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Discussion Starter · #1 ·
I am searching for the best piston and rod combo I can use on my stock stroke 427 BBC. I want to chose a top shelf rod Crower, Carrilo etc. I plan on having a .070 bore but can stick with the .060 bore the eng presently has. I really want to find the lightest combo without sacrificing strength. So far I have only been able to find pistons that will except a 6.385 length rod. They are the KB. 772-70. They weigh 625 grams. They will yeild the 10:5 to 1 to 11:5 to 1 compression ratio I desire. I couldnt find any pistons that would accept a 6.535 rod as I imagine the pin would be in the ring grove. I thought I would ask if anyone new the longest rod with the lightest forged piston combo I can find in off the shelf parts for a 427 BBC .060 or .070 bore. Thanks to all that help I welcome all advice.
 

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Any special reason you're staying with 427 cubes? That's small-block territory now.

Cost isn't much more to go 454 + overbore.

Going bigger than that can get expensive--but--probably worth it.
 

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Your only a crank swap away from 496 cid.The long rod stroker will womp the 438 at a valve train friendly 5500 rpm and live a long life.:yes:
 

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Discussion Starter · #5 · (Edited)
I know, I know. All I started out to do was a piston cam swap. Then a set of 6.385 rods came in to play. Because they are new and for a used price. Plus the piston is lighter than a 6.135 rod piston. Then I thought I would ask the question on rod length before I pull the trigger. I really wanted to draw the line somewere. Before the budget gets out of hand. If I can come across a crank I may have to go for it. If I find a crank. The next thing will be get a dart block so you dont have to machine the mark 4 block to clear the crank,rods and junk the 990 heads for a set of AFR. Believe me it all runs threw my head. Perhaps a brodix aluminum block yea yea thats the ticket. But for now maybe Just a cam, piston and rod swap. Are the 6.385 rods the longest length I can use with an off the shelf piston? Thanks to all
 

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There are a couple of other combo's that might work.

6.535 rods + 1.395 SRP comp height pistons + 1/2 of 3.76"stoke = 9.81"total, or 0.01" out of the hole.

One other:

6.7" rods + 1.270" SRP comp height pistons + 1/2 of 3.76"stroke = 9.85" total, or 0.05" out of the hole. Would require special thick head gaskets such as Cometic.

There might be other piston/ rod combos from other manufacturers that might work, I just looked up Scat and SRP; readily available, not too expensive, good quality.

John
 

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Discussion Starter · #7 ·
Thanks John I appreciate the help. I really would like to keep the compression at the 10:25 to 10:5 with the 120 cc chambers I have now. I will run with 100 octane on the street for now. When I get some more money or sell my 990 and 781 heads,I plan to go to aluminum heads. I then will go to a 114 cumbustion chamber to achieve 11:1. The roller cam I have really should have 11:1 but the steel heads wont let that happen on pump gas.
 
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My Lunati welded forged GM 454 crank stroker 496 rotating assembly w/ my thumb rods dropped into my '75, "TSC" 454 P/U block w/ NO grinding whatsoever.

I honestly figure it will swallow a 4.375" cranked rotating assembly!

pdq67

PS., NOTE!

INSTALL at LEAST 1/4" longer rods for a 496!!!

Save yourself some hassle that I found out about the hard way.

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Discussion Starter · #9 ·
Hi pdq67, I am shopping for a crank. If I find a good deal I will sell my 5140-3.75 stroke crank, the TRW forged pistons and the floated 7/16 SPS bolted rods I have. If in the next 2 weeks, a forged 4.25 crank doesnt come my way I am going to build the 440 cube eng. I will probably use the KB #772 pistons and oliver 6.385 Rods. Then I can have UDHarold grind the cam. I will run the 990 heads for now and swap to aluminum probably the AFR 315 If I sell the 781 and 990 heads. I just want to get the build going in the next 2 weeks or the summer will be over and I will be without a ride again. Life is too short for that. I am going to be out this year!!! I dont care if I have to work three jobs and work on the car in my sleep to do it!!
 
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