Info on main caps

[v6h.o.]

just quickly checked these numbers to give you an idea:

those main caps List price sell for 138$ CANADIAN $, my dealer employee cost on them is about $88 Can.
both caps are within 5$ of each other.

so likely the US$ price on those will be in the 70-100 $ retail price.
GMPD doesnt list those numbers unfortunatly..

one thing i thought of on the topic of the stock blocks not being as meaty in the areas of the main webbing where these extra side bolts for the caps would go into.

would it be even worth it to use a smaller diameter bolt? and use a sleave in the main cap for these extra two bolt holes? or by using a smaller diameter bolt would it basically be moot to even bother with them in teh first place.

i cant remember what the stock cap bolts are ? M12 bolt? so if you used a M10 bolt instead and installed some sort of thin sleave to take up the rest of the bolt hole in the cap for the extra 2 side bolts to keep them all in line and snug would it be worth while doing? at least then you'd have the regular sized two center bolts and two other extra bolts clamping down on the crank to help hold it a bit more.

its always interesting venturing into uncharted territory... i should take a look at the 3400 block i have stripped down at home tonight.

[Corpse]

" cant remember what the stock cap bolts are ? M12 bolt?" - 11MM I believe, same as head bolts. They are actually almost the same length as the head bolts I believe.

-Dave

EDIT: Some more measurements:

Width of cap flang sureface
SBC350: 4.5 (hopefully the 400 will be larger)
660: 4.575

Overall height of cap, bottom flange to bolt mating surface
660:2.275
SBC350:1.98

Just figured I would add these. My numbers are not extremely accurate, I used a Vernier not any type of good measurement tool. It is still not bad for an idea though.

Also, the 660 Main bolts looked a little thinner but, are a hair thicker than the SBC350 Main bolts.

[Nester]

Actually i think the small iron head bolts are the same as the main cap bolts. I remeber someone on another forum working out a deal with ARP to get a bolt set made up with head and cap bolts since ARP does not (as of that time) make a kit for the main caps. I wish i had a spare block and some good measuring tools to really see. While it would probably be ideal to have the same diameter bolts for all four bolts, but i'd think having anything torqued down there would help strengthin the entire assembly, keeping it rigid. The bowtie caps alone are probably more sturdy then the stock ones, billet steel is what they make $3000.00 crankshafts from.

[v6h.o.]

yeah your right they're a M11 bolt... shit i knew that too..

[614streets]

You guys cant phase the 2 bolt mains.

[Corpse]

Well, under normal conditions, it would be hard to make enough power to blow out the mains. More or less, some people running 117 octane and a lot of boost may be worried... Or, the people throwing Nitrous in there engine, or both.

I would assume that, by the fact there were the 383HP Twin Turbo prototype cars, such as the Beretta prototype, that 400HP isn't going to blow your mains.

But, I would assume 400-450 to be pushing them pretty hard. I think that the block would probably start to get hairline cracks in it before a cap were to fail anyhow.

Remember that the main cap is only as strong as what it is connected to.

-Dave

[phantom505]

Let's just say that I have a lot of stuff in work and billet crank is on the list. And for all those people that don't think the 3400/3500 doesn't have enough power will choke on every hanging word. Myself and several others are making HUGE progress to high powered 3x00's.

[Juglenaut]

Manley and Scat use 2.65 mains on some of thier cranks.

I am not sure on the tolerance issues, but I am thinking .005 under from 2.65 is alright.

[pocket-rocket]

You guys cant phase the 2 bolt mains.

Wow, thanks for sharing the facts behind that claim! Maybe it's not just high rpm's, but maybe most of us don't want to be running the car for a season or two before we find out we can phase the 2 bolt mains. Maybe it's a matter of if it isn't too expensive for the insurance, why not take it...