Drtmod5

This one is a 511, 3 freeze plugs as you said. The 3 main caps have 4 straight holes, but only the inside ones have threads for bolts. The guy I got it from couldn't find the original main caps for it, so I would have to find those also. I have 2 more 350 4 bolt blocks in my shed. I'm leaning toward another 383 build.

Tod74

now that I think about it, I believe I read somewhere the 511 block came both as a two bolt and a 4 bolt...just like any other casting number....duh. wasn't thinking.

DRTRCR22

I acquired a stock bore 4-bolt main 511 casting engine from a junkyard. I was also concerned about building on this block foundation from what I have read from others here, so I took it to Greg Stafford at Stafford Performance - Car Parts Machine in El Paso Texas, who is a top notch circle track race engine builder. I asked him to sonic test and magflux this see if there were ANY questions about it's ingerity, and his honest opinion about using this block. He frowned and squnted a bit at first, but said he would investigate it thoroughly. He called me after investigation and told me that he finds this to be a good and solid crack-free block that will go .030 overbore and would have no concerns building this for himself for racing. I then had him plug the steam holes and do all the decking and machining he would do for a complete "race-prepped" block. I then had him balance a 392 rotating assembly I already had (4.145 bore x 3.625 stroke x 6" rods) with very small dome slugs. I asked him to keep compression mild to prevent any wall fractures or overheat problems. He machined and rebuilt my 64cc World Product heads, which left it just under 12 to 1 compression. I have run this engine HARD many times at up to 8K rpm on a flat tappet (JR109) cam and have never got it over 170 degrees on alcohol. Of course alky keeps things cool, but I have zero concerns for this package. I guess maybe I just got lucky, or maybe it is a calculated risk by asking an expert his honest professional opinion if it is worthy or not.

zipper06

I've got a 511 blk in my Malibu with 2 bolt mains and 13.5 pistons and 377" i've even welded the side of the blk about 4" crack just below the deck and put close to 150 passes on it with alcohol, no problems so far. I also have a 511 4blt main on the engine stand for a 406" street motor. If i had my ratheres they would both be Dart blks. But thet are what i have.
My main concern would be with the mismatched main caps that you have on your blk. That means line boring and tapping the extra main holes, it will cost you money to run this blk. for sure.

JMO

Zip.

cncmotorsports

Dave, Save your self the money and buy a Dart SHP block, by the time you add splayed caps and all the other machine work you will have more money in the block than a SHP block is new.

We build a few UMP engines, they all get aftermarket blocks. Saves you money in the long run

kwkracing

Did he pay you to haul it off?

No, main caps, no good!

JEFF69Z28

I RUN A 4 BOLT 406 CHEVY BLOCK SHIFTING AT 7200 AND GOING THRU THE TRAP AT 7500 FOR THE LAST 3 YEARS WITH NO PROBLEMS UNTIL NOW AND I THINK IT IS A OIL FILTER PROBLEM.

TheYellaBrick

AAAAKK!!!!!!!!!!!!!! It's not a FRAM is it ?!!!! ops: ops: ops:

JEFF69Z28

Yes it is im scared to drain the oil, im afraaid ill find what i dont want to find.if there is no metal in there im putting on a wix and going racing one last time this year,hopefully it wont be this motors last.