Excluding the two bolt mains in 2.30 main web 327 blocks. I wonder how the main web of the block compaired in strength to the later 2.45 main web blocks. With high rpm folks now liking as small as 1.88 honda size pins and the now common as dirt 4340 grade steel cranks made that are considerably stronger steel then the old 1040 and 5140 of the past. Why more stuff not made to use a 2.30 size main.

 

you cant do longer strokes off 2.30 main size, but say a 3.50 stroke would be reasonable to do.

 

NASCAR and road racing benefit from small journal and reduced friction. There is a ratio I don't remember concerning the material overlap of the rod journal to the main journal diameter. As the crossection is reduced there increased risk of failure in a production type crankshaft. The larger journals allowed for less expensive cast crankshafts.

 

Ya but i want my 9 grand street engine lust. Dont want to pay for nascar grafite iron block and billet everything. Just want stout steel cap 2.30 main block with a common today 4340 crank without payi g crower prices. Not doing 9 grand for several hours at a time. Do you know who i can complain to ?

 

Just build up a 68 327 with the medium journal 327 steel crank and the thicker webs and a 4 bolt main. You will have the strongest journal overlap ever made by GM.

OR just build a older thin man 327 and add main studs. It will hold together for long enough.

 

9k lol. There are some better casting I believe were used in school buses. Aftermarket billet caps, studs, and a girdle will hold things together. Oil system requires some help over 7500. Don't complain just whip out the plastic and have it delivered

 

I built a 331 back around 1976 using a large jounal 327 crank in a regular 4 bolt main block, used what almost everyone had those days for pistons forged trw 12.5 ratio, had it in a 66 vette for awhile then built a bbc to replace it. Then gave the crank to a friend he came up with a 400 block so we put it in that block using thicker main bearings, his cu. Worked out to be 348. Just wandering how the old 327 two bolt main blocks main web thickness compared to later 2.45 main web blocks and if you can even buy steel caps today to do 4 bolt main on the 2.30 size main bore of 327 blocks. Eagle would not be my prefered crank to buy but they do have 3.00 and 3.25 stroke 2.45 main 2.10 pin cranks for around $650.00 and i have 2 good 4 bolt main blocks to use with the nodular iron caps. Some of the high end crank builders do the 2.30 main cranks.

 

I would nt worry about how strong it is as you will run out of oil before the webs move around......and unless EVERY passage in the block is opened up, you will NEVER see 9000rpm off of a stock block....it simply will not move enough oil.....and why one would put a $700 crank in a $700 block is beyond me......
Dart and Worlds blocks are LIGHT years ahead in the oiling department......
How do I know all of this stuff? The shop I worked for in 1997 built a 383 that I spec'd with Dart 23 degree raised runner heads and all of the bells and whistles......it made 630 horsepower at 7000 rpm but also wiped all of the bearings out of the "Bowtie" block.........we discovered that the idiots at GM spec'd the oil passages the same size as stock! Our stock eliminator friend, Paul asked us to measure it all out.......he said that a small block is done oiling a 7000rpm and if you get away with anything higher it is luck......so we bought a bunch of drills from Goodson and drilled all of lifter galleys and the main galleys in the rear from the pump and to the cam.....this solved the problem.....
At the time.....Dart was about 8 miles away so when they started doing research for engineering their first Little M block.....they took this data and ran with it as we consulted a lot with them....the GM "Rocket Block" had the larger oiling passages but was dry sump only.......
Paul told me that his 358ci Stock Eliminator block has over $8000 of work in it and about $2000 of it was oiling........Paul launched the car in a wheelie and 1-2 shifted at 8500 rpm in the wheelie......with a four speed trans I watched him run it a few times and to me it was better than Pro Stock!!!! 9.60's from a stock block and heads!!!!!!
Anyway.....if you want to use a 327 block.....you will have to drill it.

Jebby

 

Blocks are free had them both since 70s check out usable mains in spec but would still have them line honed and decked. All my 302 327 builds did 8 grand, factory oil pump, cams and oiling system never changed a thing. in arkansas i was somewhat a friend of for a short time a guy that held e mod production record with a 292 in a 65 coupe. Standing behind the car at the line looking through the back window the moroso cable driven tach mounted where the center speaker once was it was bouncing off its 10, 000 rpm limit. Chevy small block has always had good oiling system. He was first guy i ever knew when doug nash came out with the 4+1 5 speed race trans that had 1. That was big relief to constantly fixing the m22. Those that were not total brand loyalist got rid or the weak muncie swaped in the close ratio bbf top loader. Doug nash really helped chevy guys when he built that trans.

 

For a nice nightmare before you go to sleep tonight, think about the sbc could have been given an OLD.....MOBILE oiling system. I kid you not when i go to a parking lot car show i always carry with me a small roll of black electrician tape. If i see an old-- - mobile owner not around i pull my tape out my pocket and tape over the S on the emblem. One of my jollies in life lol

 

In 72 was at tulsa oklahoma race when jenkins qualified number 1 at 9.39 won the race with a 9.41. That was year jenkins won every race he attended. In later years he claimed in 72 his 331 dynod at 580hp then only 2 years later he claimed the 331 made 680 hp. The only obvious visual difference in the two engines the tunnel ram change and two dominators added. Yet if telling truth he did not win the champoinship in 74. Ford had to carry more weight per cube because of there canted valve head and hemi had to carry even more weight per cube because of there head.

 

I would really question anyone claiming that gen 1stock blocks are oil limited to 7000 rpm

All you need is oil restrictors to the top end. Both my 383 and 396 strokers are running like this for 20 years. It was something I learned from 8600 rpm stock block 360 class sprint car racing.

As to 331 ci motors. Lots of BS as to car stickers throwing off the competition and what the motor actually was. In that era because of head flow limits the large journal 3.25 stroke 4.060 inch. 336.60ci was the hot dog.

 

I ended up only child, would have been 5 year older brother died 1 day after birth and when i was 3 woman crossed over hit my fathers new 53 studebaker head on these were days before seat belts, my mother ended up with histirectomy over that. They both made real good money working for general dynamics father worked on guided missle systems there, aircraft in the air force and for boeing and hughs aircraft before working at GD anyway might give a picture to how i started learning to work on stuff. At 16 they financed me a new 69 Z/28, i was working made the $121 a month payments on it. Now that im through with all this jibberish. As most know it had from factory 254 at .050 duration cam in very small 302 size engine. I can tell you for fact with its 3.73 rear ratio for the 36,000 miles i put on it before buying my first vette 72. I drove the Z/28 to the to 8000 rpm showing on tach for first 3 gears almost always, loved that scream, in 4 th gear would only show 6500 rpm and top out at 135 mph. Small 302 and lousy 69 camaro aero of course causing that. I also built a 454 with for 73 vette ended up with .050 265 dur. Crower it was reved to 8 grand it had over the counter chevy L/ 88 oil pump and screen brazed on and the stock 73 chevy LS 4 chevy pan bolted back on. Both engines had pretty much factory .0025 clearance. I have no good evidence a factory sbc or bbc needs any real oiling mods, i would recomend to anyone pull the cap off the oil pump and braze the pickup tube on it, thats it for any street car no matter what rpm you choose. Is the new shp block stronger, yes better grade of iron used, thicker in places. But the need for the priorty main oiling would not buy it for that reason. If i did go short stroke that is much easier on the lower half of the cylinder case and do 9 grand for short periods of time. Only thing i would do is open clearance to .003 use the new shark tooth melling pump and that would be not truly needed and use a better oil pan, would not mod anything else, short strokes also creat less windage problems. That said building longer strokes the cats me ow for street engines but that longer stroke not 100 percent free would certainly use a 4 bolt main on one even at lower revs engine then nutty stuff i like. Reason that longer arm plain and simple puts more leverage pressure on the lower part of cylinder case and main caps and bolts at all rpms. Theres a reason chevy even though they built both 2 and 4 bolt 400 blocks with the 3.75 stroke the caps are deeper built and look to be wider. There not foolish have to do warranties.

 

It was common practice back in the 60's to bore 283's out to 292 or 301, put in TRW 12.5 to 1 pistons, a 30-30 375 horse 327 cam and run double hump heads. They would spin them to 7000 rpm if not beyond. They were tough little engines. I don't recall any of the ones I knew ever blowing up. We also used to stick the same cam in 283's and zing the heck out of them. I had one I beat the living crap out of that never gave up the ghost. After I got done beating it, we put it in a friends 53 Chevy pickup where it got beat some more. That engine is still in that pickup 48 years later.

Mike

 

Ya the 289 fords would rev like crazy with right cam and fix to head breathing. They had shorter deck block, lighter stuff.

 

I never had any luck with the bored out. 125 over 283 or the small journal 327. They broke the crankshaft just dumping the clutch. That's why gm went to the larger diameter main journals and 4 bolt blocks. The 68 large journal 327 and 350s were the first quality motors

 

I don't know, I never had any problems or new anybody who broke cranks. I broke a few of the 1955 to 1964 style pumpkin rear ends, and a friend of mine was always breaking his trans. Odd thing is I never broke a trans and he never broke a rear end. We both used to run the Borg and Beck clutches. They were a stiff thing to push in and bit hard.

Mike

 

When i pulled 331 out of 66 put the 396 in bought a hays 3200 lb borg and beck. Kept hearing a diapram could over center stick clutch to floor. Kept the hays just did not do that a second time.