensate for the reduced stroke of the engine.
If you were bolt these heads to a regular unmodified 351C block you might increase the compression ratio beyond a safe level for regular pump fuel.
  Reply
#4
1971 Boss 351C. Closed chamber heads allowed for higher compression. I believe these had smaller chamberts than the M codes made in 70 and 71

'Mike'
73 Convertible - 351C/4V CC heads/4bolt/forged flat tops/comp 270/rhodes/mallory unilite/tri-power/hookers/glasspacks/c6/3.50 limited slip/Gear Vendors/Global West sub frames, strut rods and shelby style traction bars/ Rear sway bar/tilt steering (not original)

Pics of modifications included in:
  Reply
#5
That would be the 4V poly-angle quench head made in 1970 until May 1971.
They were closed chamber.

[Image: 1_11_11_13_11_50_27.png]
  Reply
#6
1970 300 hp... smallest combustion chambers.

Jeff T.

Low buck, touring style, '73 Convertible "rolling restoration", 351c, 2v heads with a shave and a haircut, Performer intake, Holley 650(ish), roller rockers, screw in studs, guideplates, stainless valves, Duraspark / Motorsports MSD, T-5 conversion. 1-1/8" front, 3/4" rear swaybars KYB shocks and some home brewed subframe connectors. Future plans; JGC steering box, Cobra brakes and... paint, interior, etc.

When I die I want to die like grandpa, peacefully in my sleep... not screaming, like his passenger.

[Image: 1_12_09_14_10_15_11.png]
  Reply
#7
Closed chamber heads with a chamber volume of 61-64cc (62,8cc). The smal chamber volume push the compresion up. The smal chamber 4v heads are only [/quote]produced from 70 to 71.

D0AE-G
D0AE-H
D0AE-M
D0AE-N
D0AE-R

[Image: t5Banner.jpg]
  Reply
#8
The '71 M code heads. Since so many others have already answered I'll skip looking up the part numbers. They were made in '70-'71.

[Image: 386_07_10_13_5_58_42.jpeg]
My Mustangs:
71 M-code Mach 1, Medium Blue/White Sport, 4R70W, 3L50, Factory Ram Air.
72 Q-code Mach 1, Pewter/Black Sport, 4-spd, 3L25.
73 F-code Convertible, Planned: color TBD/Black top/White Int., 351C, 5-spd, 3L50.
65 Convertible, Britney Blue/White/White, more modified than original.
05 Convertible, Legend Lime/Tan/Tan, future classic??
  Reply
#9
Good Day!

We did not have an acceptance response posted to the thread from the "General Membership" for this week's Weekly Fun Question.

To recap, the question is:

All things considered the same (stock block and rotating assembly) which version of the stock 351 Cleveland Cylinder Heads would provide the highest compression ratio on a given block? The acceptable response will include the identity of the head, the year(s) of manufacture and an explanation as to why.


Considering the parameters of the question, i.e. stock rotating assemblies and blocks, the acceptable response actually comes down to the volume of the stock cylinder heads. The smaller the combustion chamber, the higher the compression ratio for a given application. With that in mind, the 1970-1971 351 4V had the smallest chamber at 62.8 cc during the production of the Cleveland engines.

As an aside, the Boss 351 heads (which a couple of you chose) had a head volume of 66.1cc which equates to a 11.7 compression ratio when used with the Boss rotating assembly. If the '70-'71 heads are used with the Boss 351 rotating assembly, the compression ratio would be approximately 12.3.

While we did not have a winner from the "General Membership", there were several members from the VIP Forum who provided an acceptable response. The first to reply to the post was "goodnigh" who has won bragging rights for this week's question.

It should also be noted that I had a correct response received at my email address from a general member but since it was not posted to the thread I had to discount the response. Please note that in order to ensure transparency, it is imperative that the responses be posted to the thread.

CONGRATULATION, goodnigh as your have "bragging rights" on the VIP Forum for this week.

Source: "Ford V8 Engines" by Tom Monroe (among others).

BT

Do the RIGHT thing.
  Reply
#10
My apologies to everyone!

I thought I had cleared the above post this past Monday to transfer this thread to the Archive Section which allows everyone to review the results but apparently I did not.

Sorry for any inconvenience.

BT


Do the RIGHT thing.
  Reply



Possibly Related Threads...
Thread Author Replies Views Last Post
  Weekly Fun Question for 9/21/2013 Don65Stang 4 827 04-06-2018, 11:41 AM
Last Post: Boss1Ray
  Weekly Fun Question for May 17, 2014 cobra3073 10 1,921 05-16-2016, 01:27 PM
Last Post: timachone
  Weekly Fun Question for May 10, 2014 cobra3073 12 1,185 05-16-2014, 03:35 AM
Last Post: 1972MustangSVH
  Weekly Fun Question for May 3, 2014 cobra3073 15 1,187 05-08-2014, 06:12 PM
Last Post: goodnigh
  Weekly Fun Question for April 19, 2014 cobra3073 3 648 04-21-2014, 08:53 PM
Last Post: arnie427
  Weekly Fun Question for April 12, 2014 cobra3073 6 735 04-14-2014, 11:03 PM
Last Post: caspianwendell
  Weekly Fun Question for April 5, 2014 cobra3073 9 981 04-10-2014, 04:52 PM
Last Post: OLE PONY
  Weekly Fun Question for March 29, 2014 cobra3073 7 859 04-01-2014, 06:07 AM
Last Post: CZ-75


Trivia Forum
Powered By XThreads