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1991 Mercury Cougar LS 5.0 in restoration
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Discussion Starter · #1 ·
As most of you have seen, I have been planning a 5.0 based 347stroker. I recently had a discussion with my oil guy about building vs buying a crate motor and that the crate world has become more performance oriented. I'm thinking block prep/bore/hone, etc. Will run around $800-1000 bucks. A dart block, would cost about 3500 ready to go.

Question: In any world would I want a basically stock 5.0 H.O. sitting, just in the event I thought it would be cool to go back?

The other benefit is I could go 363 cubes for basically the same cost with the aftermarket block. And then if 500+ HP becomes boring, I could supercharge, or turbo that down the road.

I think I'm headed down the road of building my block, but wanted some thoughts.
 

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I would build a slightly hot version of a stock block. Like mine, GT40 top end with a letter cam, just to have on the shelf. Cause an extreme power engine might get to be "too much" for a car thats just supposed to be a cruiser.

But I would look at putting in a 351 based engine with TFS top end and some sort of stroker rotating assembly for wanting to go fast.
 

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1994 Cougar XR7 DOHC/5-Speed
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I’m kind of on the same page block wise, a 351 block is much more stout than the 302 block and has even more potential for cubes, and even 351 is plenty to make strong power with. The best blocks are the 96 ones with factory roller rockers but you can always use aftermarket link bar rollers. If you’re sing a cowl hood anyway thou don’t really have to worry about the added deck height. Though I’m not engrossed in the Windsor world, maybe there’s a larger con I’m overlooking(I know the heads use bigger bolts and the lower intake is different, but all else seems equal)

As for keeping a stock H.O. Motor on the side, that’s up to you. I don’t think there’s much point other than as a large piece of garage art, in car with the build engine I’d just be conservative with the dressup to make it look like it could be stock. Not like onlookers can measure the core and stroke at a show
 

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1991 Mercury Cougar LS 5.0 in restoration
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Discussion Starter · #4 · (Edited)
Ya, unfortunately, I have the K member and driver frame clearanced for 5.0 pan and headers. I have to lower the k to make clearance for the pan.

I can't see a situation where our cars are worth so much stock that it's worth keeping the motor as-is. And really, since I don't plan to ever sell it, maybe I just go with my plan. Like you said, if I wanted it to look stock, 347 cubes can't be seen from outside the motor.
 

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I would go with the dart block. 347s scare me. The wrist pin is literally in the middle of the oil control ring! A 3.4” stroke in a 8.2” deck height block is 10lbs of **** in a 5lb bag in my opinion. Everything is such a tight fit, and everything just barely clears to the point where I can’t see a 347 lasting for 150-200k miles. Like I said, the wrist pin is in the middle of the oil control ring, and the bottomed of the bores have to be ground away so the rod doesn’t hit the block. With the 4.125” bore of the dart block, you can get 347” with only a 3.25” stroke (same as a 331 in a .030” over stock block). That will keep your wrist pin out of the oil control ring, and the wider bore combined with the shorter stroke avoids having to clearance the bottoms of the cylinders to clear the rods. Being able to crank up the power without worrying about splitting the block is just an added bonus at that point. As for having a stock engine to go back in, stock is boring! On the off chance that these cars are suddenly worth a ton of money all stock and you lose your mind and want to sell it, it isn’t like the engine has the vin anywhere on it, so at that point, you could just pick up any 87-95 5.0 block to drop in, no need to store a complete motor for all that time.
 

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Discussion Starter · #6 ·
Ya, I don't really see myself ever wanting a 200hp fury again, but the thought was put in my mind and I guess I thought it was worth discussing.
 

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I really want to see a 10k rpm mod motor.
Oscar is headed that way, and as is usual, life gets in the way.
I'm slowly relearning how to use tools; I have no coordination with my hands. I mow type with one hand, badly.
Relearning how to use a screwdriver really really frustrated me.
I've been working for weeks reassembling a set of c-heads,and lapping is not going well, lol.
 

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Discussion Starter · #8 ·
It would be neat to see, but not very cost effective, or realistic for any street driving. 8k, would be crazy enough.

I guess I am a knuckle dragging pushrod guy. I will say the 5.2 voodoo or the new 5.5 Vette motor sounds are amazing, though.
 

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1994 Cougar XR7 DOHC/5-Speed
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Ya, unfortunately, I have the K member and driver frame clearanced for 5.0 pan and headers. I have to lower the k to make clearance for the pan.

I can't see a situation where our cars are worth so much stock that it's worth keeping the motor as-is. And really, since I don't plan to ever sell it, maybe I just go with my plan. Like you said, if I wanted it to look stock, 347 cubes can't be seen from outside the motor.
If these cars are ever in a position where they do command a lot of money stock I suspect it will be limited to low mile mint survivors, not restorations. Same as Fox Mustangs really, they’re commanding decent coin lately but not a one is a full blown restoration(maybe fresh clear headlights and a long installed CAI kit replaced with a stock airbox or something, but not a blast to bare metal/duplicate factory markings sort of thing), they’re showroom new untouched survivors. Modded doesn’t necessarily hurt value, it’s just a matter of finding the right buyer, something that’s got a lot of personal touches will be a harder sell than something that’s fairly stock appearing but has a lot of desirable and well executed mechanical work.

Even when you think about all those Muscle cars that have been thoroughly restored, how many while appearing stock still have the as delivered bore and stroke? Or stock internals, valve springs and related components, mufflers etc. Apart from a few legit pulled out of a barn with 4 digits on the odometer survivors, most of those cars had liberties taken during restoration, even just RWL radial tires is incorrect for about any car made before 1970 but nobody seems to balk about it
 

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91 Super Coupe
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As most of you have seen, I have been planning a 5.0 based 347stroker. I recently had a discussion with my oil guy about building vs buying a crate motor and that the crate world has become more performance oriented. I'm thinking block prep/bore/hone, etc. Will run around $800-1000 bucks. A dart block, would cost about 3500 ready to go.

Question: In any world would I want a basically stock 5.0 H.O. sitting, just in the event I thought it would be cool to go back?

The other benefit is I could go 363 cubes for basically the same cost with the aftermarket block. And then if 500+ HP becomes boring, I could supercharge, or turbo that down the road.

I think I'm headed down the road of building my block, but wanted some thoughts.
I converted a 93 SC to a Dart block 347 with a turbo. You will need a lot more stuff than the block like crank, rods, pistons, heads, timing set, oil pump and on and on... Here are some pictures from when I had SCU Inc repair and upgrade my damaged 347 (dropped an intake valve). Even after doing every cooling system upgrade possible my biggest issue with the car, was keeping it running as cool as I wanted in the summer. Some people say Dart blocks run hotter, but I think it was more about the FMIC blocking too much air. I ended up selling the car shortly after the fresh motor was installed and retuned.


David
 

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Discussion Starter · #11 ·
I converted a 93 SC to a Dart block 347 with a turbo. You will need a lot more stuff than the block like crank, rods, pistons, heads, timing set, oil pump and on and on... Here are some pictures from when I had SCU Inc repair and upgrade my damaged 347 (dropped an intake valve). Even after doing every cooling system upgrade possible my biggest issue with the car, was keeping it running as cool as I wanted in the summer. Some people say Dart blocks run hotter, but I think it was more about the FMIC blocking too much air. I ended up selling the car shortly after the fresh motor was installed and retuned.


David
Thanks, and I plan on a fully forged and balanced rotating assembly, whether using the stock block or aftermarket. Likely going with AFR 195 or 205 cc heads and comp or Anderson cam with supporting valve train. So really, the question is did the cost of aftermarket block make sense. I'm still not 100% sure what I'll do, but thinking I should be safe at 500 flywheel horse using the stock block.

And I have heard about the rod ratio issues on stock block 347, but newer rings and piston design really helps that.

Ultimately I'll decide when I find a good builder.
 

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1994 Cougar XR7 DOHC/5-Speed
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Why are you spending money on the bottom end like that? Is this video horseshit?
5.0 blocks are very weak compared to 4.6 blocks, they have a tendency to split in half with 500 horsepower and/or high RPM

This is common



As to the video, while I won't call complete bullshit, but there's making 500 horsepower on stock rods and pistons and then there's making 500 horsepower on stock rods and pistons dependably. You need to have the tune absolutely on point with boost at those kinds of power levels, a lean spot here and there and a few passes is enough to melt a hypereutectic piston and bend/break a stock rod. If you have a stock junkyard 4.6 engine maybe it's worth the risk, but if you have a teksid block ported or trick flow heads you probably don't want a rod going through it or a piston and fragments smashing the combustion chamber. It's insurance to beef up the bottom end.
 

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Discussion Starter · #14 ·
Preference. I could make 500hp with a supercharger too, but similar costs and I want N/A for this build. I would really like a TVS 2300 on my Silverado, though🤔
 

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Preference. I could make 500hp with a supercharger too, but similar costs and I want N/A for this build. I would really like a TVS 2300 on my Silverado, though🤔
Yeah, but you could also make over 800hp if you put a SC on top of that 500hp engine.

There is a TVS 2650 that will bolt up to the 5.3L .. just saying. 😉
 

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Thanks, and I plan on a fully forged and balanced rotating assembly, whether using the stock block or aftermarket. Likely going with AFR 195 or 205 cc heads and comp or Anderson cam with supporting valve train. So really, the question is did the cost of aftermarket block make sense. I'm still not 100% sure what I'll do, but thinking I should be safe at 500 flywheel horse using the stock block.

And I have heard about the rod ratio issues on stock block 347, but newer rings and piston design really helps that.

Ultimately I'll decide when I find a good builder.
For the power level you are after, I would look at using a stock 351 block and upgrading to a forged rotating assembly. I don't think it's worth the money and other special parts needed with the Dart block unless you are building for over 1000 HP.

David
 
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