302 VS 347 Really a horsepower difference?????? - Hot Rod Forum : Hotrodders Bulletin Board
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Old 07-07-2003, 03:00 PM
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302 VS 347 Really a horsepower difference??????

I have read so many things on stroking a 302 to a 347 and making loads of horsepower, but it seems to me that everywhere I read, the horsepower isn't really much more than just the plain old 302. Can anybody help me out? How much more horsepower are guys getting from a 347 as opposed to a 302? And if it is really a good bit more than what makes so much more power? I already know that the stroke is longer, but after buying a stroker kit and having everything machined, does it justify building a 347 rather than a 302??

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Old 07-07-2003, 04:01 PM
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building a bigger motor wont help horsepower only move the powerband down in th erpm range and deliver more tourque at low rpm, that is UNLESS you add heads that can deliver the needed airflow. so if you build a 347 and add a pair of Large runner heads like AFR 220 or this, which i considder to be the deal of the century: Yates heads

they will deliver aiflow upto 700 Hp at 9000 rpm and they sell at 1950. which is about 5000 below the new price
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Old 07-08-2003, 06:13 AM
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anybody has thoghts on this?
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Old 07-08-2003, 03:29 PM
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Quote:
Originally posted by lakecityg
anybody has thoghts on this?
Im not a big fan of the 347 stroker, for the price you could build a 351W and stoke it up to 454CId <<<(aftermarket block) But with the affordable good flowing heads, I like the 393 stroker, because keeping the cubic inch below 400 CID alows decent rod ratio and doesnt eat up piston skirts...Its hard to beat factory rod ratios so a 306 built right will run...and last...I know for a fact the 302 is a very, very tough motor and I suppose ford tough...Im building chevys now, but the top end of a high strung ford still gets my heart a poundn....
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Old 07-08-2003, 06:05 PM
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Arrow

More inches always is good, but as has been stated a 351W is a better way to go. The difference is that a 347/302 is at the top of it's capacity and the 351W is there without any stretch.
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Old 07-08-2003, 06:20 PM
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347 is better in many ways, as well as the 351. 347 can be cheaper for parts, and shedds 100 pounds off ur car opposing the 351. with the 351, u can have more potential hp wise and u can buy a 408 stroker but, the 351 is 100 pounds heavier, but with enough knowledge and good parts the power to weight can easily be fixed.
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Old 07-11-2003, 09:32 AM
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the yates heads are winston cup spec. and deliveres 700 Hp with a single plane and restrictor plate on a 358 cui, what more do you want, if you build a 347 you will be almost 100 lbs lighter and up into the 550 Hp mark on pump gas and a relatively streetable cam
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Old 07-11-2003, 11:22 AM
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It is personnel preferance with the 302 or 347. There is no replacement for displacement, but you can build a 302 to have as much horsepower as a 347. The 347 I think is better for drag racing than the 302 but not because of horsepower but low end torque.
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Old 07-12-2003, 09:33 PM
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how tough is it to get a 347 running mid to low 11's?
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Old 07-13-2003, 02:21 PM
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how much does the car weigh?, What tires do you run??, What tranny???, What gearing, how much notrous??? Please giev a little more info before asking...
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Old 07-13-2003, 07:41 PM
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My Bud has two identical Mark VIIs. One has the stock 302 and the other has a built 347. The Ford fuel injection was replaced with the Holley EFI that utilizes the stock wiring and chipped computer. He beefed up the OD tranny to the limit and has a real killer of a Granny Grocery Hauler. Don't think a 302 is going to touch it with out being very radical and in a lighter vehicle.

Trees
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Old 07-13-2003, 08:06 PM
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Quote:
Originally posted by deuce_454
the yates heads are winston cup spec. and deliveres 700 Hp with a single plane and restrictor plate on a 358 cui,
we don' need no stinkin' restrictor plate.......


what's this going in? if it'll fit, go ahead and get a stroked 460...... save yourself the aggravation and go ahead and do it..... you'll be happier in the long run.......
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Old 07-13-2003, 09:20 PM
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347 burn more oil than normal due to the piston's skirt falling out the bottom of the cylinder. Oil cotroll is a real problem. 347's don't live as long either because of the increased rocking of the piston due to the very long stroke. I don't recomend them to any one for street use. I rather see them as race only.
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