So I am on this site alot but i have never posted anything. I thoguht i would come and tell everyone some happy news. I have just bought a brand new ls3 block, and had it bored and stroked to a 427. It has Eagle forged rods and crank, and Mahale pistons. I should be getting the motor back from the machine shop next week. A custom cam is in the works. Its a 238/240dur 605/608lift from comp cams. Et Performance 225's and the fast 92 with 90mm TB are to come and then ill be putting it all in a 2000 c5. i already have the rpm stage 5 six speed and the LS7 clutch. Well just letting everyone know what the plans were.

 

Sounds pretty good, although hopefully you didn't have it bored much (there really isn't any cylinder thickness there than isn't needed for strength and heat conductivity, particularly if you are going to go high revs or mild boost, one of which will be required to get your 650 HP. It will pay to get roller lifters and rocker arms along with really good springs and retainers.

I had a very similar engine in my '02 ZO6, it was a C5R block, made for 427 but otherwise the same as you are building, with really good heads, top end Crowler lightweight rotating assembly, a 238/240 cam with .612 lift, CRowler roller lifters and etc., FAST big port, 90 mm, etc., all put together by Charlie Hempfield (pro Nascar engine builder). With 1 7/8 headers and a GHL catback it made 515 RWP NA (driveline losses in a M6 C5 are about 11.5%, so that is equivalent to about 582 HP flywheel). However, the engine ran only 10.2:1 compression ratio (deliberately lower than the 11.5:1 I could have run, so I would have room to take some boost, but an increase to 11.75:1 would have brought it up to about 616105-620 flywheel not sure where you will get the other 30-40 HP. MIght think of leaving compression lower so you can add some boost later.

 

God bless people with so much extra money! PG.