400/512 stroker project begins.

[Heimedw]

Well I got a call from the machine shop today with not very good news. My block is not going to work for my build it has to much core shift on three cylinders? They said you can actually see the shift it's that bad. So the hunt is on again for another block. Is this a common trait and am I going to have a hard time finding a good build candidate? My builder said he would need to see 150 wall thickness and I think that's after boreing.

 

[1967coronet440]

Well I got a call from the machine shop today with not very good news. My block is not going to work for my build it has to much core shift on three cylinders? They said you can actually see the shift it's that bad. So the hunt is on again for another block. Is this a common trait and am I going to have a hard time finding a good build candidate? My builder said he would need to see 150 wall thickness and I think that's after boreing.

I’ve heard the late 70’s motor home blocks were the best for strokers since they typically didn’t see a bunch of miles and weren’t beat on. That’s not to say there isn’t any good other blocks but your luck might be better looking at a later casting.

 

[Heimedw]

I'm on the hunt for one again. Lol

 

[66Satellite47]

FYI, in the mid '80's I sonic checked 8 or 10 440 blocks, '66 to 78. Most were in the .200 - .230 range. A couple in the .180 range. Didn't really see the "thin wall" in the later year blocks. We checked several 400 blocks also. I built 2 400/452 low deck stroker motors. They had .200+ walls also. Seems to me the motor home blocks saw hard use. Never used one though. My first 400 block was a squad car motor, fairly big miles, but they got routine oil changes. That was a good motor that I badly abused with way too much RPM.

 

[Heimedw]

So the machine shop found a block and the gentlemen was nice enough to bring the block into the shop to be tested. They tested that block and it has even more core shift than my block. I have managed to track a fair number of comple 400 engine for fair prices but I will go broke if they all have core shift. I'm starting to get a little discouraged.

 

[Heimedw]

Question is core shift not determined the day the block was cast? I was told that back in the day the worker stood on the assembly line kick the casting into the mould and poured it? If it was off it was off. So if the engine was drove hard or had a lack of maintenance would that have anything to do with core shift?

 

[66Satellite47]

Core shift is purely a manufacturing deal. When I look at a BB Mopar for core shift, I look at the front of the motor, is the cam centered in the casting, are the front cover bolts centered, at the back where are the trans bolt holes compared to the casting. There is always a little shift, but if it's major, the cylinder walls will likely not be good.

 

[Heimedw]

Thanks 66 Satellite.

 

[Heimedw]

So the lastest up date. I found another engine this one was a 77 block. I tore it down and had it sonic tested and it has the most core shift yet. I have had three tested at this point. So I have decided to use the first block and will have three cylinders offset bored. I'm also having my rotating assembly balanced with the flex plate and dampener. The machine shop said they will have it balanced within two tenths of a gram.

 

[66Satellite47]

I built 2 400/452 440 crank motors back in the day. The 400 blocks varied from about .180 to .220. Both of mine ran great. Good power, about 600 HP. Top flite machining is the key to a good motor.

 

[Heimedw]

I wish I could find one that was a min of .180! I didn't get the numbers on the last two blocks but the first had the thinnest point of .147

 

[747mopar]

I'll be watching patiently

I've been wanting more power than I'm getting out of my 456 stroker so with the daughters project coming up I'm thinking about dropping mine into her car then build her 400 into a 512 for my car.

 

[66Satellite47]

My 400 blocks were '72 & 74. The sonic checks showed .180 to .220. I did not fill them. If I would do it again I'd fill them. 4.25 stroke is sure a good way to go. Pick the compression ratio for the type of driving. 10.5 is just fine for street 92 with aluminum heads.

 

[whayden2003]

You say "Id fill them" not sure what this is referring to.

 

[Heimedw]

I think he is referring to stroking one to the max.

 

[66Satellite47]

No, I mean use block filler. I would build a 4.25 stroke 7.10 rod motor. Pistons are a tough choice. Compression ratio depends on the application of the vehicle.

 

[Heimedw]

A little update on the 512. Well today I took a few parts down to the machine shop for the 512 and took a few new pictures. They have the short block almost together. I have all the oiling system parts on order and just waiting on them to come. I did get some bad news. I was told that the mopar bronze destributor shaft has been discontinued?! So what shaft should I use now? Anyway I'm looking forward to hearing all 512ci fire up!

 

[Heimedw]

Pic

 

[5.7 hemi]

Hughes has the oil pump shaft for roller cams, not cheap.

 

[whayden2003]

This whole core shift thing has me scared of my 230 cast 400. My only machine shop option doesn't have a sonic tester.