Hardblock?
 

I have a set of S/S 350ci chevy pistons + .060''....should I hardblock fill my 010 block to support that large an oversize? wondering about the extra weight too...tks.

Re: Hardblock?
 

Most replies are going to favor the hardblock procedure.

Re: Hardblock?
 

Yes

Re: Hardblock?
 

Absolutely. In fact, you should probably have it thoroughly sonic tested. The majority of those blocks are really marginal at that over size.

Re: Hardblock?
 

alan even if its thin, would the filler not still support it? so the thicker the better...fill the thickest one?

Re: Hardblock?
 

Sonic test first and at that bore plate honing is a must to achieve good ring seal.

Personally i don't find many OEM blocks that would be a good build at .060 over. Like I said sonic test first.

Re: Hardblock?
 

Do you use a half fill or a full fill? Do you put a gasket and head on after filling that side of the block so the bores are distorted in the same way as when running? I was thinking of buying the full fill Hard-Blok and then using half in my 273 Mopar block (and 1/2 of that on each side). I've never used this before, but the cylinder walls on the 273 blocks are under .200" thick, some down around .130" with a standard bore. The cylinder walls tend to be thinner in the middle and the front and rear areas between the cylinders.

Re: Hardblock?
 

.130 at Std. Bore is rather thin.

Might be worth checking a few more blocks.

If that is on thrust side I personally would not like to us that block.

Suggest filling it to within a inch or 1 1/2 to top of water passage if
I did use it.

Re: Hardblock?
 

Do what you want, but I wouldn't hard block anything. Did a 0.060 over 283, and a 0.030 327, and if you could watch the shaking of the stones when rehoning after teardown, versus ones being honed without any hardblock, you'd know what I mean. They never, ever, stayed round. And everything was done with two torqueplates, mains, and pump installed. I have never used it since.

Re: Hardblock?
 

If you had the choice , wouldn't it be better to start with a good block , like a Bowtie or Dart ? A filled block has other problems like bores going out of round , or cooling problems when racing . What does a filled block weigh , compared to a Bowtie block . Plus after you where it out for bore size , it can be sold to someone that can use a bigger bore size . In the long run it might not really cost more to run a good block .

Re: Hardblock?
 

John, I've attached the sonic check of the three 273 blocks I had sonic checked in January. The "orange" block checked worse than the "greasy" and "rusty" blocks. None of them were all they great. I think I will build a 2bbl engine with one of them, save the best for a 4bbl engine after I get my feet wet (hopefully not literally) with the 2bbl engine on building Stocker engines.

Re: Hardblock?
 

Im trying to build a "seat time" unit togeather. bowtie or dart is not in the budget. using pistons from the 80's w/low runs. what did everyone do before filler came along? thankyou everyone for your input, keep them coming...

Re: Hardblock?
 

Years ago a stocker was only allowed .035 over. The stock blocks were pretty good at that size. Now with the more overbore the need for block fill or the better aftermarket blocks is needed. I personally have not had good luck filling the stock blocks and running at .060 . several have cracked the cylinders. You will be much better off to save a few bucks and get the aftermarket block. They are much stronger in the cylinder walls and deck. The bores will stay round and straight. The lifter bores are also very accurate on the aftermarket blocks. Believe me it will be money well spent. I wont even fool around with stock blocks any more and its real hard to find the older 4 bolt main blocks that are the best.

Re: Hardblock?
 

It seems that all the 273 blocks are a little thin, the 67-68 i have found are the worst, i had to fill my block.

Re: Hardblock?
 

do we fill the bowtie/dart blocks?

Re: Hardblock?
 

No need to . A 4.00" Bowtie block can be taken out to 4.160" and still have a nice thick wall .

Re: Hardblock?
 

Very good advice Mike....there is no saving $$ in drag racing ...purchase a bow tie block, it will last you forever.....do it right the first time, you will be glad you did.....

Re: Hardblock?
 

Didn't know there is a bow tie block that matches a 273 Mopar.! Oh! The curse of trying to make 50 something old run with modern stuff.

Re: Hardblock?
 

I guess the real cure without buying a 3K block and getting thick walls, would be to sleeve a 318 to 273 bore size

Re: Hardblock?
 

I believe a Dart SHP block is less than $2000. There is also the money you will spend on the stock block you will not have to spend on the after market block. Filling, cleaning, checking... So that cost can be deducted off the price of an after market block also.

Re: Hardblock?
 

My engine builder wanted to get a standard bore 340 block and sleeve it down to the 273 size. If I wanted to build a killer 273, then I'd do that but I want to keep the costs down. It quickly looked like a $20k engine if he was going to build it. I don't think an R3 block would be that much better since it would still need to be sleeved down.

It looks like I should have started a separate thread on the 273. I thought the hardblock info would carry over between the brands, but it looks like things got corn-fused.

Re: Hardblock?
 

No.

Re: Hardblock?
 

I agree with you 100%.

Re: Hardblock?
 

hey... we all want a good block !!!

Re: Hardblock?
 

Save yourself the aggravation, I hard blocked my 010 block and went .060. With new cp pistons. After the 1st pass the car slowed down. Made about 20 more runs on it. Tore it apart this winter and the cylinders where .008 out of round. And my new pistons skirts where scuffed really bad. Do yourself a favor and just get a SHP block and be done with it.

Re: Hardblock?
 

Best advise ever !!!!!!

I was going to post that as I have seen what you observed with your build but most think I post that to sell new blocks.

Re: Hardblock?
 

You can buy an SHP block all machined and shipped for that kind of money.

Things that should be addressed when having one of those blocks machined.

– Main housing bores chamfered
– Freeze plug holes and rear cam hole are chamfered
– Line honed to at least the middle of the spec or high side if needed
– Decked to your demension
– Bore to your spec
– Plate honed using the same gasket and hardware that will be used in the end build
– Lifter bores checked and honed to the lifters that will be used in the end build
– Top of lifter bores chamfered
– Bottom of the cylinders chamfered
– Tap oil galley holes deeper
– Chamfer Distributor hole for O rings.

Re: Hardblock?
 

that is great advice for chevy people, how about small block mopars?

Re: Hardblock?
 

Those blocks are hard to come by .

Check with Ray Barton

Re: Hardblock?
 

I use Halco Machine Grout in the BB Chryslers and never had any out of round issues. Is the Hardblock the issue or is it because the Chevy blocks are softer and maybe thinner. I'd love to have one of the new aftermarket BB Chrysler blocks avail but at 4K that probably wont happen. I use the 413 industrial blocks for my 63 and they are about .300" before machining but filled a standard 383 block for my Challenger about 3 years ago and haven't machined it yet so I think it's cured by now. How long are the people who had trouble with the Chev's waiting before machining.

Re: Hardblock?
 

and at over 3K

Re: Hardblock?
 

Any special preparation needed before HardBlok? Is the standard hot tank good enough, or does it need special rust removal to get a good bond to the iron? I'm thinking muriatic acid inside with a water flush. Maybe follow with Evap-o-rust or is all of that overkill?

Found this online.

http://dalhems.com/f/d/808c931833604...str-022005.pdf

Re: Hardblock?
 

The muriatic acid cleaning is an excellent idea. I don't use anything after that except a flood of good clean water.

I bolt a head to the opposite side of the block, and torque the main caps. Then I pour the first side, and immediately install a cylinder head and torque it. I let it set one week. Then remove the head on the other side, pour that side, reinstall the head, and let it set another week.

Re: Hardblock?
 

This guy found the same thing I found out.

Re: Hardblock?
 

If you want the best, use MasterFlow 885, formerly known as Embeco 885.

MasterFlow 885 has a metallic aggregate, it is non-shrinking and way stronger than HardBlock or the Moroso product after cured.

Re: Hardblock?
 

My rule of thumb if you have to fill the block your using the wrong block,


Cylinders change during heat cycles and and never come back to the original machined size.

Re: Hardblock?
 

So every combo that can not get an aftermarket block should just stop building engines. That is what you are basically saying

Re: Hardblock?
 

Which engine wòuld that be?

Re: Hardblock?
 

go look at the replacement blocks listed by the nhra, and try to find some of the rarer combo's. This idea having to run a replacement block and spend vast amount of money to compete will be the nail in the coffin for many people.

Re: Hardblock?
 

I have never experienced any of the out of round problems.
Over the last 30 years I have filled blocks for Circle track, Drag and mud racers as well as boat racers. A few years ago I took a late mod 305 and filled it and bored it to std. 283 for a boat race class. Freshened it once and I think it is still going.
I use a Machine grout and I let it harden at least a month before doing any machine work. I also increase the Piston to wall clearance by at least 40 -50 % . I always test piston growth before deciding on the final cold bore clearance. A water block cylinder moves, a filled block does not and the pistons still grow with the hot oil and combustion heat on them.
Allow for it. On the circle track Applications I only fill to the oil galley holes in the lifter bores. My theory on that is still have water in that part of the cylinder to pull heat out of the oil going through the lifter galleys.
Seems to keep oil temps in check.