454 Chevy - four bolt blocks

Larry Woodfin · Post by **Larry Woodfin** » Thu Feb 21, 2008 10:21 pm

Racers,

I need a couple of 454 Chevy, four bolt blocks. Let Me know what y'all have.

Thanks
Larry Woodfin

Speedbump · Post by **Speedbump** » Fri Feb 22, 2008 8:03 am

I'm sure most of you know but, all of the older 454 blocks with the 7.140 cap register are the same, 2 or 4 bolt. The 2 bolt blocks even have the casting lump where the outer bolt holes should be drilled. I have been converting these blocks for a while now. It might seem kinda back yard but you can locate the 4 bolt cap using the stock 2 inner bolts since both caps use the same register length, then use a locating punch to mark the outer hole positions. I use a mill to center on the punch mark, counter bore and drill/ tap, but a creative guy could make a drill bushing/fixture to ensure the hole was drilled at 90 degrees.(I forgot that damn deyboard shortcut I just read about) Usually looks as good or better than factory. The only caveat is make sure you dont drill too deep, 1 inch or slightly less, or you will hit the oil passage which can ruin your whole day.

Tod74 · Post by **Tod74** » Fri Feb 22, 2008 8:52 am

I have a question about an old block I have. I hung onto it but was afraid to use it without talking to someone that knows.It is a 512 casting 4 bolt main block but the main caps have been "pinged" for lack of a better term. What I mean is it looks like someone took a chisle and put small indents in the block at the edge of the step where the main caps sit I guess to tighten them up or something.I was afraid to use it for anything other than street car stuff...but can it be fixed correctly? Maybe main studs and align hone? Or is it crap? just curious. I've had it for a long time was thinking of maybe using it to build a spare motor if it is fixable.

Speedbump · Post by **Speedbump** » Fri Feb 22, 2008 9:05 am

That was a real common practice for guys who converted 2 bolt to 4 bolt blocks, especially when using factory caps. If you don't have quite a few to choose from, the tolerance on the registers can let a cap be loose and guys would tighten them up using a center punch or a dull chisel to move the register metal a little ant tighten up the cap before it was align bored. I've read different opinions on whether the register fit is very important other than location. I'm no x spert but I wouldn't be afraid of that block. I doubt if the align bore was affected if it was good to start with. Most aftermarket caps have a few thou extra in width. You could get some, dress the register back up, fit the caps, have it align bored and you would have as killer a stock block as there is.

Tod74 · Post by **Tod74** » Fri Feb 22, 2008 1:21 pm

Another thing that is odd. I have two 512 casting blocks, the one I mentioned and another that is a 2 bolt. The 2 bolt is a 1970 casting came from a Monte Carlo...not sure about the date of the 4 bolt one. The 4 bolt block looks different in the lifter valley. Where the distributer goes in the casting extends up toward the intake around the distributer, but on the 2 bolt block it is different...just a hole. Strange to me since they have the same casting numbers on the block.