[1973Coug]

Hello All:

I am very close to purchasing a 73 Cougar. Hope to have it in the garage by Monday. Anyways, I have a numerous amount of questions to ask you experienced Cougar owners.
It is a 1973 Cougar with a 351C 2barrell. It has 101,000 miles on it. It is all original. Not sure of the transmission yet, FMX or C6. My goals with it are to add some performance. Nothing crazy, but want something to on occasion bracket race and have some decent qtr mile times. Only looking for say high 14's. The horsepower on the engine looks to be at around 160. I plan to look at it again and ask more questions. What will it take to meet my goals? Was thinking the usual; better inhale and exhale. What qtr mile times can i expect with a single plenum intake, holley 750 CFM, mild hydraulic cam and performance dual exhaust?

Also, if anyone knows the length of a 73 please let me know. Need to make sure it will fit in the garage.

Thanks all for the help

 

[woodsnake]

Go ahead and add your location to your profile, there may be another "C" fan nearby....Also, the search is your friend...Lots of builds have been planned here, some results better than others. A new rear end gear set, say a 3.50, 2 1/2 inch exhaust, ~.500 inch lift cam, and a 650 Holley will make for a fun car.

 

[Cougrrcj]

With a heavy car like a '73 (please note that I have four of them!), you are really better served with a dual plane intake like a Performer, or maybe even a Performer RPM Air Gap. Leave the single-plane intakes to all-out race cars because they're 'soggy' (not good for crisp throttle response) on the street.

Stick to a 600-650cfm vacuum secondary carb, too. I tried 750s on both of my CJ cars and actually went slower! One of those Holley 660 Street Avenger carbs would be just about right.

Cam - I have an old Crane Econopower 260 (.493/.510, 260/272 adv dur) in BetaCat and along with a stock 4V intake, cast iron exhaust manifolds, factory duals, and 3.70 gears, that car is down to 14.40s @ 94mph. That cam is now one of the generic grinds that Summit sells for $130 with lifters... Can use stock-type valvesprings, too! (But use new ones)

Rear gears - chances are your car has a 2.75 open rear end. CJ cars got 3.25s from the factory. Even when BetaCat still had 3.25 gears (and everything else the same as above), my ETs were 14.80s.

Exhaust - 4V cars got 2-1/4" exhaust, whereas 2V cars got 2". Either buy a set of stock replacement pipes from Mustangs Unlimited, or take it to a custom muffler shop and have something bent up to your choosing. The MU tailpipes are a bit short, so they either need to be extended or have something else made.

 

[cardoctor]

It's 200 inches overall bumper to bumper. I have a 73 351C 2v FMX, it has been upgraded to a 4bbl but still has 2bbl heads, also headers and a 3.25 traction lock. I'm not happy with the performance, running a edelbrock 650 performer. I would say being old school and used to horsepower it's missing compression, a poor 8 to 1 factory, I would bet the car is turning mid 15 seconds if I took it to the track. The heads are good just wish I could get aluminum heads or a set of aussie 2v to raise compression. I do have a 429 I want to drop in, that would help LOL.

My last hot rod was a 1967 cutlass 330 factory 320 horse, I switched it to a 4 speed, installed a chevy 12 bolt posi 331 ratio, turned 13.2 seconds at 98 MPH engine had 10 1/2 to 1 compression was stock except for aluminum intake and a 750 holley vac secondaries, factory duals no headers.

 

[Cougrrcj]

All 351C-2Vs regardless of year are 9.5:1 compression, so there's no good reason to go higher on today's cheap regular unleaded gas. Heck, my 480hp 393W is only 9.4:1 compression, yet turns 13.06 @ 108 in a 4000-pound car!

A proper 'balanced' engine build - cam, converter, intake and exhaust selection - is essential to avoid poor performance. Cleveland heads and intake manifolds already have large intake runners capable of supporting lots of power. The problem is the exhaust side due to the C's crummy exhaust port design. Nothing that can't be overcome with proper cam selection, i.e. one with more lift and duration on the exhaust side. Stock 2Vs only had a .424/.424 lift cam. A CompCams 265DEH or XE262H would be a good modern choice. According to my Comp Cams CamQuest6 software, wither will yield around 340hp @ 5000rpm, and 390 lb/ft torque at 3500.

Again, considering the large ports (even 2Vs are big compared to the Brand X head ports) avoid going too big with either carb or camshaft selection to avoid a slow-moving intake charge. That's why a relatively short duration cam and a dual plane intake are preferred for street use.

Remember that from the factory, GT390 engines came with 600cfm vacuum secondary Holleys, and 428CJs used 'only' 735s! Neither of those were slouches!

 

[TommyK]

"All 351C-2Vs regardless of year are 9.5:1 compression, ..."

With all due respect I don't believe that is correct.

70 9.5:1
71 9.0:1
72 8.6:1
73 8.0:1

And these are the nominal specs. I bet if you measured a 73 it would be less than 8.0:1. If the OP is looking at a rebuild anyway, he would be well served by using flat tops to get the compression back closer to the 9.5:1 you recommend. Many more effective cam choices available at 9.5:1 than the anemic 8.0:1.

 

[Cougrrcj]

The book I have (and every 2V motor I've taken apart verifies this) says that all had 76cc heads and flat tops. so all were 9.5:1

4Vs were all over the map, since they have differing chamber sizes and also the dish pistons used in Q-code motors...

Also remember that starting in '72, the camshafts themselves were ground retarded 4* for emissions reasons.... Just another reason to trash the original cam and go aftermarket. 429/460s decided to index the timing set crank gear keyway 4* retarded.

 

[fomocofan]

I was not aware that the cams themself were retarded..I thought all post 71 engines were retarded 4 degrees at the crank gear...If that is true, couldnt you just use a multi-indexed gear and advance it 4 degrees and wake it up alittle w/o changing cams?

 

[Hawk1]

Yes you can use a multi-indexed cam gear to advance a cam that has been retarded. This was a common hop up for the 73 clevelands.

 

[Cougrrcj]

Fomocofan,

As I stated before, Clevelands retarded the actual cam itself. 429/460s used a retarded crank gear in the timing set. BUT the early 2V/4V factory cam was pretty winpy. A stock Q-code 4V replacement cam would be better, advanced 4* of course.

My wife's '70 Mach 1 - M-code 351C-4V/FMX/3.25s is only good for 15.0x in the quarter... and that's a much lighter car than a heavy '73! As I noted above, even a generic cheapie Summit .490/.510 cam really wakes these cars up. Good for stock valvesprings, too... but use new stock replacements!