Author
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Topic: Stroker pros and cons
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70SportsRoof Gearhead Posts: 313 From: Scottsdale, AZ, but soon to be in Orange, CA Registered: Dec 2001
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posted 05-30-2002 01:12 AM
I posted this in the Classic forum, but figured I'd also post here and get some of the racer's input. I've been thinking of building a stroked 351W for my '70. I was thinking about a 351 stroked to 408 (maybe 427). This car will be a street car, but will be see a few passes down the strip every once in a while. What are the pros and cons of running a stroked motor? Any help you all can give will be appreciated.------------------ Gary- 1970 Mustang Deluxe SportsRoof (daily driver), 1946 Ford pickup, another 1946 Ford pickup, 1947 Ford parts truck, 1957 Ford Fairlane 500 Town Vic [This message has been edited by 70SportsRoof (edited 05-30-2002).]
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jkilroy Gearhead Posts: 1431 From: Vicksburg, MS Registered: Dec 99
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posted 05-30-2002 09:05 AM
Cons? Hmmmmmmm, lets think about this...Gas mileage gets even worse... Rear tires need to be replaced more often... You might have to re-work your tranny to handle all that torque! ------------------ Jay Kilroy 68' Fastback GT 390 "No such thing as a cam thats too big"
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Buster Journeyman Posts: 76 From: Orlando Registered: May 2002
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posted 05-30-2002 09:58 AM
Hummm, More speeding tickets(?) More piston to valve clearance. More HP More Chevy's in the rear view mirror...
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jsracingbbf Gearhead Posts: 121 From: Batesville,MS. , U.S.A. Registered: Mar 2002
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posted 05-30-2002 01:13 PM
the only cons I can think of in running ANy motor that can be stroked or bored to increase displacement is cost. If this is not a problem then I'd do it. Depending on the motor there may be other considerations too. Like it's not always wise to take a 351C out more than .030 overbore. If you investigate all these little details AND money is no problem, then I would go as big as my budget allowed. Talk to people running the same combo you are thinking about. Talk to several of them. There is no shame in copying someone else's set-up. this way you get something already tried. Good Luck and keep us posted on what you decide.
------------------ Jerry Smith 69 Pro ET Mustang 514 cid Alcohol/ Enderle injection 5.60's@ 119 MPH 1/8th http://mustangsandmore.50megs.com/jsracingbbf.html
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n2oMike Gearhead Posts: 876 From: Spencer, WV Registered: Jan 2001
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posted 05-30-2002 02:31 PM
If it's a 351W (which has a VERY strong block) stroke it to your heart's content, and blast it with plenty of nitrous!If it's a 302, which has a rather fragile block, be more careful. A 302 block (with it's stock stroke) is reliable up to around 500hp, as long as it's not run into detonation. This power level is EASILY reached with your power-adder of choice. Stroking it puts extra stress on the bottom end, effectively REDUCING the amount of power the block can safely handle. If you've got much nitrous or boost planned, stick with the stock stroke. If you plan to stay away from power-adders, and not build it too radical, stroking is an effective way to pump up the midrange. 347ci is about the reliable limit for a 302 block, and 331ci is a good compromise. I wouldn't be afraid of a small nitrous kit on a 331, as long as ALL the details were taken care of. The 351 block is a WAY better candidate for stroking. It's MUCH heavier main bolts and webbing stand up to the stress much better than the small 7/16" 302 parts. The 351W also has 1/2" head bolts which do WONDERS in preventing blown gaskets! Any 302 with a power adder is on the edge with 10 measly 7/16" head bolts! Good Luck! ------------------ Mike Burch 66 mustang real street 302 4-speed 289 heads 10.63 @ 129.3 http://www.geocities.com/carbedstangs/cmml_mburch.html http://www.fortunecity.com/silverstone/healey/367 http://www.mustangworks.com/cgi-bin/moi-display.cgi?220
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bluestreek Gearhead Posts: 746 From: Athens,GA Registered: Jul 2001
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posted 05-30-2002 09:55 PM
While we're on the subject... Would it be wise to have the machine shop drill and tap my '69 302 Block for 1/2" bolts since my TFS alum. heads already accept them? Or would it be wiser to have them milled for O-ring? I blew 2 head gaskets last season for no reason. Also, which head bolt set should I use If I have it done?
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n2oMike Gearhead Posts: 876 From: Spencer, WV Registered: Jan 2001
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posted 05-30-2002 10:18 PM
IF you do the conversion, 351W head bolts/studs are what you would use. I did this same conversion to my 68' 302 block, and it ran trouble free for years.To do it... You'll need to install a set of heads with 7/16" bolt holes and use them as a guide to drill out the existing threads with a 27/64" drill. Next, install the heads with 1/2" bolt holes, and use them as a guide to tap the block for the 1/2" threads. You'll need an extra long 6" tap (available from www.traverstool.com ) to do the top holes. A 'bottoming' tap will be needed to tap the holes all the way down. These are also available from Travers. I used ARP 351W bolts that torqued down to 115 ft-lbs bottom, and 125 ft-lbs top. Boring and honing with stress plates is mandatory, as that amount of torque to the thinwall block WILL pull the cylinders out of round. This modification, along with FelPro 1011-1 head gaskets put an END to head gasket problems on my car. I came up with the procedure myself, and many said it would cause the block to crack around the bolt holes, but all went well. A safer alternative (which wasn't available at the time I did this) would be the loc-wire head gaskets. Downsides... The heads need to be machined for the reciever grooves, and the gaskets cost around $50 each. They work great though. Good Luck! ------------------ Mike Burch 66 mustang real street 302 4-speed 289 heads 10.63 @ 129.3 http://www.geocities.com/carbedstangs/cmml_mburch.html http://www.fortunecity.com/silverstone/healey/367 http://www.mustangworks.com/cgi-bin/moi-display.cgi?220
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