Block filler for SBC street/strip

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Post Reply
Prostreetbike
Member
Member
Posts: 84
Joined: Mon Feb 08, 2010 8:10 pm

Block filler for SBC street/strip

Post by Prostreetbike » Sun Oct 01, 2017 5:34 pm

I was thinking about doing a short fill to a little below the water pump holes on a SBC 400 street/strip car. I know this may cause me to need an oil cooler, I will monitor oil temp to see.
Is there any pros or cons to Hardblok vs Rokblock ? They seem to be close to the same price, Rokblock being a little cheaper but no big deal.
Has anyone used both and decided which was easier to use or better for some other reason ?
Any one have a preference for any particular reason ?
Any other advice before I go for it ?
Thanks for your help guys.

statsystems
Guru
Guru
Posts: 1084
Joined: Sun Apr 03, 2016 1:17 am

Re: Block filler for SBC street/strip

Post by statsystems » Sun Oct 01, 2017 6:55 pm

If you need to fill you need a better block.

DaveMcLain
Guru
Guru
Posts: 2669
Joined: Thu Jan 06, 2011 8:57 am

Re: Block filler for SBC street/strip

Post by DaveMcLain » Sun Oct 01, 2017 7:05 pm

Hard block isn't that tough to use as long as you mix it according to the directions. I'm not so sure you'll notice any real difference at all with it only about 1/2 full. I think it'll help add durability to a marginal block but how marginal is a 400 block on the street anyway?

prostreetL-78
Pro
Pro
Posts: 280
Joined: Wed Feb 13, 2008 3:35 pm
Location: Santa Cruz, CA

Re: Block filler for SBC street/strip

Post by prostreetL-78 » Fri Oct 06, 2017 2:09 pm

I wouldn't do it. I did a short fill on my old 496 BBC when I freshened it. Honed it .010 larger. The engine which previously ran 160-170 degrees would run at a minimum of 180 and frequently over 200 even with an oil cooler. It was a huge mistake and I ended up building a new engine with a Dart block.

Brent
Galatians 2:20: I have been crucified with Christ; it is no longer I who live, but Christ lives in me; and the life which I now live in the flesh I live by faith in the Son of God, who loved me and gave Himself for me.

ventura74
Pro
Pro
Posts: 206
Joined: Thu Aug 13, 2015 8:22 pm
Location: Il.

Re: Block filler for SBC street/strip

Post by ventura74 » Fri Oct 06, 2017 8:44 pm

Ive always used hardblok on my factory block 383's with no issues.

F-BIRD'88
Guru
Guru
Posts: 5644
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Block filler for SBC street/strip

Post by F-BIRD'88 » Fri Oct 06, 2017 11:33 pm

This is a big waste of time on any street driven engine.

Buy the correct grade Octane of gasoline for the job and the block won't come unglued.
or build with a engine compression ratio that is friendly for the local pump gas.

User avatar
GuysMonteSS
Member
Member
Posts: 198
Joined: Mon Nov 19, 2007 5:35 pm
Location: Nova Scotia Canada

Re: Block filler for SBC street/strip

Post by GuysMonteSS » Sat Oct 07, 2017 6:31 am

prostreetL-78 wrote:
Fri Oct 06, 2017 2:09 pm
I wouldn't do it. I did a short fill on my old 496 BBC when I freshened it. Honed it .010 larger. The engine which previously ran 160-170 degrees would run at a minimum of 180 and frequently over 200 even with an oil cooler. It was a huge mistake and I ended up building a new engine with a Dart block.

Brent
I also short filled my Mark IV block that is 0.070 over and my experience is completely opposite of yours.
It runs no hotter than it used to,and if anything it may even run a little cooler.
I had mine filled to just below the frost plugs.
Been running it like this for the last 4 summers with several highway trips.
Guy
'86 Monte SS,513 BBC,AFR heads,Bullet solid roller cam,Doug Nash 4+1 5 speed,Hurst Inline Shifter,Ford 9 inch Rearend.

kimosabi
Member
Member
Posts: 133
Joined: Sat Feb 22, 2014 5:01 pm

Re: Block filler for SBC street/strip

Post by kimosabi » Sat Oct 07, 2017 6:51 am

There is no reason what so ever that a short filled block should run hotter. When you short fill you're only stabilizing the bottom region and take away some room for coolant around the bottom of the cylinders. Oil, from the other side, works as a heat transfer down there. Crankcase temps are usually hotter than the coolant so what you're doing when short filling is you isolate alot of coolant from a hot crankcase. I would prefer a good oil cooler when shortfill though but many times you don't need one.

plovett
Expert
Expert
Posts: 585
Joined: Sat Dec 30, 2006 3:49 pm
Location: Kansas City

Re: Block filler for SBC street/strip

Post by plovett » Sat Oct 07, 2017 8:48 am

F-BIRD'88 wrote:
Fri Oct 06, 2017 11:33 pm
This is a big waste of time on any street driven engine.

Buy the correct grade Octane of gasoline for the job and the block won't come unglued.
or build with a engine compression ratio that is friendly for the local pump gas.
This makes it sounds like the only reason anyone would ever put block filler in a block is if the compression is too high and/or the octane is too low. I think there are more reasons than possible detonation that someone might want to add support to the block.

JMO,

paulie

dwilliams
Expert
Expert
Posts: 921
Joined: Sun Oct 15, 2006 10:00 am

Post by dwilliams » Sat Oct 07, 2017 9:47 am

I've done various FEs and Clevelands. The sonic checker said the tops of the cylinders were okay, but several of them were very thin at the bottom. None of the owners reported any oil or water temperature issues in service.

F-BIRD'88
Guru
Guru
Posts: 5644
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Block filler for SBC street/strip

Post by F-BIRD'88 » Sat Oct 07, 2017 4:32 pm

plovett wrote:
Sat Oct 07, 2017 8:48 am
F-BIRD'88 wrote:
Fri Oct 06, 2017 11:33 pm
This is a big waste of time on any street driven engine.

Buy the correct grade Octane of gasoline for the job and the block won't come unglued.
or build with a engine compression ratio that is friendly for the local pump gas.
This makes it sounds like the only reason anyone would ever put block filler in a block is if the compression is too high and/or the octane is too low. I think there are more reasons than possible detonation that someone might want to add support to the block.

JMO,

paulie
You are trying to put a "spin" on something that is not there. What I am saying is spend your money on what matters and will make a difference.

Many many guys tend to build with a excessive high cr for the fuel they will be buying.
Then they blame the block when bad things happen or come up with some cure like block filling
when what really is needed is correct fuel.

chevy 400 blocks are not weak in the lower water jacket area.
Where they go is on the decks between a head bolt and the lil steam holes.
Often a small crack here does not leak or effect performance.
Just looks bad. Some drill and tap the lil holes for threaded plugs
to strengthen the steam holes.

Block filling is not needed on any street 400 SBC at all.
Spend your money on stuff that makes a difference like cylinder heads and high quality gasoline ( high compression)

plovett
Expert
Expert
Posts: 585
Joined: Sat Dec 30, 2006 3:49 pm
Location: Kansas City

Re: Block filler for SBC street/strip

Post by plovett » Sat Oct 07, 2017 5:35 pm

F-BIRD'88 wrote:
Sat Oct 07, 2017 4:32 pm
plovett wrote:
Sat Oct 07, 2017 8:48 am
F-BIRD'88 wrote:
Fri Oct 06, 2017 11:33 pm
This is a big waste of time on any street driven engine.

Buy the correct grade Octane of gasoline for the job and the block won't come unglued.
or build with a engine compression ratio that is friendly for the local pump gas.
This makes it sounds like the only reason anyone would ever put block filler in a block is if the compression is too high and/or the octane is too low. I think there are more reasons than possible detonation that someone might want to add support to the block.

JMO,

paulie
You are trying to put a "spin" on something that is not there. What I am saying is spend your money on what matters and will make a difference.

Many many guys tend to build with a excessive high cr for the fuel they will be buying.
Then they blame the block when bad things happen or come up with some cure like block filling
when what really is needed is correct fuel.

chevy 400 blocks are not weak in the lower water jacket area.
Where they go is on the decks between a head bolt and the lil steam holes.
Often a small crack here does not leak or effect performance.
Just looks bad. Some drill and tap the lil holes for threaded plugs
to strengthen the steam holes.

Block filling is not needed on any street 400 SBC at all.
Spend your money on stuff that makes a difference like cylinder heads and high quality gasoline ( high compression)
O'tay! ;)

Post Reply