connecting rod numbers

Brian, please post on here what grind numbers Cam Research recommends. You are using GT40P heads right? Are you having the block decked any? If using a .038 to .040" head gasket you'll want your pistons to be "in the hole" @ .005". That will give you an almost perfect quench distance of .045".

probably keeps them really busy, Tr that was for you

Great information, thanks!

Brian A,

I haven't gotten that far yet, any suggestions? The machine shop said to put the old one back in, it looks fine. If I'm going to all this trouble, I think I want something a little hotter than the stock cam.

Brian A,

I took those pistons to the machinist this morning. He thought the one piston should clean up alright. Thanks for your help!

Quigs85SN2001 wrote: Brian, I finally got word from the machinist this morning that .030 over will work. I'd like to buy your pistons, if they're still available. Let me know how you would like to proceed. My home email is margaret48350@comcast.net

Brian, I sent you an e-mail to your comcast address. I still have the pistons.

Brian

my machine shop person/tech/mechanic/machinist/guru told me .030 was the min that a 351 would be bored. That sound right?

just got the news from the machine shop, one cracked head and will need to go 30 over. He's done several marine apps and says he can get the main seals. Ordered them today from skidim but the rear main is on backorder but they seemed pretty sure it would be to them in a couple of days.

no problem I didn't think you did really, just making sure, thanks!

Interesting term "quench" I guess it's similar to "squish" in say a Sea Doo two stroke. it's ususally measured by putting a piece of solder in through the spark plug hole and bringing the piston up and squishing the solder and then micing it. Putting on a different thinkness cylinder base gasket changes the height the piston reaches.

I found this site very interesting on gt40p heads

http://www.stangpro.com/html/articles/gt40p_files/gt40p1.htm

These pistons have a D-shaped recessed area and are sometimes called "quench type" pistons. They work great with GT40P heads. If you don't buy mine I recommend you buy some that are similar. After your machinist bores and hones the block to the piston, have him do a mock-up assembly of the crank, 1 rod (bearing included) and 1 piston. Then measure the deck height (The distance from the blocks deck to the top of the piston). Not sure on Fords but most Chevys have at least .025 deck height above the piston. The idea here is to get your deck height and your head gasket thickness to total up to .040" to .045". Milling the blocks deck may be required if you can't obtain the right gasket. Some say .040" doesn't leave margin for error so shooting for .045 will give a little breathing room. More than .050 some say is not an effective quench height. Silvolite's website talks about this in detail so read up on it more before you decide. SBFs and SBCs are both "quech type" engines due to the way that the combustion chamber is shaped and both engines can take advantage of this added detail. But many builders don't take the time to set them up this way unless you request it. Anyway, read Silvolites website article on quench.

The advantage to setting the quench height is that your engine will be able to handle the added compression of the GT40P heads without having to run premium fuel. So why doesn't the factory set new engines up this way? They used to back in the 1960's and early 70's until the EPA came down on the industry for tail pipe emissions. Quench is not good for HC emissions.   

Hi Brian,

My guy won't bore until he gets the new pistons. It is amazing to me how hard it was to find a good machinist in the Metro Detroit area! I am installing GT40P heads, and would appreciate any hints you might have.

Thanks Nutty! I haven't heard from the machinist regarding the bore size yet. If your .030 will fit the holes, I'll take them. If not, . I'll let you know as soon as I hear from him.

and have him have 150 more hp than ME? I guess I just look this way:)

hummm, very interesting, That will be something I'd do with mine, this is just for a friend of a friend and it's going back stock. Now for my motor, that would be a great winter project. Was out yesterday and the weather was perfect!