Hey I did a search didnt find much... I was thinking of my 454 rebuild and I was thinking the idea of putting 4 bolt caps on. Is it worth the money to do this? Or is it not worth it unless I used aftermarket caps? I see plenty of stock caps on ebay for cheap I think. Has anyone done this here? I want to push 650hp one day.
just give me your thoughts. Thanks.

You can push 650 with a 2 bolt BBC....just use main studs instead of bolts, or at least ARP main bolts. IF you wanted to still do a 4 bolt main, you might as well spend for the splayed caps which are stronger.

My thoughts are I can't wait till you get "something" built.

But to answer your question, I converted the blower motor from 2 to 4 bolt caps. The cost of the caps was $30, at this point you will have to decide if your using studs or bolts. Then the block will have to be aligned bored. You'll have roughly $200+ in the cost of the studs/bolts and align bore.

For what your doing though, a 2 bolt will probably hold up fine, unless you want insurance.




[This message has been edited by BlownBigBlock (edited January 07, 2005).]

<font face="Arial,Verdana" size="2">Originally posted by BlownBigBlock:
My thoughts are I can't wait till you get "something" built.

But to answer your question, I converted the blower motor from 2 to 4 bolt caps. The cost of the caps was $30, at this point you will have to decide if your using studs or bolts. Then the block will have to be aligned bored. You'll have roughly $200+ in the cost of the studs/bolts and align bore.

For what your doing though, a 2 bolt will probably hold up fine, unless you want insurance.


[This message has been edited by BlownBigBlock (edited January 07, 2005).]</font>

whats with that? Cant a guy have more projects than he can handle? some of you guys sound like my wife http://www.nastyz28.com/ubb/redface.gif

[This message has been edited by badazz81z28 (edited January 07, 2005).]

I bought my 4 bolt main block for $250 seems like that would be a easier way to go. About a 1/3 (just a estimate) of all power units are 4 bolt mains. I am told some even have forged cranks. Was going to buy as many as I could used and part them out but don't know about the demand.

I agree with the guys - keep the 2 bolt and go to ARP studs. I have about the same setup and my engine is holding up fine. Save the money for something else.

i think 2 bolt with arp studs would work for you. i dont think splayed mains arent cheap.

The factory 4 bolt caps are the way to go here, especially if you build an external balanced engine, you can experience cap movement with lots of RPM and an external balanced crank such as a 454. You can find the 4 bolt caps off a 366 or 427 tall deck truck block. The big block main webs are the same between the 2 and 4 bolt blocks and they are plenty tough. A properly chosen set of used caps, aligned to the factory line bore, outer bolts drilled and tapped, requires no more than an align hone, .005 to .008 total material removed, shifting the crank centerline up half that distance.

We have a blown alky 427 that runs bottom 7's in the quarter in an ex TAD chassis. 30 lbs boost, 10.5:1 compression, occasionally hits 9000+ RPM on the burn out, nothing fancier than a factory 4 bolt block (filled) with ARP main studs. ZERO cap movement! (Factory 366 crank too) Roughly 1250 HP, guess GM had it right when they designed the big block.

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Custom Auto, your source for quality machine work, cores and new parts at competetive pricing right here in British Columbia 1-888-563-4050
A Canadian, EH? (with a 10 second street car)

with that alky 427, is that a stock block like not after market? Cuz i've herd and seen the results that gm big blocks only hold up to about 1000HP then the main webs start cracking and breaking off.

just courious

Factory block, bearings looked great

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Custom Auto, your source for quality machine work, cores and new parts at competetive pricing right here in British Columbia 1-888-563-4050
A Canadian, EH? (with a 10 second street car)

HMMM interesting. i got a friend that used to run a stock bigb block and was running in the 7's with 1300HP and he went through 2 blocks before he even figured out what was goin on. now he rund i think the world castings block which is heavier but well worth the extra weight.

The clue here is the 427 stroke, 3.76. Internally balanced from the factory, counterweights in the right places. If you're friend is spinning an external balanced assembly, longer stroke, or running into detonation you WILL have block failures at the higher horsepower levels.
The Merlin 3 blocks we have used sofar are very nice, super beefy cast iron caps, doweled, as well as monster thick cylinder walls. Heavy but nice. I think the ultimate big cube engine for a reasonable budget would be the 427 crank and a 4.600 bore, working out to 500 cubes of near bulletproof big block.

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Custom Auto, your source for quality machine work, cores and new parts at competetive pricing right here in British Columbia 1-888-563-4050
A Canadian, EH? (with a 10 second street car)

ahh i see now. i can;t exactly remeber if his was externally balanced or not. Probablly was. i know that he didn't have detonation problems the couple times he chunked the blocks. seemed like both times they broke he was running perfectly and was on the way to winning the class.

oh well good to know thanks for the info.

no sweat! http://www.nastyz28.com/ubb/smile.gif

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Custom Auto, your source for quality machine work, cores and new parts at competetive pricing right here in British Columbia 1-888-563-4050
A Canadian, EH? (with a 10 second street car)