302 vs 351?

[RallySnake]

THANK YOU!

It's good to hear some reason on this forum.

Paul

[hssss]

One of the major decision points hasn't been mentioned. I am frugal/cheep so the thought of a 4k+ aftermarket block gives me some concern. That said if using a production block based Windsor you need to keep in mind the breakability of the final product. It is well documented that the 302/5.0 has a couple of major strength problems. Thin deck, when you hear of someone who is making some power blowing the head gasket generaly it is because the deck is so thin that it moved around. A patch is to O ring the block but it is just that a patch. The more serious involves the block splitting in two down the middle sometimes even at "stock" power levels. at 350+ it generaly isn't if but when. The 351 Windsor, they are both the same basic design, has thicker decks and more metal in the bearing webs and generaly dont have those problems. To me what I'm doing for a 1600 lb Lotis 7 which by design is basicly a Cobra light weight works and is reasonable. I'm using a 96 F250 roller block (125 for long block) which will have a forged 3.85 crank (500?) stock 351 truck rods forged 302 pistons (400?) aluminum heads which will probably be somewhat cost driven Crane cam using factory roller lifter pieces and Crane Cobra rockers with an EFI. I expect nominaly 450 Hp but should be better and should be very reliable. I expect the car to give new meaning to the term traction limited even with 315s and generaly not be able to use more than a quarter throttle. I don't expect to have as much in the whole car as what has been mentioned in this thread. Bottom line unless required by a racing class restriction I would never use a 5.0 though my primary DD for the last few years is a 93 Cobra when it dies it gets a 351.

[Fred Z]

Capt. H........well, dude, you asked, and not going to be easy to decide....as these guys know their stuff, and obviously have varied opinions!! Here is mine....as i just sold my 1st Cobra......and building a new one, very custom! The 1st......had a 351 moved out to 418...505 hp with 528lbs of torque! No doubt, had more hp than needed and could feel it had too much many times.........BUT that sound, that power , and that knowledge........that if needed, could blow everyone away......and probably me too!! Now, I am going for a CHP motor........351 stroked to an actual 427....will have 550+hp and big torque too! I added 'mass -flow' EFI which gives the look of the carb, but the control, fuel milage, and streetability of a powerful engine and easier to start, and such.........just better IMHO. But , and here is the bottom line........these cars are a special deal.........they are good looking, timeless to be sure, and they command attention.......you can drive any motor you like........only you can determine what is right, or wrong! Now, if certain other factors engage......ie: sale ability later.....or safety on a daily drive....or just plain money savings......then that is a different matter, as all these gentlmen have covered! One thing does, however, seem to be continuous..........that the Cobra you own, is one fun car, to be taken very, very very seriously, and if you have the "need for speed".....then go with power, and be sure to update your insurance policy as well as your will!!!
Have a good experience.........it will be like no other one in a "seat" that you will ever duplicate!
fred.

[hssss]

Like Fred Z said it's your car determine your goal and go for it. A few things to remember while building. "Too much is just about enough" "You can't win if you dont finish" (many races are won by a slower car) and fineally "It's realy pissing offing to have to get out and push"

Have fun

[Rick Parker]

You don't NEED more power. But, after bitten, you WANT more power.

Very well said Rally Snake!

My car is a little unusual comparatively speaking, it is a 289 bodied NAF. Not an FIA wide hipped type but a slabside with the wheel arches tastefully widened about 2", so it accepts a 289 very well and THAT is the correct motor for it. When I built the engine it was originally built to 289/ 271 K motor specs. Later I changed the heads, cam, intake and headers. I have never desired a larger engine, but more Horsepower like all of us. Currently it's developing about 380HP as it is now and it hooks hard and rpms very quickly. Understandably it is not a torque monster so it does not overpower the tires past 2nd gear, the car just squirts like a "watermelon seed". It is very quick through the gears. Do not sell a well built "Real" small block short.