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#21
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feel your pain.. had a crank break in half a couple years back...not a good sound to hear. good luck
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1970 firebird, 468, e heads, |
#22
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How many Ponty engines you got?
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#23
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If you can AFFORD to be out of your comfort zone then good luck to you..
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#24
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I have a 67 400, and a stock complete 70 455. So have those to choose from. Also just picked up a 57 Pontiac rear with 4.10 posi that has some value to help fund this. . If i could would want an aftermarket block.
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Illinois Outlaw Gassers 6.27@107 9.97@131 |
#25
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If that 67 400 is a 2 bolt, non drilled put some splayed billet caps on it. They are the best 400 block short of a RAV. Real thick bores. you can take them .090 + (with sonic check)
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#26
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SO are you telling me that a 68 400 block is not as good? Why? But the 68 heads are better, right?
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#27
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With either of those blocks I would say that you should install Steel main caps on them if you can afford that whole process.
If not then I would build the 400 due to its lesser main Bearing speed and meatier main caps even if there only 2 bolt. If you take the hour and a half worth of time to polish over all the sharp edges on the factory 1 thru 4 main caps but for each caps Bearing parting line it will be a lot harder to just out and out crack them.
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#28
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The 67 400 is a 2 bolt and was looking into splayed caps. It needs a sleeve or could just overbore it some. After a sonic test to see how thick it is. A stock wristpin got loose and wore a small groove into the bore.
Im thinking the 455 was like mine and drilled for a 4 bolt but only has 2 bolt caps. Could also put straight caps on the center 3 if so. How big of a difference between splayed and straight for strength? I was going to put in the longer locating dowels as well.
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Illinois Outlaw Gassers 6.27@107 9.97@131 |
#29
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Splayed is way to go Bill.
The caps reach right out to the pan rail. I did a set on a 400 2-bolt block.
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Carburetor building & modification services Servicing the Pontiac community over 20 years |
#30
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Quote:
Dan Whittmore told me all this and he was in with the GM engineers. BTW, I grew up with a 66 Catalina station wagon. It finally died due to cracking a bore. It was the block Marty P chose to put twin turbos on and make 1400 HP back in the day. I have one and it is .060 with pits in 2 holes. I will take it .090-.100. |
#31
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Quote:
Do you remember your main and rod bearing clearances? SD |
#32
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Looks like crap, lol. Main caps were walking. The main cap that broke with the bent bolt bent the dowel pin some too. I visibly dont see any cracks , but a git was taken at the outer main cap bolt . Maybe fill that in with another allen head bolt and loctite it in?i did hone cyl 4 a little bit. Rod 4 was the only one that spun. So it wasnt.a feed issue, cyl 1 looked good.
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Illinois Outlaw Gassers 6.27@107 9.97@131 |
#33
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Quote:
Replace ALL the dowels. Since its already drilled for 4-bolt mains, get the non splayed 4bolt main caps (Program Eng) Bore to next size that cleans it up rebuild with lighter weight rotating assembly that will live & 7,000 RPMS! Then install a two stage rev limiter for burn outs and red line! You may want to check the classifieds, George is selling a set of 6.7" aluminum rods for a song and a prayer... I would have picked them up if he was selling them 2 months ago. SPEED SAFE, NICK
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"The grass is not greener on the other side, its just fertilized with different $h!t" |
#34
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Update, so the block is not cracked. I have some extra main caps in can see how centered they are, plus a new main stud. I was also going to use the longer dowel pins that Precision automotive sells to help with the cap walk
. Than can get a forged crank, rods and 5 of my pistons are usuable. There is still some visable damage closer to the bottom of the cylinders and can take out the high spots getting it honed out http://www.precisionautomotivespecia...ine-Parts.html Or just do the 400 block and splayed caps for quite a bit more money and build from scratch.
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Illinois Outlaw Gassers 6.27@107 9.97@131 |
#35
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Quote:
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“It takes considerable knowledge just to realize the extent of your own ignorance.” Dr. Thomas Sowell |
#36
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I have 2 from a 428 block. I have to remove the bent dowel on #2 and see how it fits, centered wise. I realize only 2 and 3 will work. If these do t.work, may go ahead with the 400. I see people selling stock 4 bolt caps on here and never hear about issues getting them to fit?
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Illinois Outlaw Gassers 6.27@107 9.97@131 |
#37
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People sell caps all the time, but they don't have to make them fit, either. Pontiac caps are difficult to fit because of the way they are retained. Blocks that use register press to retain the main caps are easier to fit, since you can weld the side of the main caps to adjust their fitment to the main saddle. With Pontiac caps, you normally have to radically cut them (as in .030-.040 or more) to get them to align with the main saddle. I've align bored around 6,000 blocks. I've replaced the caps and align bored 1,500+blocks. It's never as easy as you're assuming it is. I'm just attempting to save you headaches and wallet aches....
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“It takes considerable knowledge just to realize the extent of your own ignorance.” Dr. Thomas Sowell |
#38
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Go steel main caps
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1965 TriPower GTO, 1967 GTO, 1969 GTO, 1969 Judge, 1972 GTO, 1977 Smokey and the Bandit, 1989 TA ProStreet, 1968 Firebird NHRA 10.90 racecar, 1963 Tempest S/Gas |
#39
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Thanks for the info. ill drop the caps off today and if they don't work will decide from there.
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Illinois Outlaw Gassers 6.27@107 9.97@131 |
#40
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Good plan
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“It takes considerable knowledge just to realize the extent of your own ignorance.” Dr. Thomas Sowell |
Closed Thread |
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