Low Budget 300rwhp engine. Please Help!

[mattr762]

As some of you know I'll be getting a Cobra soon. Here are some of the engines I'm considering based on my wants and needs:
- 4.6L modular SOHC (used for $2000) 230rwhp stock/270rwhp with simple mods
- 4.6L modular DOHC (used for $4500) 270rwhp stock/300rwhp with simple mods
- 302 Price ??? anywhere from $1500 to $6000??? HP wide range
- 351 Price ??? anywhere form $1500 to $8000??? HP wide range

Needs:
- Costs $2000
- Cobra as a daily driver (weather permitting) 40 mile commute
- 20mpg +
- Easy, reliable starting (even for the wife) including cold starts
- Easy, smooth driving (wife's gotta be able to handle it)
- About 300rwhp
- Occasional racing
- 12-12.5 1/4 mile
- Light for auto cross/track

Here is the main question:
Can I build a 351w that fits my needs?
Do I have to go to the salvage yard and find one for $500 and rebuild it myself? Do I really need forged crap and blue printing? That seems to add a ton of dough.

Please give me ideas.

Thanks,
Matt

[Edley Rondinone]

IMHO, the 302 will be cheapest; slightly more with the 351W. In proper tune, most engines start right up. Keeping the revs up until operating temp takes about a minute.

I assume your wife can drive a stick shift?

The tamer the moter is, the better MPG you will get. I have about 400 HP, and I get about 16 MPG on the freeway, with my 3.05 gears. A stone-stock 302/5.0 could get 20 MPG.

I still havent taken my Cobra to the drags, so I am not sure about the times; probably in the 12's. (I REALLY got to get to the drags!)

What do you mean by "smooth driving?"

First line under "NEEDS" is 'Costs $2000.' Please explain.

Well, its a start, anyway!!

[blykins]

Did you check out Ford Racing's 345hp 302?

[blykins]

Oh another thing you want to consider....the modular V8's are very very wide....especially in DOHC form. Your choices of Cobras that will handle that will be slimmer than a regular pushrod V8. Also, later on when you get the itch to upgrade the engine to over 300rwhp, it will be a lot easier with a pushrod V8. A set of hipo cams for a modular 4.6L will run you anywhere from $500-$1000. You can swap roller cams for about $225 in a regular V8.

Also, I would rather have a carb engine. But that's just my taste. I would rather just tune it myself than have to worry about wiring harnesses......computers....sensors....etc.

You say potato, I say po-tah-to.

[blykins]

$3100 for Ford's 345hp 302. I think that's pretty cheap horsepower. Plus it's something you can work on. I see that it has GT40X heads and a pretty mild cam. With a couple of goodies, the horsepower would go up quite a bit.

[392cobra]

Matt,
To get to 300 rwhp you will need (roughly) 385 hp with a live axle and 425 hp with a IRS.

Ford sells a crate 351w at 385 hp.

[aumoore]

Here is what I did
Used very low milage 1997 Mountaineer 5.0 $1000
sold EFI crap for about $200 net
bought Holley 600 vac secondary $225(higher now)
Edelbrock Performer rpm intake $145
Mallory Unilight distributor $225(will run without box)
Trick flow stage one cam $140
Motorsport fox conversion kit $200
MSD coil $35
Moroso plug wires $40
motorsport valve covers and air cleaner $120
rebuilt 1985 mercury water pump $17
March alternator bracket $62
motorsport flywheel $100
rebuilt 1970 ford alternator $20

all the above netted in 267RWHP and 285 rwtq on a dyno. I have a 1985 corvette IRS so I can brobably day at least 17-20% drivetrain loss whick puts the flywheel numbers at around 321HP and 343TQ. I come up with a total of $2129 after I sold the EFI stuff. Now this motor had 12 miles on it from a FoMoCo test vehicle whick I doubt any still exist but there are a lot of V8 Exploders and Mountaineers with the 5.0 with the GT-40 or GT-40p heads. You should be able to find a good used Exploder/Mountie motor for under $1k and it should have had a pretty easy life compared to a GT stang.

300rwhp will probably require aluminum heads and a more radical cam. I do not think you realize how fast a Cobra can be with a stock 225 flywheel HP 5.0 motor. In a FFR that weighs about 2200# that is under 10# per HP. My car weighed 2450# on the same scale Engineer Ed's FFR weighed around 2200#. They will both get around a track pretty good. He does have a stroker(347) with ported GT-40 heads and he was over 300 rwhp.

I have since added a Mallory Hyfire digital box, Canton road race pan with windage tray and FMS roller rockers. I can tell the engine has more power so I may be pushing your goal.

Look for a GT-40p head motor and you will be pleasantly suprised.

[jarendall]

The Engine Factory ( which Advertises on this site) builds a real strong engine, for the price. I have a 302 with 350HP, the car will scare you to death, when you get on it. I am not easy to scare, have owned a 383 Road Runner, 350 Nova, 340 Road Runner, 454 Chevy and several other so called fast cars, this Cobra is by far the fastest I have ever owned.

I think you can find their site at www.cobraengines.com

[Back in Black]

Mine now has 576 horsepower.. quite a few cobras on this site have MORE hp..now my original motor was not putting out that much (due to several major engine problems as delivered to me by WCC) however it did not scare me in the slightest.. but I did respect it,... any high powered car with this short wheelbase and the "break-away edge" of traction loss MUST be respected or it's adios!

[mattr762]

What is everyone's thoughts building a motor like this? Car Craft's 302 400hp engine

If I started with a used '91 Mustang For $500-$800 and rebuild it, I'd be set, right?

How much does the average machine shop charge to rebuild?
How much do they charge to just clean it up and I rebuild it?

[RockSnake]

The AFR heads sound almost too good to be true. I really like the little 302. They rev VERY fast, but are not known for low-end torque. GENERALLY SPEAKING, high horsepower engines are sluggish from a stop-sign when driving sedately.

As previously stated, these cars are so light-weight that large horsepower is not necessary for quickness. To put this in perspective, my 302 can break the tires loose WITH THROTTLE ONLY in the first four gears. Of course, that isn't normal driving, and it took a lot of throttle. But for the purpose of demonstration, it was effective.

Also, mods will cost you mpg. Mine was built as a daily-driver, and is all roller, with an E303 cam. Fuel efficiency runs about 17-18 mpg.

One last comment. After 18 months on the road, my wife is still too scared to drive it.

[grumpy]

Back in Black,
Trying to figger if I have ever drove a small block that scared me?
NOPE, cain't think of a one!
grumpy

[tfarhood]

Daily driver..
Ask your insurance company about a Cobra for a daily driver. Your rates, if they insure you at all, are crazy. Now, as a non daily driver titled as a 1965 is about $350/yr with the usual restrictions, and a 2004 titled car is about $650/yr.

20 miles per gallon.... better get a 5.0 with fuel injection.

a 4.6 will limit you pretty much to a Factory Five kit.

Unless your wife is already a street racer, don't give her the keys to a car that can do a 12 sec. 1/4 mile. Or yourself for that matter.

If you really want 300 RWHP, yes you do need forged crap and blueprinting.

See if you can drive someone elses Cobra to see if you really need all that HP to be happy. A lot less HP can still get you into a lot of trouble in a Cobra. 300 RWHP can be very scarry if you don't use it properly. Ask any of the 600 HP guys out there if they ever get to actually use all that power regularly, or at all. A trained racecar driver on a track can barely use 600 HP in a Cobra. Don't under estimate the power of these light weight cars.

Good luck in your search, and don't let any of us intimidate you at all. The real message here is to do your due dilligence, and find out what you really want, prioritize it, and then make an informed choice. Your original post seems a little out of reach if you want everything listed. You are fighting the laws of physics and the laws of economics.

[jhein]

Well, I have a mere 350 rwhp (non-stroked 351w) and it's pretty da?n fast. I know that lot's of people here have more but what they do with it, other than spin their tires, I don't know. Also, from what I have learned, it's hard to say what all these chassis (or other) dyno numbers really mean.

I do know that for less than 8k (for the motor) you can get your 300 rwhp in a 351, easy. Of course this is not a home built, junk yard salvage motor. Forged crap and blue printing sounds like a good thing to me.

John
spf1421
351w 480hp/437ftlb at the flywheel

[392cobra]

"What is everyone's thoughts building a motor like this? Car Craft's 302 400hp engine

If I started with a used '91 Mustang For $500-$800 and rebuild it, I'd be set, right?

How much does the average machine shop charge to rebuild?
How much do they charge to just clean it up and I rebuild it?" -Matt


Those AFR heads cost $1,300 alone. They had $ 2,200 in that engine without the cost of the engine.

So,adding $ 800 for a stock bone yard engine = $ 3,000.

Start adding in a rebuild on top of that.

You would be way ahead buying a crate motor in the long run.

Even if it has some forged Cr@p in it.