• 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
351C 4V. What to do for torque?
#1
So how does one make a high reving 4-V 351c have a good amount of low end torque? I'm out of my element with the 351 cleves.

351C recently rebuilt
Holley 700cfm DP (model 4778-2 1433).
Edelbrock TORKER 351 intake.
4V dot heads.
Reed Cam. See cam card below.
Hooker Super Comp Headers.

[Image: IMG00263-20110221-1121.jpg]

Apparently the previous owner wanted a rev happy, performance oriented engine and built it that way. Realistically I drive at less than 3500 rpm so I don't need a rev happy engine, I need one with some low end grunt; preferably lots of low end grunt. Big Grin I'll be putting a Tremec 3550 5-spd behind it followed by 3.25 or 3.50 posi gears in the rear end.

help What's do I do to get there? Sell the current engine and start over? Swap out the intake for a Blue Thunder dual plane? Swap out the cam? Different headers?
Huh

[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.
65 Convertible, Britney Blue/White/White, more modified than original.
05 Convertible, Legend Lime/Tan/Tan, future classic??
  Reply
#2
IM RUNNING A BIG BLOCK, WELL MAYBE SOMEDAY NOW ITS ON THE ENGINE STAND. BUT I THOUGHT I FOUND A GOOD DEAL ON A 351C BUT IT FEEL THRU. ANYHOW I HAD STARTED RESEARCHING THEM AND FOUND THIS SITE, I HOPE YOU CAN FIND WHAT YOU NEED.
http://351cleveland.wetpaint.com/ GOOD HUNTING MY FRIEND
  Reply
#3
PAPPY HAROLD;13921 Wrote:IM RUNNING A BIG BLOCK, WELL MAYBE SOMEDAY NOW ITS ON THE ENGINE STAND. BUT I THOUGHT I FOUND A GOOD DEAL ON A 351C BUT IT FEEL THRU. ANYHOW I HAD STARTED RESEARCHING THEM AND FOUND THIS SITE, I HOPE YOU CAN FIND WHAT YOU NEED.
http://351cleveland.wetpaint.com/ GOOD HUNTING MY FRIEND

Yes, I think that is probably the best place to look... I've read the posts there but never registered. A little caution, you may wish to search the engine build posts because there is a ton of information that has been posted already... There are a couple guys on there that run Pantera's, and some engine builders like Mark McKeown and Tim Meyer.

I've got my Cleveland out and was going to rebuild for my pickup project. If you aren't set on the original heads, there are good aluminum heads available now, Trick Flow and CHI Aussie heads.
  Reply
#4
Stroke it for low end torque.

http://www.mre-books.com/biginch/biginch5.html
  Reply
#5
As you probably know, performance goals are primarily about 'trade offs." On the surface, your question seems relatively simple, BUT in reality it brings up other "issues."

Given the attributes of a particular cam, you can pretty well set up your rear end gears to take advantage of those attributes. There are mathematical formulas that will help you determine what rear end matches the power band of your camshaft. While that would probably be the easiest way to go, it has consequences in possibly higher gas usageSmile.

As tnfastbk said, stroking is also a viable approach but necessitates swapping out your rotating assembly which pretty much equates to a engine rebuild.

You could also change the camshaft to one with the attributes that matches your other components and your desired goals. Any of the major camshaft grinders can assist you with this.

Hope this helps.

BT

Do the RIGHT thing.
  Reply
#6
cobra3073;13993 Wrote:As you probably know, performance goals are primarily about 'trade offs." On the surface, your question seems relatively simple, BUT in reality it brings up other "issues."

Are we talking cars or women here? rofl

.
cobra3073;13993 Wrote:Given the attributes of a particular cam, you can pretty well set up your rear end gears to take advantage of those attributes. There are mathematical formulas that will help you determine what rear end matches the power band of your camshaft. While that would probably be the easiest way to go, it has consequences in possibly higher gas usageSmile.

As tnfastbk said, stroking is also a viable approach but necessitates swapping out your rotating assembly which pretty much equates to a engine rebuild.

You could also change the camshaft to one with the attributes that matches your other components and your desired goals. Any of the major camshaft grinders can assist you with this.

Good food for thought! I'm opting for the least expensive route so don't want to tear into a recently rebuilt engine, but a stroker would be awesome. I think I'll get the Tremec 3550 installed (once I find a set of pedals), drive it to see what it'll do and feels like, and then swap out the rear for a 9" posi...gears are yet to be determined - was thinking along the lines of a 3.25 to 3.50.




[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.
65 Convertible, Britney Blue/White/White, more modified than original.
05 Convertible, Legend Lime/Tan/Tan, future classic??
  Reply
#7
The 4v heads where made for high revs to start with. You do get more low end torque out of the 2v heads.

Eric


[Image: a58hgh.jpg]
DRIVE IT DON'T STORE IT!
  Reply
#8
If the cam was degreed in properly I don't see a problem with the cam. You could advance the cam 2-4 degrees and pick up low speed torque. The easiest, and probably the best thing to do is put a dual plane intake manifold on the engine. The Blue Thunder is a very good intake but more than you need and expensive. Find a 70 or early 71 stock 4V intake that is nearly square bore, as opposed to spread bore. You can make it truly square bore with a die grinder or sanding rolls. If you have room use a 1 inch 4 hole spacer under the carb. Set initial timing to 16 degrees BTDC, total advance at 36-38 degrees all in at 2800 RPM. The double pumper with 3.25-3.50 gears is questionable. Given the overdrive ratio in the Tremec you may want to consider 3.50 as the minimum gear ratio. This is not a computer controlled, VVT engine. If the rpm is too low at highway speeds you won't have the power or the mileage.

Good Luck,
Chuck
  Reply
Share Thread:  


Possibly Related Threads...
Thread Author Replies Views Last Post
  What to do to 351c 4v heads? scgamecock 45 1,369 11-19-2018, 09:27 PM
Last Post: jpaz
  351C decals and or markings (M code 1971) Ryunker 0 209 10-25-2018, 06:21 PM
Last Post: Ryunker
  351C Fuel Delivery Problem Rumblefish 20 638 10-16-2018, 01:39 PM
Last Post: Fabrice
  What does it take to stroke a 351c scgamecock 6 420 10-01-2018, 01:55 PM
Last Post: Hemikiller
  What externally will work on a 460 from a 351c scgamecock 15 537 09-29-2018, 01:57 PM
Last Post: 7173Vert
  71 vert dual exhaust, longtube header, 302 2V, reinforcement torque plate 1971V8 11 379 09-29-2018, 09:53 AM
Last Post: c9zx
  difference in 351C-2v heads Vinnie 27 1,165 09-23-2018, 06:49 AM
Last Post: Vinnie
  Increasing Power 73 351c Cobra Jet bytor2112 4 510 09-05-2018, 05:33 PM
Last Post: Carolina_Mountain_Mustangs



Users browsing this thread: 1 Guest(s)