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Old 04-26-2014, 12:51 PM
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Wrong piston rod lenth? ? ?

Dose this block has the wrong connect rod???
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Old 04-26-2014, 01:23 PM
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Originally Posted by stevetankl View Post
Dose this block has the wrong connect rod???
Are the piston supposed to be flushed with the deck??? Will 6.0 rods this??? The motor is an sbc 400 stock crank stock rods.
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Old 04-26-2014, 02:25 PM
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They normally sit roughly .025 below the deck unless the decks have been cut. At top dead center how far is that piston down the bore? In the picture it looks like about 1/8 inch.
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Old 04-26-2014, 02:33 PM
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If that is the roughly 1/8" down at top dead center that the pictures look to be, then yes, the wrong rods were used.

If that is with 400 crank and stock 5.565" long 400 connecting rods, then you need to have 5.700" connecting rods(Typical stock 327 large journal/350).

The 5.700" long rod/400 crank combo is probably the most common, along with 6.00" rod/400 crank.

6.00" rods with those pistons however would put them up out of the block more than 1/4"
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Old 04-26-2014, 04:37 PM
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Interesting. Sa I look at the pics. The top ring wear pattern looks higher on the third (far right hole) and lower on the other two.. Are they all the same pistons? or did someone mix rod lengths on the engine. I saw a local "engine builder" do that to a 400 once. six 5.7 rods and two 400 rods he aparently didn't know the difference..
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Old 04-26-2014, 05:12 PM
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Quote:
Originally Posted by engineczar View Post
They normally sit roughly .025 below the deck unless the decks have been cut. At top dead center how far is that piston down the bore? In the picture it looks like about 1/8 inch.
Yea they all sit about 1/8 inch below! So how can I correct this? Should I correct it? Will it make a difference in the hp?
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Old 04-26-2014, 05:54 PM
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As is it will kill performance, and your c.r., same as having dished pistons, except your quench distance will be HUGE. You need either different compression height pistons or different rods, depending on what you have now, do some measuring. IMO go the new rod route as pistons and p/w clearances could be different in each bore.
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Old 04-26-2014, 06:08 PM
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Quote:
Originally Posted by stevetankl View Post
Yea they all sit about 1/8 inch below! So how can I correct this? Should I correct it? Will it make a difference in the hp?
7.6-1 compression with a 76cc head, 8.3-1 compression with a 64cc head, but has been mentioned - terrible quench and poor burn characteristics.

Easy fix, put 5.7" rods in it. Or pistons meant for the short 5.565" rods, take your pick. The 5.7" rod way is the better way.

It'll be a slug the way it is now, you gotta correct it.

70-100 hp difference,.... if not even more
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Old 04-26-2014, 06:45 PM
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Quote:
Originally Posted by ericnova72 View Post
7.6-1 compression with a 76cc head, 8.3-1 compression with a 64cc head, but has been mentioned - terrible quench and poor burn characteristics.

Easy fix, put 5.7" rods in it. Or pistons meant for the short 5.565" rods, take your pick. The 5.7" rod way is the better way.

It'll be a slug the way it is now, you gotta correct it.

70-100 hp difference,.... if not even more
MY TYPE OF INFO!^^^ With that being said, is there a certain generation 5.7 rod to use? Are the lt1/vortex rods any different?
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Old 04-26-2014, 07:15 PM
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Quote:
Originally Posted by stevetankl View Post
MY TYPE OF INFO!^^^ With that being said, is there a certain generation 5.7 rod to use? Are the lt1/vortex rods any different?
I personally don't like the late model powdered metal rod and wouldn't use it.

My choice would be SCAT's Prostock rod #2570020P, as they are already "cam clearanced" which is a modification that has to be done to any 5.7" rod when used in a 400 block or 383 stroker situation.

Any older forged stock 5.7" rod you would have to grind/clearance it yourself, Scat's would be ready to go.

Number I gave would be for Press fit piston pins, change the "P" to a "B" if you need to get bushed rods if your pistons are set up to run bushed and you want to use that feature.
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Old 04-26-2014, 08:51 PM
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Quote:
Originally Posted by ericnova72 View Post
I personally don't like the late model powdered metal rod and wouldn't use it.

My choice would be SCAT's Prostock rod #2570020P, as they are already "cam clearanced" which is a modification that has to be done to any 5.7" rod when used in a 400 block or 383 stroker situation.

Any older forged stock 5.7" rod you would have to grind/clearance it yourself, Scat's would be ready to go.

Number I gave would be for Press fit piston pins, change the "P" to a "B" if you need to get bushed rods if your pistons are set up to run bushed and you want to use that feature.
On the grind clearance, is there a certain mill? Can I diy or dose it have to be machined? Any photo of it?
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Old 04-26-2014, 10:34 PM
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Old 04-26-2014, 11:10 PM
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Quote:
Originally Posted by stevetankl View Post
On the grind clearance, is there a certain mill? Can I diy or dose it have to be machined? Any photo of it?
You can do it with a mill, and it can be done with a bench grinder or hand grinder also. It is the area just at the outer edge of the stock bolt head of a stock rod, where the bolt head meets the rod material. Measure radially out from the rod bearing bore to the outer corner of the rod bolt head, and grind/mill to get a dimension of .625" (5/8"). This is on the rod bolt head area that swings closest to the camshaft when the rod is installed on the crankshaft. Requires an ARP bolt with smaller head than a stock GM bolt also.

Here's an article with pictures: 383 Stroker Small Block Chevy - Chevy Stroker - Car Craft Magazine Page 4

The article is about a 383 stroker using 400 crank and 5.7" rods, but the same cam clearance issues are present putting 5.7" rods in a 400...you just won't have the oil pan rail clearance problems with the 400 block, as it was cast for the longer 3.75" stroke crank already.

The capscrew style rod like the SAT 2570020P avoids getting into the rod bolt head when cutting/grinding, and has more clearance because there is no bolt head at that point on the rod.

Lots of images here, look at the stock rod, and stock type capscrew rods at various different photo's : https://www.google.com/search?q=sbc+...2F%3B195%3B179
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Old 04-26-2014, 11:10 PM
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It's nothing there......
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Old 04-26-2014, 11:15 PM
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Check my post #13 above ^^^^
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