SBC splayed caps

[std]

After reading some old threads, it seems that I can put splayed caps on a 2 bolt 350SBC block. I've never done this myself, so I want to make sure thats what is being said.

So I drill and tap, bolt the caps on, line hone it, and I have a much stronger block. Is that right.

Is one block better then another? I already have an old style rear main crank.

Thanks

[Robert1320]

Re: SBC splayed caps

By upgrading to a Steel cap over the cast cap. Yes you will gain over all strength.
Careful when drill the hole is you go too far you will end up in the water jacket.
If you are doing all this to gain strength do a short fill first, then the caps. So if
you go too far it won't leak and add more strength to the block.

[Robert1320]

Re: SBC splayed caps

'78 or earlier 010 cast for the 350 are perfered.
Properly prepped it can live at 900hp.

[TC]

Re: SBC splayed caps

So I drill and tap, bolt the caps on, line hone it, and I have a much stronger block. Is that right.

No first you bolt the caps on and use the holes in the caps as a guide for drilling the new holes, then you remove the caps and tap the holes.

And technically it isn't going to make your block stronger, it is just going to make the main cap mounting stonger and also since you'll be going to a steel main cap form a cast one it'll make the main caps stronger.

[73Nova]

Re: SBC splayed caps

No its not that easy....You need to bolt up the caps. Use the drill sleeve thats supplied. Drill, clean it out. Tap, clean it out. Bolt your caps back up. Register the holes. Then mildly chamfer. I did this 5 years ago to my 350 and its held up to 8,000 RPM blasts. Also dont freak out when you hit the water jackets. I hit 5 out of 6 on mine. I just used loctite white thread sealer. No problems here......

[std]

Re: SBC splayed caps

Thanks for the info.

I've been machining for years. I just gave the Readers Digest version of what to do.

I think I'll go with the short fill and the loctite. I don't plan on taking it apart again for a quite while. Better safe then sorry.

So how do you think it compares with a regular 4 bolt block?

[73Nova]

Re: SBC splayed caps

I wouldnt fill it...theres no need

[smallblockjay]

Re: SBC splayed caps

My .02

I don't think a short fill would hurt at all and would strengthen the main web. And I believe hitting the water passages isn't the end for the motor. Cylinder head bolts go into water passages. And, yes, head bolts won't leak into the oil pan, but they can cause other trouble.

Two places you can get strength from splayed steel caps. The steel caps themselves, but your gain really comes from the outer main bolts pulling directly on the walls of the block, instead of at a 45 degree angle on the side walls. Also, especially with bigger bore small blocks, your outer main bolts can create weak spots at the bottom of the cylinder bore. With the outer bolts at an angel, pulling in line with the outer walls of the block, you move those bolt holes slightly away from the cylinder bores.

Between having the block short filled and using spalyed caps, I'd say it really ties the bottom end of the block together well and reduces flex.

Just my little &.02

[Robert1320]

Re: SBC splayed caps

Steel caps vs. Iron, that is where the you really gain.
A short fill added in with the steel caps and bottom of the motor should be pretty stable.
Another suggestion, if you are shouting for more than 650hp add front and mid plates.
Beyond that the bores can distort and block damage can occur. I know a couple of guy that trashed blocks after ripping the mounting pads off the block.

[73Nova]

Re: SBC splayed caps

Well 2 guys that obviously know more than me told you to fill it....feel free to fill it. I just said I wouldnt fill it because I didnt and my motor holds together quite nicely, but im only in the 475-500hp area {guesstimate} but if filling works go for it.

[TC]

Re: SBC splayed caps

Ya filling it won't hurt anything, other than reducing the amount of coolant in the block, and big deal if the block doesn't cool as efficiently. At least you won't have coolant in your oil, right. :

Personally if this is going to be a street driven vehicle, I wouldn't fill the block. A good thread sealant will work just fine in keeping the coolant out. And that way the block still retains all of it's cooling ablility.

[smallblockjay]

Re: SBC splayed caps

A street block fill really won't hurt cooling, IMO. Especially if it's a really short fill. Most of the heat is at the top 1/3 of the bore and in the head. A short fill won't effect that. Although I've not done it, my understanding is that you can fill up to the bottom of the core plugs and be OK.

A big downfall to it is it will make the block really heavy.

Just my opinion.

[min301]

Re: SBC splayed caps

Structurally, it's a good thing.

Cooling wise, Cruising shouldn't be a problem.
Really gives em some beef.

[TC]

Re: SBC splayed caps

Cooling may be ok if you have a really good cooling system. But you better have a really good oil cooler to.

[min301]

Re: SBC splayed caps

Agreed. Should be top of the line anyways.