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Author Topic:   71 Cougar with 351C & FMX-Need Advice

Posts: 1
From: Greeley, CO,USA
Registered: Aug 2001

posted 08-31-2001 06:42 AM     Click Here to See the Profile for jwchatm   Click Here to Email jwchatm     Edit/Delete Message   Reply w/Quote
I have a 71 cougar with 351C and FMX tranny. I am swapping the 2V openchamber heads for a set of 4V closed chamber Quench heads. I have converted to 1.73/3/8" Harland roller rockers complete with crane conversion guide plates and single piece chromemoly pushrods. Unexpectedly my engine came with factory cast flattops but I am going with TRW Forged +.030 flattops in case I want it run NOS in the future. We will be installing a shiftkit and 3000-3500rpm stall. Cam is a Lunati Bracket Master II specs are 290/300 duration and .563 lift with wild lope.I am running headers and 2.5" exhaust cuz my exhaust shop can't bend 3". I am also using uncapable warlocks.Is there a big increas in HP when going fron 2.5" to 3" exhaust? I think (am not sure) it is running 3.00:1 gear ratio...we were thinking of bumping gear ratio to 3.73 or 4.11, however I would still like to retain decent streetablity. Also what carb do I want and how do I want it jetted. Any recommendations would be most apreciated. Is it a good idea to run ChromeMoly rings? and also, the machine shop used umbrella seals in the heads instead of o-ring seals after the this a good idea?
I am also using an Offen. single plane aluminum intake. Also have a 2V to 4V Holley Street Dominator for sale.

[This message has been edited by jwchatm (edited 08-31-2001).]

[This message has been edited by jwchatm (edited 08-31-2001).]

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Posts: 6563
From: ...a wonderful place to be.... orange county... NC!!!! M&M member #92 .... a blue-oval GRRL-deluxe.....
Registered: Jun 99

posted 08-31-2001 08:35 AM     Click Here to See the Profile for kwazykat   Click Here to Email kwazykat     Edit/Delete Message   Reply w/Quote
first of all, welcome to M&M...and secondly it is great to add another cat to the pack...

although i cannot respond to your question, we have some incredibly knowledgable cleveland folks here.....

keep checking back.... i am sure someone will come along soon and help you out!!


the original GRRL...
ford true-blue-blood
62 fairlane 500 sports coupe, she will be my street-legal-drag-racing-machine (CHIKCOOP)
66 fairlane 500 4-door (waiting for a new home...maybe)
67 fairlane 500 ranchero (SPUNKY67)
carolina cougar club
cougar club of america
67 cougar: dan gurney special (KWAZYKAT)
69 cougar standard convertible (KATSMEOW)
84 F150 (TRUKGRRL)
the only polish on my nails is "ford grease black"

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Posts: 332
From: Oklahoma City, Oklahoma
Registered: Nov 2000

posted 08-31-2001 09:03 AM     Click Here to See the Profile for MrXerox   Click Here to Email MrXerox     Edit/Delete Message   Reply w/Quote
I have a VERY similar combo to the one you are about to build and have made some of the mistakes you are about to make already You will have to put gears in that car to make any streetable power with that motor. I have 3.90's in mine for better streetability but you could get away with 4.11's with a taller tire. As far as the cam is concerned, what you think is going to have a "wild lope" in a Cleveland might not be what you expect. I have a solid roller 244 @.050 .623/.623 in mine and it idles like a street car. I would suggest you go with a solid lifter cam with around the same duration or a little higher than mine with a 110 lobe sep. If you go with a 108 or lower you will be building too much cylinder pressure and will have to run octane booster every time you fill up the car (been there, done that) Your 2.5 exhaust should be fine but your tranny is going to cost you gobs of power and dont know how long it will hold up to the power you are wanting to produce. I as well as everyone else on this board will recommend you swap it out for a good built C-4 (they take approx 35 less HP to turn and are plenty strong) Lose the Offen. intake the ONLY way to go with a Cleveland 4V is a Torker II, Weiand X-Cellerator or if you can find one the Holley Strip Dominator is the #1 choice. As far as the carb goes, I found that a Holley 750DP works wonders for mine...Tried an 850 and never could get it to work out for me...good luck and happy spending!

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Posts: 800
From: Connersville, IN
Registered: Jul 2001

posted 08-31-2001 10:09 AM     Click Here to See the Profile for clevelandstyle     Edit/Delete Message   Reply w/Quote
I'm with MrXerox. Chuck the FMX. Get more cam, get more gear, get a better intake, and get a 750DP or bigger.
If I remember right, the '71 Cougers are heavy. Your gonna need low gears.
If you don't do these things now, you end up doing them later.

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Posts: 37258
From: Saco, Maine
Registered: May 99

posted 08-31-2001 03:31 PM     Click Here to See the Profile for SteveLaRiviere   Click Here to Email SteveLaRiviere     Edit/Delete Message   Reply w/Quote
You really do need lower gears. 4.11s or 4.30s, even 4.56s if you can stand the revs.

I used the Crane conversion kit, and I really don't recommend it. It's a light-duty band-aid solution. My studs loosened up on me twice and that was in a F-150 that never went over 6000.

Machining your heads for 7/16" studs and guide plates is a good investment, IMHO.

'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
Keep your driveway ALL Ford!!!

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kid vishus

Posts: 5248
From: middle of NC
Registered: Oct 2000

posted 08-31-2001 04:49 PM     Click Here to See the Profile for kid vishus   Click Here to Email kid vishus     Edit/Delete Message   Reply w/Quote
That cam is ground so it will lope at idle, not a real radicall lope, but it will definately be noticable.

Screw in studs is the correct way to put adjustable rockers on. And, for one piece pushrods, buy some good 3/8" .060 or .065 wall. They are lighter than 5/16 .080 wall, and stronger.

On my street car with a mild cleveland,(my version of mild is slightly warpped ) I used to run it with 2.5" pipes into 3 chamber flowdisasters. It ran absolutely no faster with them off, it just made more noise.

Also, I have yet to take apart a 2v cleveland that didnt have flattops in it. And for a cast piston, they are a good one, and tuff. But not near as tuff as the forged you now have.

Yep, ditch the FMX.

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Gary Ferringer

Posts: 59
From: Kennerdell,Pa.
Registered: Feb 2001

posted 08-31-2001 06:45 PM     Click Here to See the Profile for Gary Ferringer   Click Here to Email Gary Ferringer     Edit/Delete Message   Reply w/Quote
I used that same camshaft years ago. It worked very well, one word of advice though, shift the thing at about 5800, the power falls of a cliff at 6000. I had about 14 inches of vacuum at idle. It would have been quite streetable, if I had driven it on the street.

In my opinion, you should go with a dual plane intake, I used an old F351 Edelbrock on mine. Experiment with different heights of OPEN spacers. Also, don't get too crazy with the carburetor. Maybe a 650, or a 700. If you go with a 750, use a vacuum secondary carb with a black spring. Start with the factory jetting, and adjust accordingly as far as what gets the car down the strip quicker, don't waste your time with seat of the pants tuning, get some real ET's and MPH' s at a drag strip. Also, keep your power valve. Use a 6.5 in the primary.

With your heavy car, and the gears that you are running, the single plane intakes will not work well at all. I experimented with a Weiand excellerator with this cam, and found that it worked OK, but I had 4.56 gears, and a 3500 convertor. The F351 had better 60 foots. I also didn't gain any RPM with the Weiand. There is nothing wrong with the Offenhauser intake, In fact I would choose it over the Weiand because of the fact that it will keep the velocity up higher,and the runners all converge toward the plenum a little better. I am talking about the Port O Sonic here. Don't even consider a Strip Dominator for this combination, unless you don't want any low end at all. I never cared for the Torkers personally.

The 2 1/2 inch exhaust is good, don't go any bigger. I don't know what headers you are using, but don't make the mistake of putting 1 7/8 primaries on it. 1 3/4 should be plenty. And 1 5/8 would be better in my opinion, but you usually don't find them that small for a Cleveland. The length needs to be around 38 to 40 inches. Keep the collectors to a absolute maximum of 3 inches in diameter.

I have never fallen in with the bigger is better crowd when it comes to setting up an engine. For the RPM range that this cam will work in (about 2000 to 6000 max) my recommendations will get you down the drag strip quicker. If you want to go with bigger cams and such, then you will have to re -think everything, and streetability falls off rather quickly.

I agree about getting rid of the FMX, if for no other reason than it will be harder to find parts for it. A C4 will work fine.

Go with the 4.11 gears at least.

The umbrella seals will be fine.

Why not use Moly rings? I use them in everything anymore. Just make sure that the bore finish is correct.

My combination ran 7.50's in the 1/8 mile with pretty much what I told you to do,in a 3300 pound '68 Mustang with me in it, stock leaf springs, and 4 wheel drum brakes included. It idled at about 800 or 900 RPM, and like I said had about 14 inches of vacuum at idle.

'85 Capri
Cleveland powered
6.95 1/8th
@94 1/2 MPH
1.49 60 ft.

[This message has been edited by Gary Ferringer (edited 08-31-2001).]

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