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Smoked another 347

M

Mustang Mike

Member
Well, I burned up my 347 last week. Melted all 8 pistons. I had a good tune with my suprcharger and haven't had any problems until I added Klotz octane additive. Also broke the block straight down all the webs from the cam bearings to the main cap bolts. Good news is, I'm building a 351W for temp use until I can build a monster 408. I'm selling the Weiand 174 and going naturally aspirated.
 
Seems like "octane additives" are always bad news for boosted vehicles. How much boost was you running?
 
That sucks. I'm not an expect but I've seen a few pics in magazines of 302's splitting at the lifter galley becaue the OE block could not handle the high horsepower of that particular combo which was usually due to a power adder such as a blower, turbo or a huge shot of nitrus.
 
"SAC69" said:
That sucks. I'm not an expect but I've seen a few pics in magazines of 302's splitting at the lifter galley becaue the OE block could not handle the high horsepower of that particular combo which was usually due to a power adder such as a blower, turbo or a huge shot of nitrus.
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+1

That's why the 351w swap is so popular for high HP uses.
 
"Shaun" said:
Or a Dart or BOSS block.
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Very nice, but at nearly $2k a stock 351w can handle about as much HP and can be had for a few hundred $. For well less than a grand you can get one fully prepped and set-up for a stroker crank. If you really want to go aftermarket blocks I think you need to include the WOP Man-o-War blocks into the discussion as well.
 
"Horseplay" said:
Very nice, but at nearly $2k a stock 351w can handle about as much HP and can be had for a few hundred $. For well less than a grand you can get one fully prepped and set-up for a stroker crank. If you really want to go aftermarket blocks I think you need to include the WOP Man-o-War blocks into the discussion as well.
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But if weight and header clearance are important then that may take over just what is cheapest. Not to mention header choices and prices.

Is the stock 351w really that much stronger in the casting?
 
"Shaun" said:
But if weight and header clearance are important then that may take over just what is cheapest. Not to mention header choices and prices.

Is the stock 351w really that much stronger in the casting?
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Supposed to be significantly stronger according virtually all the sources I have ever read or talked to.
 
"Horseplay" said:
Supposed to be significantly stronger according virtually all the sources I have ever read or talked to.
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Ahh, didn't know that. Still not sure if I'd want to deal with squeezing one in a 65-66 and having to change headers etc. Shooting for 450-500Hp out of the next motor which should be safe on a regular 302 roller block don't you think?
 
Plenty of people have that amount at the crank and seem to do OK with it. Then again, they don't really USE the power like you would. I would say if the block is prepped well by someone who knows this engine (de-burring and grinding to reduce the chance of stress cracks, etc.) you would be OK. I would suggest you talk to a few trusted engine builders and get their opinion too. If you went with the new Ford block you'd be safe for sure.

FWIW, supposedly a good 351w block is good for up to 700 H.P. It really is a much stronger designed block.

With your new front suspension you could also easily mod the towers and gain plenty of extra room for header clearance, etc. IMHO, the only draw back to dropping in a 351w is the tight confines. Not a lot of room to let the engine breathe with big header tubes.
 
I think you'll be fine with a 347. My buddy Dean built his 347 drag motor to spin at 8,000rpm and IIRC, it is putting almost 600HP to the ground. He's been running now for about 6 years with no major failures...unlike me!

He's been trying for years to convince me to build a 347.
 
OK guys, here are some pics. I've decided to sell my heads and supercharger. I'm going with bigger heads on the next build. These are TFS with solid roller springs rated up to 700 lift. These valves were replaced recently to get a higher spring height for my cam requirements. I dis assembled the heads several days ago and re-lapped the valves and they look great. The ports have been cleaned up and port matched to the blower manifold. You can see all the pics here:
http://www.cardomain.com/ride/2981459/1968-ford-mustang/page-40
The blower works great and comes complete. All for $2250 + shipping.
DSCN2346.jpg

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