Hi "Stroked", IMHO......YES, definately HARD BLOK! This becomes really important when you start boring oversize as the cylinder walls begin to get thinner and thinner (big "DUH", right! :grin: ). HARD BLOK First off......I would have the block sonic checked to absolulely know the thinkness you are starting with. You can do a visual and look for obvious core shift by looking to the lifter valley. You will be able to see if the lifter bores are centered or offset and that is a very good early indicator of whether the cylinder bores are in the same condition or not. The HARD BLOK, TA main girdle and such really start to become a necessity once you near the 550-600HP mark. What bore are you thinking of going with? I ask and believe the above because I've seen blocks with cylinders that have gave away with as little as a .038" (4.350" bore). On a brighter note.......I've bored a few as big as 4.375"! Talking with Mike Tomeszeski (TA Performance) before he has bored as big as 4.385 & 4.390. That was a couple of years ago at the 2000 GS Nat's we had that discussion. COOLING I've regularly driven a 723HP 1050 Dom. Stage3 464ci (4.350") in the middle of the hottest Central IL days with no cooling problems and no aluminum radiator, just a Modine 4-core. I believe this alone did not keep the engine cool, but the fact that I run a 13-14 qt. oil system helped tremendously in relieving the heat! In town, stop-n-go traffic would net me barely over 170* water temps. The oil would run in the 180-190* range. Also making sure the fan (5-BLADE THERMAL no less!) was properly placed 50% in/ 50% out and centered in the shroud. Completely seal ALL gaps around the shroud to force a low-pressure area there. At idle I could take a piece of paper and put it on the back side of the grill and it would be sucked to the radiator QUICK! EASE OF POURING A good article in the September issue of HOT ROD magazine page 68-69 gives a photo by photo of adding HARD BLOK. Ckeck it out......if you can't find that article/issue let me know and I can send you a copy. Hope this helps...... Oh, BTW........From now on please be sure to add at least your first name to you posts, PLEASE!:TU: We like to know who we are talking too.
Thanks. Kerry, Thanks for the help. What year blocks were you using to bore that large or were they random? I got a late 72 engine so its got the double hump block. but the casting numbers were late 72. Dan H.
Heed Kerry's words carefully as far as oil temp goes. I also have a filled block and tried to run with stock pan and oil temps are too high under slightly extended loads. It'd be fine for the strip, but not driving on the street. Like Kerry my water temps are just fine, but you gotta be careful with your oil setup. Also, oil coolers are not the ticket with a Buick unless you really know what you are doing. The marginal oil system doesn't like the added line losses and re-fill volume associated with the cooler & plumbing. I learned this the hard way and Mike T @ TA confirmed it. HTH
i might sound dumb, but what the hell is a hard block?? i think i'm getting a idea from the thread. not sure. Still learning guys. p
Hi Dan, The common thought used to be that there were two distinct 455 block designs but actually there were three. The first was the single scallop round hole block and heads (1970-71). Here's a pic...... BTW......this is the '70 "SR" block that has just recently been bored .0625" (4.375") and O-ringed for a little "juicy-juice" later!:grin:
I believe in either late '71 or early '72 then went to the double scallop round hole block/heads. Here's that pic.....
Here's the third, late '72 and up block design with the double scallops and oblong holes. Here's that pic....... notice that this is a '75 block that you can see the HARD BLOK if you look closely. This was the engine that I mentioned earlier that made the 723HP and would barely run a water temp of 170* on the hottest days. Unfortunely if you look closely at the lifter bores you can see some that are only half there now! Needless to say this is now a "mock-up" block and that's about it. :ball: If you go back and look at the first picture you will see that I've filled the lifter valley of that block for this reason.
Also Dan....... The '75 &'76 blocks are about 11lbs heavier than the previous years were so those are usually the best years to use! BUT.......I've found several random years (thru the sonic check I mentioned earlier) that can take the "big" over bores also. It all comes down to checking it out thoroughly first. Besides the I '70 "SR" block above I have done another 1970 block, a "SF" coded, that took a .060" overbore (4.3725") quite nicely too. Like I stated earlier a visual look-see of the possible core shift of the lifter bores will give you an early indication of whether to even spend the money for the sonic check (usually around $75 or so). You want as much wall thickness as possible on the thrust-side of the cylinder wall (this being the the side that is towards the drivers side as we have clockwise rotating engines). Hope this helps......
Hi Albert, HARD BLOK is basicly a manufactured iron particle based concrete mixture that is used to "stiffen" the cylinder walls to give them the extra support they need. This helps to reduce or eliminate wall flex that can cause ring sealing problems and so forth. It's also used in "our" Buick's case of suffering from the "thin wall casting syndrome" to help support the walls so we don't just blow them out from the massive cylinder pressure some of us tend to build toward!:TU: If you can go out and buy the September 2002 issue of HOT ROD magazine on the stands now. It has a good two page article w/step-by-step colored pic's of the HARD BLOK install. Hope this helps......
