Block Fill

[SilverBulletZ28]

I am just getting back into performance cars after a few years off...

Was talking to an engine builder and he suggested a "partial block fill" when building a 383 small block. Now I am aware of a totally or mostly filled block for drag only, but this is a street motor.

Any thoughts? Durability?

Much obliged...

SBZ

[Twin_Turbo]

you can fill it to the freeze plugs no problem, the vast majority of the heat is produced in the top of the cylinder bore. The block rock won't make it run hotter at all. Durability will be severely increased as the cyl. wall is much better supported. I've never had probs with it, just fill 'er up before doing the machinework (when it cures it does distort the block somewhat)

[MonzaRacer]

You will never need block filler on the street. IF you need that kind of reinforcement then you need to purchace an aftermarket block.
Besdies you can buy World block of one of the Bowties and have a better block with less work and never use block filler.
As for Hard block distorting a block it doesnt swell or shrink as it has a base of pure cast iron. To prove my point if it swelled when I filled a coke bottle with it it would have split the bottle.
BUT if you are makingthe kind of power that requires block filling you need a tall fill or an aftermarket block.
And this is from a machinist.
Lee

[Twin_Turbo]

I have to agree with you on the aftermarket block comment. However if you can't afford the aftermarket block the block rock is a cheaper alternative (although not near as good).

As for the swelling shrinking, you can't do a test on a coke bottle, this is about tolerances in the thousands but be my guest, have a block fully machined, bored and honed..use torque plates all you want, then fill it with block rock and see if you have a prefect sealing bore. This amount of distortion is very small, so the whole coke bottle deal is moot (and glass is actually capable of plastic deformation)
Detail oriented builders even use the fasteners to be used on final assembly during machining to mimic the case distortion, it all helps with getting the best sealing bores possible...and you test it with a coke bottle....right!

[myclone]

A GM street motor that is filled to the bottom of the freeze plugs will be fine as far as cooling is concerned (there are quite a few turbo'ed V6s running around on the street at this moment with partial fills and no over heating).

My personal preference is to fill the block before any machine work is done but after the block has been deemed usable since theres no sense in filling a block that your machinist finds a crack in later.

As far as stepping up to to an aftermarket block....by all means do so if the budget allows but then again for V6 guys like myself aftermarket blocks dont really grow on trees and if they did the price would still be wallet busting for most mere mortals. Aftermarket V8 blocks are plentiful but but the cost still isnt just a few pennies more than a stock block and a partialy filled stocker is pretty stout when you look at cost per hp.

My .02 FWIW

[MonzaRacer]

OK my point is you take your stock block in and pay for shgort fill kit installed, as it is time intensive if you have never done it let professionals do it. Then you bore,hone,square and line hone the block to makeit perfect(if your gonna waste time on block fill why not fully machine it and add splayed caps). so by this time you have a block that is still a weak link stocker(not knocking it but for few bucks more you can get an aftermatket block) with lots of cash invested.
I prefer to use an aftermarket block as most of them will just need a finish bore/hone. and thedecks usually dont need anything unless you are going for a specific Deck height. you will have less flex, more stable deck surface and actually make in a full boogie engine (which you seem to be building)that is still a standard bore (which leaves room for more future rebuilds/updates) and will make more power for equal size stocker and hold up better if you get crazy with power adders.
Honestly I have built both small block and big blocks and never ran hard block and unless you intend to run crazy boost/NOS levels and just take it to the Nth degree of trying to trash you wont need it.
My buddy has a drag car and his first 355 had a full tilt set of Indy Cylinder Head port/polished Dart/World Products Sportsman II's (yes first ones out ,very sweet),Oliver rods, wiesco pistons and a custom ground Cam Motion cam and that car NHRA legal and 14.5 to 1 ran that car to a best of 5.70s till a bad crank trigger sensor pulled the #2 main web out and the first 2 throws bouncing off the ground. It was filled to the bottom of the water pump hole, The deck had the big hole plugged, all the big tricks, and after we rebuilt it, New crank, new rods, couple new pistons and no block fill and the engine is still running and the heads got rolled over (angle milled) 0.125 after having been milled .060 before (he wanted more compression) It still runs but never really picked up after the extra milling, and the block still looked great even with no filler.
Hey silver bullet, buy a good stroker kit, internal balanced, an ATI super damper and a good set of AFR heads (yeas I love AFR heads) have either Cam Motion or Comp set you up with a custom cam ground specificly for your application.
Bore a good block, square it ,hone with torque plate, add some ARP fasteners and tada your ready to run. Up to 500 horse you can run stock caps on block if you want to boost it or squeeze it spend money on some splayed caps on a 2 bolt block. Leave the block fill for the turbo/NOS guys adding over 15 psi boost/250 shot and spend your money on good heads and quality fasteners and internals.
Trust this I build 355's making 500 hp as a rule for lots of folks and never use filler and unless its a maxed out track engine a quality build with a flat torque curve will make you smile from ear to ear.
Last engine I shipped out was a 355 roller block with an Eagle rotating assembly , GMPP LT4 HOT roller, 1.65 roller rockers, AFR heads, RPM Air Gap, 930 HP and older Holley ProStrip Anihilator. Made 523 hp on pump gas and fella paired it with a TKO600 in a 78 TA it gets 32 MPG on highway and went 160+ on a straightaway. He says it pulls 1.65 60 fts and runs high 11's spinning offthe line (he is still experimenting with rear suspension tune) He figures it will pull low 11's high 10's on NOS.
I really wasnt sure how good it would run but he loves the engine and wants to build 2 more for other projects he has being built.
I was very impressed with the cam making such good power andd wonder whats gonna happen if we upe the head selection (first one uses 195s ,next one gets 215's and maybe custom cam, same but around .600 lift) The HOT cam makes some awesome numbers with good heads, some say its a slouch on the bottom end but my 355 truck engine has one and stock 1.5 rockers and makes crazy pulling torque.
Remember with a 383 its a torque maker not a NAASCAR RPM engine.
Good luck
Lee Abel

[LowBuckX]

My eyes hurt trying to read that. Half filling the block also helps keeping heat out of your oil. Al'a Vizard. ive not tested it to see.

As long as you do the fill before machine work you will be good.
I cant afford an aftermarket block either.