should I block fill an aluminum block?

[knova70]

I have a brand new aluminum bowtie sbc race block,I'm going to use 11.1 static compression and a 8.71 blower on alcohol that is turned 20 over and made 23lbs of boost on my old sbc stock 400 block that cracked,just wondering if I should block fill it to the water pump holes,even though I dont want to,due to the fact it will decrease the value of the block if I was to sell it,Please somebody give me some good info on this,and my stock 400 block was filled,the aluminum block is much thicker as is the deck,Thanks

[jaykz1000]

nope no fill at all ... that dart iron eagle block i had that u wanted to buy along time ago i asked the same question poeple said heck no dont do that make it weigh a ton walls are plenty thick....i say no but its your block

[edvancedengines]

How would you replace the sleeves if the block was filled?

Ed

[billhendren]

Same way as an un filled block,there dry sleeves so it wouldn't make any difference. There is no need to fill that block,if its an early block you may want to look at installing larger dia main studs.Bill

[knova70]

I was told it would help to strengthen the cylinders so the rings will seal better,so it wont flex the block,also it is a early model bowtie race block it was manufactured in 1992 I believe but it is still brand new,never used,not sure to fill it to the water pump holes?or not

[jaykz1000]

look at it this way... its not gona hurt anything but your pocket book alil for the fill and add some extra weight to that tank.... so if u can deal with both of them i say go for it kinda like having insurance ... personally i wouldnt bother........ know if it was stock gm block id say fill befor u could get the question out ..

[billhendren]

If its an early block the main and head studs will fail long before you would need filler.the early blocks had head studs that were only .900 thread engagement into the deck.the main studs were only 7/16 with short engagement as well and would pull out under high power use.best thing for early blocks is street use,look for a Brodix or Dart if your going to put out some power and they done need to be filled.Bill

[edvancedengines]

Bill,
Thanks for the info. I have never worked with one of those blocks, so I thought they were wet sleeve blocks.

A question that is in line with what you just posted about the head stud thread engagement. I have a Ford Aluminum BB here now that is a little strange. The head studs are supposed to be 10 of one size and 10 a little shorter, with both being a 9/16 course thread in the block.

Problem is that evidently the block was messed up and this thing as studs for three of the holes on one side that are all different lengths. It gets worse. I can for sure tell that one of the holes is more shallow than the others and that head has a Heli-Coil Thread in it, starting just below the deck. One of the holes had a short thread that allowed appx an inch of stud thread engagement of the stud with the remaining threads above that ground off to not interfer with head gasket and head.

So Bottom line, if you know. With an Allan Root Ford Motorsports Aluminum Block for the A Heads with ten bolts on each side, What do you feel should be the minimum thread stud engaagement on the two studs I am talking about? This will have tons of cylinder pressure at 602 cu in and shooting appx 500 shot of nitrous.

Ed

[knova70]

If its an early block the main and head studs will fail long before you would need filler.the early blocks had head studs that were only .900 thread engagement into the deck.the main studs were only 7/16 with short engagement as well and would pull out under high power use.best thing for early blocks is street use,look for a Brodix or Dart if your going to put out some power and they done need to be filled.BillThe block I have was made in 1992 and it is a bowtie race block,I have the specs that came with the block,it says these blocks were tested to around 1000 hp and didnt fail,I took the main studs out today and they go into the block over a inch,and the studs are backcut,as for the head studs I was going to use arp studs,the holes are blind and are not helicoiled,was thinking of putting those in before the building of the motor,I talked to several people about there dart aluminum blocks and they did also helicoil the head stud holes for security,so hope I dont have a problem also the mains are 4 bolt on all 5 caps and are billet, Thanks

[billhendren]

I have two ford small block circle track engines in the shop and measured the thread depth. the ford motorsports block is 2.00 and the Dart is 1.75.I would think in your application I would set the block up in a mill and drill the shallow holes out to get the same engagement as the others.most aluminum blocks are counter bored approximately .250 from the deck so the load is below the sleeve flange.With the power level your after I don't think you would be successful running a shallow bolt engagement and if it didn't work out and the holes were drilled deeper after the bores were finished i think you would have a bore distortion problem from the deeper engagement.Bill

[knova70]

I have two ford small block circle track engines in the shop and measured the thread depth. the ford motorsports block is 2.00 and the Dart is 1.75.I would think in your application I would set the block up in a mill and drill the shallow holes out to get the same engagement as the others.most aluminum blocks are counter bored approximately .250 from the deck so the load is below the sleeve flange.With the power level your after I don't think you would be successful running a shallow bolt engagement and if it didn't work out and the holes were drilled deeper after the bores were finished i think you would have a bore distortion problem from the deeper engagement.Billnot sure ont he depth of the deck holes,but if I remember right the threads were almost to the deck surface,but not sure,i dont have the block here with me,it started as a dry sump block that I found the right billet rear main cap to make it a wet sump,I have talked to GM racing and swart machine and the block can be converted to a wet sump block by drilling the approiate holes in a bridge port,I bought this block and now I gotta use it so I hope it holds up,I work at a performance and fabrication shop,and we have our own engine builer there and he keeps telling me I need to fill the block,but I really dont think it needs it,after looking it over it is a quite thick block,this is one of the best blocks GM makes as I was told by GM racing R&D department.

[edvancedengines]

Use External Belt Driven Oil Pump. Bam! it is converted to wet sump when you run the lines.

Ed

[billhendren]

Dart and Brodix blocks have 1.500 thread engagement and need no helicoils.early G.M. blocks have .990 and in a high power application heli coils would help.Bill