Engine Build

[JW76]

Sorry for such a long complicated question but you answered my last post so well.

I am looking to build a motor out of spare parts. This is what I am thinking of using: I have a 350 block bored 30 over, speed pro pistons flat tops with 4 valve reliefs, standard factory rods and crank. I have a weiand stealth intake (dual plane) a holley 650 double pumper carb. The cam I have is 470 470 lift 224 224 duration w/ LSA 114 degrees. The heads I am thinking of using are World S/Rs with 1.94 1.50 valves and 76 cc combustion chambers .550 lift springs and 1.5 roller rockers. The compression ratio I came up with is 8.75 - 9ish. I am going to run this with a 1800 stall or 2500 stall converter, turbo 400 with manual valve body, and a 276 rear gear ratio. Will this combination work well? Any idea what horse and torque I might push? Lastly, is the CR too low?

Thanks for your help

[68c10owner]

your compression is a alittle low but not too bad. Your biggest problem is your 2.76 gears. You would have better performance with 3.73`s.

[JW76]

I am going to switch to a 3.73 posi rear afterwards, but for the next year or two the 2.76 will have to due. Is there anyway to hike the compression just a little bit. I had read about shaving the bottom of the head a little bit or using a thinner head gasket but don't know much about this. When I figured the CR I used a .041 gasket.

[68c10owner]

Well you can shave the head and use a thinner head gasket to help compression. you need to know the deck height though so you can set the quench. A standard deck height is .025" and GM used a .015" gasket to give a .040 quench. If you`ve never decked your block then your looking at roughly a .025" deck with a .041 gasket for a .066" quench. Too much quench can actually promot detonation. Another thing to consider is the bore of the head gasket. You have a 4.030 bore so there is no need for a 4.155-4.190 bore gasket. I would just use the steel shim gaskets which should get you close to 9:1. you can shave the head but if I remember right you can only flat mill the World heads to 72cc`s but then you`ll be maxed out. I would go with the 2500 stall as well.

[JW76]

Thanks for your quick response and your help. Could you explain to me exactly what quench is and what it does?

[68c10owner]

Read this. it explains it.

http://kb-silvolite.com/article.php?action=read&A_id=35

Read the 4 paragraph closley regarding too much quench

[JW76]

That could have a lot to do with why my current engine detonates. The person who helped me build it told me to use a thick gasket to drop the CR. So, the .041 gasket and the standard deck height combined is a bit over the optimum .04. Thanks for the link.

[68c10owner]

Well it could be more than the quench causing the detonation. It could be your ignition timing, too much static compression, whatever. I don`t know what you got now so I can`t help you there.