Need your opinion

First off i'd like to say if you think you can swap in a 03 cobra motor for 10,000 you are nuts. You'd be lucky to get the motor and trans for that much, and even if you do, the k-member is going to cost a bundle along with a set of headers and h pipe that cost you around 1500.

I've watched them put a 01 4.6 cobra into a notch at my local shop, it's long tedius and Expensive. They are now modding the brakes to get them to work. It looks to be a project that's going to cost the owner over 15,000 by the time it's done.

Don't get me wrong it's sweet project, it's just sooooo expensive in the long run

I'd also go against the 351, i don't see the purpose in it, when a 347 would be lighter, need less specialty parts, and produce about the same HP.

There's a guy down at the shop that has a gt with a 347, N/A with a sportsman block, made 444 to the wheels and ran mid 10's. Motor looks the same as any other modded 5.0.

For cost and only cost I say the 351. I vote 351 for the strength of the block vs the 302 block. Now if you want to go with a sportsman block or a dart block, then whatever. I think a 351 turbo with some 3.08's or 2.73s and a c4 would be sweet combo and a ton of fun to drive.

Are you going to try to make a water injection system out of your washer reservoir again?

Sounds sweet. If you need to buy the manifold, may want to consider a trick flow, but if not, you can make plenty of power with that turbo pushing some boost through almost any manifold. Good luck!

With a large motor and a turbo it's not going to be so mild mannered. The bigger the motor the faster the turbo spools. BD has a 347 with i think a 90mm turbo and the car makes 1300+ (dyno only went to 1300) and he ran it all season. So i'm sure something more mild could last much longer.

I believe the Sportman, Dart, A4 (if it's not the same as the sportman, can't remember) blocks can handle major hp if built correctly.

Just something to think about.

Wish I had your problems

2000xp8 said:

With a large motor and a turbo it's not going to be so mild mannered..

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Not necessarily. Keep out the boost and it should run/idle etc like stock. This is where the tune and good selection of the right parts will come in to focus.

My setup is pretty well mannered, it might smoke you too haha 500HP

hllon4whls said:

Not necessarily. Keep out the boost and it should run/idle etc like stock. This is where the tune and good selection of the right parts will come in to focus.

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Problem is that the larger motors spool so quickly it's hard to stay out of the boost.

"Problem is that the larger motors spool so quickly it's hard to stay out of the boost."

It's all about selecting the proper size turbo to achieve what you're trying to achieve. Mercedes new 5.5L V12 twin turbo powering the Maybach makes almost 600 lb-ft of torque at 1800 rpm (talk about quick spool) and 500HP at 5000 rpm. It's VERY mild mannered.

Michael Yount said:

"Problem is that the larger motors spool so quickly it's hard to stay out of the boost."

It's all about selecting the proper size turbo to achieve what you're trying to achieve. Mercedes new 5.5L V12 twin turbo powering the Maybach makes almost 600 lb-ft of torque at 1800 rpm (talk about quick spool) and 500HP at 5000 rpm. It's VERY mild mannered.

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Exactly!!! I was choking through the posts. Where does anyone get the idea that running a 351 over a stroked 302 will cause driviability issues? Sure, you can build a 351 that will make all kinds of drivability problems but the same can be done with a stroker. I guess my point is that it's the BUILD of the motor and combo that will determine drivability. Not whether it's a 351 or 302 block. Under that logic, Ford should be putting out a recall for all 351s ever produced. They're a menace to society.

hllon4whls said:

Are you going to try to make a water injection system out of your washer reservoir again?

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Michael Yount said:

"Problem is that the larger motors spool so quickly it's hard to stay out of the boost."

It's all about selecting the proper size turbo to achieve what you're trying to achieve. Mercedes new 5.5L V12 twin turbo powering the Maybach makes almost 600 lb-ft of torque at 1800 rpm (talk about quick spool) and 500HP at 5000 rpm. It's VERY mild mannered.

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I think comparing the technology between a 10,000 dollar motor built in your garage and a 300,000 dollar benz is really not a fair comparison, especially since one of the cars weighs like 6000 pounds, and the other 3200.

Daggar you probably have a point about the 351 vs stroker 302. But still any street car with a big turbo is going to have some driveability issues.

2000xp8 said:

Daggar you probably have a point about the 351 vs stroker 302. But still any street car with a big turbo is going to have some driveability issues.

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Perhaps... but if I were to put that SAME big turbo that was causing a 351 drivability problems onto a 302 based stroker then I'd still have drivability issues. This would be an extreme example but let's assume for a moment that we took a DSS Level 20 347 build and topped it off with a ported GT-40 lower and a 2.2L KB blower (very streetable). Without taking into account the cam and compression, I think we could all agree that the basic description would conjur thoughts of all sorts of wheel spinning bottom end grunt regardless of street and weather conditions. The mere mention of a built 347 suggests that sort of result. Drivable? Sure it is. Ideal for a gas concious daily driver? Hardly. Put that same lower and blower on a 351 and I can still envision pretty much the same result. The only difference I would expect initially would be that the 347 would be considerably more agressive due only because I would have expected that 347 to be BUILT more aggressively (why else go through the trouble and expense of building a stroker?). Now... once we start talking specifically about cam and compression and all of the other things involved in making an agressive motor agressive well... Sure, either one could be made into a monster that would be a nightmare for street driving. A broad statement stating that a blown 351 would be unstreetable compared to a 302 based stroker without taking build variables into account is incorrect. Inferring that a 351 would spin up faster than a 302 based stroker without taking build variables into account is incorrect. Saying that it would be harder to stay out of boost on a 351 vs. a 302 based stroker without taking into account build variables and method forced induction would also be incorrect. Even fuel mileage between the two builds could not be considered without knowing setup and tune. I've seen some very nice (and even gotten to play with and drive one or two) blown 351 applications. Let's not forget all those blown 351 Saleen packages that were so sought after a while back.

Seems a perfectly valid comparison to me. You made the generic statement that the bigger the engine, the quicker the turbo spools. And it simply is an inaccurate statement. Speed of turbo spool has much less to do with engine size, and more to do with turbo size. A very small engine can be made to spool it's turbo very quickly (very small turbo) and a very large engine can have relatively slow spool speeds if you put a very large turbo on it.

The variable isn't so much engine size or load (the reason I used the Benz analogy) as it is proper turbo sizing. Cost of the engine has nothing to do with it - unless of course you're just bolting on a junkyard turbo of any size because you can't afford to actually design or have the system designed properly. In which case you may well draw the conclusion that bigger engines always spool more quickly.