Help me build my 351C-2V

[AustinCobra]

Fellow gear heads,

I’m restoring a 72 convertible with a 351c-2v. You’ll see lots of posts from me in the coming months concerning this project. Covering just about every aspect of the car. But since the motor has been torn down and is ready for the shop, I thought we’d get started with that.

First my goal:
A 71-73 Mustang convertible is quite possibly the heaviest mustang ever built. So I want to build a motor that will get her moven down the road with relative ease, and is reliable over time. I’m shooting for the 350hp mark, give or take a little, and more is always better. Since she is heavy, I’m sticking with the 2v which will allow the motor to produce its torque at a lower RPM.

Here are some topics of conversation for this thread.

Parts:

rebuild kits (I’ve been considering a Sealed Power rebuild kit)
Pistons and compression ratios
Intake
caberator
Cam
Valve job options
Headers
etcs​

Part Sources:

Summit
PAW
etc​

Concepts:

Popup pistons
3 angle valve jobs
intakes: Dual plain, air gap, etc
stall converters over stock​

Oh, and price is definitely an object here. I want a solid, reliable, powerful motor without braking the bank. And aside from the machining, I’ll be doing all the work.

I look forward to your advice.

Joe
Austin, TX

 

[AustinCobra]

Anyone...Anyone...Bueller...Bueller.

Ok, I just know there's a load of wisdom out there on this, and you're just dieing to share it with me, right!?

If this has been covered well in an older thread, please point me to it.

Thanks,

Joe
Austin, TX

 

['69Stang]

650 or 750 Holley with vacuum secondaries. It depends how sensitive you are to performance vs. over-carbing. A 750 should be fine, however. I’d run the Weiand intake manifold for 2v heads. An electronic ignition; Petronix should be fine if you want to keep the cost low. If you have the money, I’d get the heads ported, the 2v’s really need it. And get springs and hardware that are matched to the cam. You may want to consider titanium keepers if the budget allows and roller rockers. Regarding the cam, you’ll get more opinions than you’ll know what to do with, but I’d lean to a solid cam for the performance and better torque production, but that’s me. Work with someone you trust on the cam, don’t just call the Comp Cams help line. I’d try to get the compression to 10:1 for a little better torque production, though not much more if you are dealing with the open chamber heads. Mill the heads if you have to.
Regarding parts, I’d get a Summit kit with the TRW flat-top pistons, and upgrade the rod bolts to ARP fasteners, and Fel-Pro gaskets. Better rings are a small cost upgrade, also.

A 2500 stall converter probably makes sense. I’d like to see a 3.50 gear to get that vehicle moving quickly, also.

 

[dodgestang]

Is that 350 FWHP or RWHP.

If you are talking FW it won't be too difficult and you should still have a relatively reliable car. If you want that 350 at the rear wheel its a much larger undertaking and you might end up with a car that is marginally streetable given gas requirements and idle (very lopey) characteristics.

You don't need too much head work....have the chambers polished, have the exhasut ports polished, maybe a little porting. Get rid of the stock valves and install new stainless valve. 3 angle valve job would be your discretion. Get the heads milled and tapped for screw in studs so you can run a nice roller rocker set up. PIcking a cam is the hardest part....I ended up having a pro spec out a custom cam for my build, but that is a little pricey. You can make good power with one from the Extreme line over at comp. I like the weiand intake as well but I would recommend the 650 VC over the 750 VC for a daily drive and for the cubes...the ultmate choice depends alot on the total lift you get from the cam and the duration. 10:1 compression is a nice number to shoot for....as long as you plan to buy 91 octane or better all the time. Electronic ignition is a must, so petroniz for cheap, MSD for price but great.

 

[AustinCobra]

Awesome guys!! Thanks! And, yes, I was thinking a strong 350hp at the flywheel.

As for the intake, I was looking at the Weiand X-CELerator. Is this what you guys were speaking of?
http://www.holley.com/HiOctn/ProdLine/Products/AMS/AMSM/7516.html

On the carburetor, I've never been clear on the performance differences between a vacuum secondary and a mechanical secondary. Is it primarily throttle response?

Thanks!

 

[XeonTux]

I too will be looking to rebuild my 351 2V at some point (next winter maybe sooner?) Admittably I haven't looked real hard but I haven't seen kits for the 351c. I am trying to get an idea now of what $$ ballpark I'll be in and start planning my new cars future

'69stang recommended a summit kit but I don't see one there. The federal mogul kits they sell only lists a 351w, and the Summit branded kits have even less engine options. Am I missing something here?

 

[D.Hearne]

I also agree on what's been posted already, except for the compression ratio. I'd stick with the stock 9 to 1 ( flat tops with open chambers) I've seen a build up with 2 bbl heads that made 405 hp with this comp ratio and a dual plane intake, 750 Holley, and a little bigger cam than I'd go with. It was some thing with the lift in the .570-.590 range , I like to stick with a slightly smaller grind to cut down on machining costs, A Comp Cams 280H is a good choice.

 

[351LX]

I am in the middle of rebuilding a 351c 2 bbl motor myself.I have been wrestling with the idea of keeping the stock valves in it since the heads are in great shape or picking up some aftermarket SS valves.I finally broke down and ordered some Ferrea valves through a company called ADPerformance, the price wasn't bad about $140 and shipping to Canada is fairly reasonable.There is also a seller on eBay that always has them.The stock multiple groove style valves have a reputation for breaking the tip off in performance applications and I didn't want to see my rebuild money wasted.

 

['69Stang]

I am in the middle of rebuilding a 351c 2 bbl motor myself.I have been wrestling with the idea of keeping the stock valves in it since the heads are in great shape or picking up some aftermarket SS valves.I finally broke down and ordered some Ferrea valves through a company called ADPerformance, the price wasn't bad about $140 and shipping to Canada is fairly reasonable.There is also a seller on eBay that always has them.The stock multiple groove style valves have a reputation for breaking the tip off in performance applications and I didn't want to see my rebuild money wasted.

Good move on the valves. Consider the titanium keepers for better high revving performance, too.

 

[D.Hearne]

Here's a tip for avoiding the multi-groove valves: The 78-up 351M/400 heads had the same size valves as the 351C 2bbl heads but had single grooves instead. They also had iron rocker fulcrums instead of the earlier aluminum ones ( for those who don't want the expense of adjustable rockers)

 

[AustinCobra]

Well guys, six months later and I finally got the motor to the machine shop. It won’t be long now. I’ve reviewed all the messages; thank you all again for your sage advice. And here’s what I finally came up with for a parts list. Again, my goal with this 72 Convertible 351C-2V project is to have a reliable weekend cruiser that can run with the big dogs when it chooses. I want the 351C-2V to put out 350+ HP and 350+ ft/lbs at the flywheel. And since the 72 convertible is a heavy bugger at 3800+ pounds, I want the motor to get to 350hp before 5000RPM. Throttle response is important to. When I step on it…well, as my father use to say,…”When I say JUMP BOY! YOU ASK HOW HIGH!!” Lets just say I’d like my relationship with the gas pedal to be similar.

Summit has put together a kit for me with the following items for about $744. Please review and comment. Your opinions are greatly appreciated.

Summit Engine Kit (as assembled by Chance at Summit, x5813)

Pistons: ($239.60) SpeedPro Aluminum PowerForged 9:1
Rings: ($35.95) Sealed Power Chromemoly Piston Ring Sets
Main Bearings: ($63.95) Clevite Main Bearing Set
Rod Bearings: ($28.00) Clevite Rod Bearings Set
Cam Bearings : ($16.95) Clevite Camshaft Bearing Set
Freeze Plugs: ($8.39) Sealed Power Brass Freeze Plugs
Assembly Lubricant: ($1.50) Sealed Power Engine Assembly Lubricant, 1.5 Oz. Packet
Plastigauge: ($2.39) Plastigauge, Green Kit, 0.001 in.-0.003 in. Clearance Range, Set of 12
Gasket Set: ($52.99) Speed Pro "Musclecar Series" gasket set
Cam & Lifters: ($199.00) CompCams Magnum 280 Hydraulic Cam and High Energy Hydraulic Lifters
Valley Pan Gasket: ($24.39) Speed-Pro Valley Pan Gasket
Oil Pump: ($35.95) Melling High Volume Oil Pumps
Timing Chain: ($69.00) True Roller Timing Chain - Not sure of the brand he’s offering in this kit. Comp, Cloyes, Crane, Edelbrock, etc

Here are some items that are not part of the above kit, but are needed.

Additional Valve train components:
CompCams Magnum Steel Roller Tip Rockers ($149.88)
CompCams Competition Cams Valve Springs ($86.88)
CompCams Magnum Pushrods ($102.69)
CompCams Pushrod Guideplates ($46.39)
CompCams Magnum 7/16 in Rocker Studs ($45.39)
CompCams Steel Valve Spring Retainers ($59.99)
CompCams Valve Locks ($24.88)


Water Pump Options -> Any advice here??

Intake Manifold Options:
Edelbrock: ($194.88) dual-plane, idle to 5,500 rpm
Weiand X-CELerator: ($219.88) single plane, 1,500 rpm to 6,800 rpm

As for the carburetor, I’m thinking a 650-700, but I don’t even know where to start. There are so many. Brand and size recommendations would be appreciated.

Thanks guys!!!

Joe
Austin,TX

 

[ratio411]

Get the Weiand intake.
The 3310 Holley would be perfect... it can be adjusted for best performance and economy mixed. That is the biggest difference between double pumps and vacuum. Double pumps have better performance when tuned properly IMO, but have no potential for economy street use. They also are even more piggish with an auto tranny. Don't get me wrong, I prefer a DP, but I wouldn't recommend one if you don't have much experience with them.
That cam is going to make power further up in the rpm range than what you are saying you want... If you do stick with it, don't even think about a dual plane intake, the intake will be all downhill performance wise when your cam is just waking up.
The 280 will not make good power with an auto tranny and heavy car until almost 3 grand.
The 270 doesn't have as much lope, but will make more useable power for your combo. It doesn't require a stall, but I would use a loose 11" converter for best response.
With a 280 cam, you will want 3.70-4.30 gears with an auto.
With the 270 and auto tranny, you should be able to use 3.50-4.11.
You might squeeze more power from a dual pattern cam, but IMO the rougher idle (rough, not lope) combined with a convertible cruiser is not really worth it.
Good luck
Dave

 

[D.Hearne]

Some food for thought regarding the 280H cam. I used this very cam in a 77 F100's 400M with excellant results. Transmission was a stock C6 from a 72 Lincoln. Converter was also stock. Worked well with these parts. Even used it with a Weiand action plus dual plane intake topped with a 750 Holley. This combo worked well from idle to 5500 rpms, should also work well in a 351C even in a heavy car ( the F100 was no lightweight either) but if you want a bit more bottom end then go with a 270 as ratio411 suggested.

 

[Hack]

Just wanted to mention oiling system mods. But I don't have the details at hand. I hope someone else can fill them in.

 

[AustinCobra]

D.Hearne and ratio411,

On the cam, I guess I'm falling for the old bigger is better fallacy with the 280. So would I get my 350+ Tourque and HP with the 270, just at a lower point? And If I were to go to the 270, should I still stick with the Weiand X-CELerator or go to the dual plain intake.

Any comments on Hack's suggestion of moding the oil system?

Thanks!

 

[dodgestang]

Any comments on Hack's suggestion of moding the oil system?

Thanks!

IMO...unless you are planning on building this thing to spin to 7k or more routinely you don't need to worry about oil mods....if you run solids lifter put in the restrictors and be done with it...if you are running hydro...nothing to do.

 

[D.Hearne]

D.Hearne and ratio411,

On the cam, I guess I'm falling for the old bigger is better fallacy with the 280. So would I get my 350+ Tourque and HP with the 270, just at a lower point? And If I were to go to the 270, should I still stick with the Weiand X-CELerator or go to the dual plain intake.

Any comments on Hack's suggestion of moding the oil system?

Thanks!

Just me, but I'd go with a dual plane. Espescially with a heavy automatic street driven car. Can't recall the specs on the 270H but I run a Crane 272 degree Energizer cam ( .523 lift) in my 68 Mercury Monterey's 390 ( same car as a Galaxie--4200 lbs.) and it works well in there. Reason for going with this cam was price ( $120 from Summit W/lifters) The oil system mods involve restricting the oil passages to force more oil to the rear main. Reason for this is the Cleveland's main oil gallery is the right side lifter gallery also. They have a habit of losing oil pressure thru leakage around the lifters, starving the rear two mains at high rpms ( at idle too) One other way to cure this ill, is to run an external oil line from the front pressure port above the fuel pump up and over the intake to the rear port behind the intake , this port is at the top end of the rear main passage. This line will insure there's plenty of oil to the rear main and is simple to do.

 

[ratio411]

One cube per inch should be no problem with the 270.
I do want to point out that D. was using a 280 in an engine with 50 more cubic inches to tame the cam and he was using a dual plane intake... both combined for a combo that couldn't help but perform at lower rpms.
Dealing with a 351, the cam will not be so tame. Perhaps I was being a little alarmist though, because I was comparing a 280 to one in a 302... again, the same cam will be tamed by 50 more cubes.
So, I have shifted a little... torn between a 270 and 280.
I stand on the mild single plane and 750.
BTW: The 3310 Holley is about the easiest carb to upgrade with Ford kickdown linkage and electric choke.
Dave

 

[AustinCobra]

Awesome advice guys!

One other ingredient I forgot to mention in this stew....I'm planning on putting in a TCI StreetFighter AOD Transmissions with a 3.5 or 3.7 rearend. So if this changes any previous advice, please let me know.

Dodgestang, I noticed you hocked an AOD to your 351 stroker. Awesome! I'll be asking your advice when the time comes.

 

[AustinCobra]

Guys, talk to me about valves. The stock valves look pretty good. But I've head a number of people say ditch'm. Here are the specs on the 280 Comp cam. Can I keep the old valves or do I need Stainless? Also the machine shop mentioned something about new hardend seats for the exhaust side due to the current use of Unleaded fuel. They said the unleaded could burn out the existing cast exhaust seats. Is that B.S.??

Specifications:
* Advertised duration: 280 intake/280 exhaust
* Duration at .050 in. cam lift: 230 intake/230 exhaust
* Gross valve lift: .530 in. intake/.530 in. exhaust
* Lobe separation: 110 degrees
* RPM range: 2,000 to 6,000
* Mild rough idle