I have a 454 at the machine shop. It had spun a bearing and had an oil pan full of bearing flakes. They turned the crank and could use it, did a valve job and are ordering rods and pistons. If I wanted to bump up the compression from the sad stock numbers of 8.5 or 9 into the 10 range what is the best way? Can I have the block decked or the heads milled or is it better to get different pistons to achieve this? Also what is a good cam for serious low end grunt.

 

Well what heads are they, more importantly what are the casting numbers.

I would altleast zero deck the block, to it up the compression alittle and improve the quench.

 

I don't have head casting numbers but the engine is either out of a 1 ton gmc dually or a 3/4 ton Suburban both are about 1986. Does that help at all?

 

Not really. Like SBC heads, there's a page of casting numbers with more combustion size choices than SBC ever had. There's a chance they're 781 casting or some other casting for 119cc open chamber heads but that's only a guess. I'm not sure if they still used that casting in the mid 80's. It's more possible they have the peanut port smog heads that have no potential for performance. The 781 casting is one of the better oval port castings. Some 2.19/1.88 valves and a bit of port work and these heads work fine.

Since you're going to be ordering pistons anyway, get pistons that will work with 119cc open chamber heads to the compression ratio you want.

You're ordering rods also. Before you buy the rods, see of you can get the piston you want that will work with a rod length of 6.385". If so then buy the 1/4" longer rods (6.135" is stock) to go with those pistons. That combination will give a better rod/stroke ratio

Buy any of the Comp Cams Xtreme Energy cams that will work in the rpm range or style of driving you intend to do.

Getting the block decked takes a lot of time. They can do a quick cut to make sure the deck is square but to determine how much to cut off for a zero deck means having to do a partial assembly to see how far down the pistons are in the cylinders. Assemble, tear down for machine work, assemble, probably tear down again for more machine work. It depends how much has to be done to the block.

Don't be afraid to use a dome piston to bump up compression. The head design is different than a SBC and a dome piston is very common in a BBC. I just bought new pistons with the biggest dome I could get. Compression ratio with my heads will be about 14.2:1 but I'm running alcohol so it's still not high enough. 15-16 would be better but that would mean having to use a smaller combustion chamber head or having machine work done to decrease the size of the combustion chamber.

 

Thanks for the reply. I guess I am looking at a "mildly modified" engine, still good overall general use engine but since it is apart I figured I might as well do a few simple things to beef it up. There is a shop in town that has a good rep for working with heads and a cam is an easy upgrade, I think I'll try those two things first.