Attention: Brent Lykins
 

Brent: I would really appreciate your thoughts and feedback on the following combination I'm in the midst of assembling, as I write this, for my Cobra. I saw your post below and thought you really seem to have a good feel for these small block Fords and might have an intersting perspective on my build. I'm trying to build a very "streetable" motor here yet something that will still push me back in the seat a bit. I've intentionally stayed away from the radical stuff because I don't want some hi rpm wonder that won't run under 2,000 RPM. Tell me what you think here with this combination of parts--good, bad or ugly. Thank you.

408” 351W based stroker motor
Engine short block: Late model 351W factory roller cam block. Casting number: F4TE 6015 AA 14 Bored .030”

Crank: Eagle Forged 4340 Steel 4.0” Stroke.

Rods: Eagle Forged 5140 Steel ”I- Beam” 6.200”

Pistons: Probe Industries Forged Aluminum SRS 4.030” bore Reverse Dome 22cc p/n 12360-030 (Compression ratio should be about 10.09:1 with these pistons and the Edelbrock heads with 60cc chamber volumes?)

Cylinder Heads: Edelbrock Performer RPM #60259 Alum 2.02” Intake Valves, 60cc chambers

Intake manifold: Edelbrock RPM Air Gap 351W #7581

Carb: Holley Model 4160, 750 CFM, manual choke #0-3310C

Camshaft: Hydraulic Roller 510/534 Lift, 222/232 duration at .050, 114 LC
Camshaft Hydraulic Roller Lifters: Ford M-6500 R302
Roller Rocker Arms: Competition Cams #1131-8
Hydraulic Roller Lifter Retainer and Spiders : Factory Ford

Crankshaft Damper: Ford Racing Nodular Iron, external balance #M-6311-K351

Oil Pan: Milodon 8 quart louvered
Oil Pan Windage Tray: Milodon 2215
Oil Pump: Melling High Volume #M83HV

Timing Chain Set: Edelbrock #7811 Performer-Link True Roller chain set

Distributor: MSD Pro Billet Small Diameter, Magnetic Trigger #8478
Distributor shaft Steel Gear (#85834) and installation by MSD factory

Spark Plug Wires: Ford Racing black 9MM

Spark Plugs: Champion RC12YC (Recommended by Edelbrock for use with their alum heads)

CV Products Air Cleaner base and lid, offset, 14” diameter 3” thick element

Tremec TKO 600 .82 OD 5 speed transmission
Ram Alum Flywheel 28 oz 157 tooth #2527
Ram Clutch and Pressure Plate
QuickTime Bell Housing#6065

Complete engine balancing: Crank, rods, pistons, rings, damper, flywheel, pressure plate via Freeway Auto

Hey Tim,

The key to any well-thought-out engine build is matching all the components together to fit the rpm range that you'll be driving in.

Let me preface my thoughts by saying this: almost any amount of horsepower in a 2400 lb car is going to make it boogie. So you have reached your goal of wanting to be pushed back in your seat.

Looking at your combo, I think you'll be pretty happy with what you're working with. However, if it's not too late, I think I'd bump up the camshaft. You're leaving a lot of power on the table there. That is a cam that I would put in a 351-sized engine. A larger engine (50 cubes larger in your case) needs a lot larger camshaft because it needs to fill a lot more cylinder volume. Your cam in a 351 would put hp peak (depending on the cylinder head, but using your heads as an example) at about 5400-5500 rpm. That same cam in a 408 will probably drop the peak by about 500 rpm.

This engine would definitely be a torque monster with your current cam and it would be very gentle and streetable. If that's your goal, then you're there. My guess is that you'll be somewhere in the 415/425 hp range with all of the parts that you listed above.

If you decide to play with the cam selection a little bit, I would recommend Comp's XFI line of cams. The XFI236HR-14 (part # 35-775-8) cam would really wake that engine up and it would still be as docile as you want it to be.

With the larger camshaft, you'll gain about 30hp at peak, and probably 15-20 average hp(power across the entire curve). The hp peak would occur at 5500, still not revving the engine hard and still keeping a broad powerband.

You may also want to trade the timing chain for a chain with a lot of different keyways. If you can degree a camshaft, it will allow you to put the cam timing exactly where you want, instead of being hampered by just putting it straight up, 4°R, or 4°A. Sometimes the cams are off by 2° and the good sets will allow you to account for that. I like the Ford Racing M-6268-A302 set for builds like this. They will allow you to really fine tune the cam timing.

Other than that, take your time and double check everything: bearing clearances, degree the cam, intake manifold fitment, etc. It should make a super nice engine. If you bought your heads assembled, double check the spring pressures. I've never used a set of the RPM heads, so I don't know what they come with, but make sure they're adequate for a hydraulic roller. Chances are that they will be fine for your current combination.

Many thanks Brent. Good thoughts and advice. I'll rethink the camshaft.

-Tim

OK. I have nothing to say on the overall setup of the engine, and I think Brent's thoughts are correct. But I'd like to ask one question.

As you are going with I-beam rods and quite low- reving engine, will a forged crankshaft be what you need? Will a cast crank do the job?

RS

RS: I purchased a 408" short block assembly from Dyna-Flo out of Nevada. It was suppose to come with a cast crank but I told them I needed a 28 oz externally balance set up and apparently they didn't have any more cast cranks in stock and substituted the forged crank. I know this conclusively because I was able to trace the Eagle part number on the crank flange to Eagle's web site.

Probably much more "stout" then I need but I figure it didn't cost me any more money for the forged crank and it leaves me much room to add more horsepower down the road if I so desire.

-Tim

Be careful,Tim. I started out planning for a warmed up 302 and ended up with a beast.
Bill Stradtner

That's awesome that you were able to get a free upgrade. Definitely overkill, but will give you some peace of mind if you ever wanted to go wild.

Tim,

I'm selling a slightly used cam that would fit your combo well. I had this in my 427w for a while. Would cruise at low rpm's all day. Nice flat tq curve too. Great cam for the street.

Let me know if you're interested.


http://www.clubcobra.com/classifieds...p?product=2734

Thanks,

Thanks guys but I'm going to go with the cam in my above specs. I bought it from Mike Forte and he swears 500 hp with an almost identical build configuration to mine based upon the Edelbrock RPM heads and similar compression ratio. I know that sounds like a lot of HP for the cam configuration but I'm still okay with it, even if it is significantly less HP when all is said and done as I want something that is very tractable on the street first and foremost. Besides, 400+ hp will move my lightweight Cobra down the road just fine....

Good thing it was a free upgrade, then, Tim.

But you know what they say; a forged 351 crank can take 15- 2200 Hp. So, then; you'll have to upgrade all other parts!

500 Hp from a 408 would definately give me confidence.. No need to high rpm's or power adders. will take & make the beat as is....

Run

Nice running package - but Brent is correct - nowhere near 500. I'd also go up on the cam. That one will idle like a kitten in a 408....