I believe bk's 383 is a two bolt block with arp studs and sounds like its holding up fine. You could always go with an shp block, if you didnt want to convert or use studs. If you do convert go splayed as that wont cost much more, arp fasteners and atleast use ductile iron if not billet mains. If you add up the costs youd not be to far off the cost of the shp. You could always buy a used truck block set up for a roller cam already, and save money. It'll set need some machining. Just some food for thought. Good luck with your project.

 

Converting a 2 to a 4 bolt main block was pretty common back when these Blocks were hard to come by and the only Blocks avalable were GM. But now with the advent of after market blocks all this has changed. By the time all the Machining has been done on a Stock Block you have paid for 2/3rds of an after market one. And this dosn't include converting to 4 bolt. If you are building a Motor of 500 Hp or less you can get by with Good Bolts and 2 Bolt. If you are going above 500 Hp you should be useing a after market Block anyway.

 

Does an original 350 4 bolt main have any other different components than a 2 bolt main? thanks..

 

Final attempt to set the record straight-

A) GM did alter the metallurgy on 3970010 casting number blocks at some time during the 70s.

B) Some blocks cast during the same time period have the numbers 010, 020 or 509 cast in various combinations under the cam chain cover.

C) Not all block that have the numbers noted in B) also have the altered metallurgy described in A)

D) Some blocks that have none of the numbers noted in B) have been found with the altered metallurgy noted in A)

Conclusion

1) no consistent correlation can be demonstrated between the 010, 020 and 509 numbers and the altered metallurgy.

Several former GM employees have come forward and explained the relevance of these numbers as being mold or pattern numbers for several different casting number blocks under production at the same time. This has been further substantiated using other examples of blocks cast during the 1960s. In each case, the three digit numbers found under the cam chain cover are the same as the last three digits of the engine block.

I realize that there is zero chance of the 010 020 myth being killed any more than the other thousands myths that have been around twice as long. Did anybody else's uncle own one of the metal bodied Corvettes, or just mine?

 

About 30 years ago I helped a friend build a 350 for his 67 Camaro. He had a nice big shop, but a very small budget because of family etc.. He wanted as hot of engine as he could afford. He had a 350 2 bolt bottom end with a cast crank, and a set of 461X camel back heads. He ordered 12.5 to 1 CAST .030" over pistons, and a solid flat tappet cam, the specs escape me now. I ported the heads, machined them for more lift and push on seals. A used Holley Dual plain intake that was basically a copy of a Z28 manifold with a Holley DP was up top. This combination made for a very healthy 355 that would have seemed to not been the strongest bottom end build. In fact, the whole car was that way. The tranny was a stock 350 with a shift kit and a really cheap 3500 rpm converter. The rear was a 10 bolt with 456 gears.

This car, with used slicks he got for free, ran 7.60's in the eighth, I don't remember the mph. It would leave very hard and lift the front wheels when it left.

The point is he drove this car hard, and raced it some. Nothing ever failed. My friend passed away several years ago, but his family kept the car and all those parts are still in it and it still runs strong.

Not everyone will be so lucky, but the point of my story is that the stock 2 bolt and cast crank aren't as weak as some make them out to be.

 

i can't argue with that, i have seen many cases where "junk" parts worked flawlessly. i have found in many cases where a cast crank or other parts failed it was because something was wrong with that part to begin with, and in more cases it was machined or assembled wrong. when you go to higher quality parts you are only buying insurance.

 

I'll agree with the fact that theres no proof but I do still believe that all the higher nickel blocks out there do have those 3 markings but not necessarily the other way around. some of the blocks only have one or two of the markings... I thing it was the particular batch runs of blocks that had the nickel/tin were always done on the line with the three markings but not consistently were all of them off the line had thet metal composition... they run very large production runs of engines and sometimes they sit for months on end and even get misplaced for months...
MY UNCLE (yes really) worked for a company next door to the one I worked for that shipped engines and parts from the tonawanda engine plant He use to tell me some stories and sometimes I'd see some weird things... for example there was a few dumpsters full of mark 5 engines that had been cut up rendering them useless...
they were from a boxcar that got lost and since the engine run was done they had destroyed them on the spot and had a recycling truck pick them up.
My block just happened to be from a heavy duty 76 chevy 4x4 pickup and the block came from flint Michigan... I read somewhere that the higher nickel and tin and combination of the two were all made in the flint plant.

Another Memorable day was when he told me he had a conversation with a train engineer that day and there was recently an accident where a train car full of new c5 vettes were damaged in a mild derailment of some kind.... The engineer told my uncle that GM had an agreement with the rail company to dig a hole and destroy and bury these cars on rail property since it was in a rural area and even the undamaged cars were crushed for liability reasons... I do believe this happened however I dont know how exaggerated the details of this story were when I heard it.

 

Please read D) above till you understand. Blocks with altered metallurgy were cast at all three foundries not just Saginaw.

I guess there's not enough evidence in world to convince some people.

 

You keep talking about all this evidence yet I haven't seen you produced any more than I have.. if the 010 020 and 509 are casting numbers only than why mark all three under the the timing cover and why do many of the blocks with casting numbers that end in these numbers not have these markings and why do some only have one or two? I'm not saying I'm positive I'm right or anything I'm just saying f from all the hearsay and lack of anyone providing a proven reason to believe otherwise I'm going to do with what most of the machinists seem to agree on.

 

Its been a while... fight. Fight. Fight. Lol

 

Naa... I'll agree to disagree.... he could be right. I wasjust hoping for some real facts to prove his point and prove everyone wrong.

 

Here you go, straight from the horses mouth- at least two guys that actually worked there.

http://www.ncrs.org/forums/showthrea...870-Iron-Alloy

 

Not sure what you call PHENOMENAL but I had my BB done for under $300 and they supplied the GM caps.

Neal

 

Back to the 2 bolt vs 4 bolt issue. Bluedawg has a good memory. My block is a 2 bolt, but with the original bolts. I have ARP rod bolts. I recently had the engine out for a camshaft change. The bottom end looks good after about 200 runs, with 12.17 the best. I put ARP head bolts in now with the roller cam. I plan on pushing the envelope further with it now. We'll see what happens.

 

Nice ill have remember the stock main bolts. Running 12.17 your coming on 450 maybe 475 right? 1\4 mile passes are about as grueling as it gets. Anxious to see what youll turn with the new cam.

 

Any rear end/suspension work?

 

If I rebuild this bottom end I will probably switch to ARP main studs. But for now, based on weight vs 1/4 mile speed and weight vs ET calculators for hp, I was around 400hp. I should have some new track data in a few weeks, if I don't have problems.

 

Not to hijack this thread, but suspension is basically new/rebuilt stock parts. The 3.73 gears, 3,000 stall converter and drag radials really make it leave hard (1.69 sec 60 ft time).

 

Off track, but did you get your hp from weight and et from wallace racing, if so do they use hp or rwhp?

 

Continuing off track - I just google it and I've used several of them, numbers come out similar. They are engine HP. Using 3420 for car (from a scale) plus 180 for me. Estimated HP differences result from using either weight vs ET or weight vs mph (109). In my case, using ET shows higher HP.