Hey all, I've been in the process of preparing to build up a 350 block that I have sitting in my garage. Orignally I was just going to bore it over, get a stroker kit online and build a 383 but someone suggested to me last week that I bore it .040 over and make it a 389. Can anyone tell me if there are any problems with going .040 over with the 3.75" (400 small block) crank shaft? I'd like to see 500 horses out of this motor. It's going to get some big heads and a moderate/wild cam with a high flow carb. I already have the headers, 3" exhaust, high flow cat, subframe connectors, and wonderbar. I am in the middle of a transmission upgrade now, and I will have a ford 9" before summer... I need to know more about the 389... has anyone done it? Can anyone tell me more about it? Help!

IMO dont do it until you have to. Unless you need the cylinders bored to meet tolerances dont waste your time. Youre just making the cylinder wall thickness less while making your block more weak. Especially if you are putting a monster stroke on it. The cylinder walls will not desipate heat as well causing the block to overheat. If it doesnt overheat it will just be more stress from the heat on the block. Plus when you have 50,000 miles in your block and you need to have it remachined. (Yes you will have beaten that thing to death by 50,000 im sure) Then you dont have anymore material to bore out. Then you will have to get a new block or have the block sleeved. just my Anybody else disagree?

Agreed. Machining of the block is doen for maintenance, not performance. Those extra few cubes wont matter much. .040 and a 3.75 stroke should make a 385, not a 389. If you are wanting to make a stroker motor, dont waste your money on a 400 crank. Buy an aftermarket. By the time you pay all of the machine work on a stock crank, you could have bought a nice cast steel one for cheaper. Dont shoot yourself in the foot.

I didn't mean it to sound as if I was going to use a stock 400 sbc crank, everything that I am buying is going to be aftermarket and forged.

But if I am going to buy all new aftermarket parts anyway... and the prices are the same... is it worth my wild to get a couple of extra cubes out of the block in the process?

No. It's like 3 extra cubes. Won't make a difference in power whatsoever and as already mentioned, you just won't be able to machine it again later. Only bore it as far as it needs it.

My 388 is a 350 bored .060 with stock cast 400 crank, stock X beam rods,....its in the sig.Never dynoed it so I have no idea what it's actually pushing for HP, just know it takes quite a bit to move 3600lbs down the track for 10.9? passes/consistent 11.00's That's right up there with the stripped down race only cars that make up the majority of my class.

I cannot build heat, but that's just a matterof changing water restrictor under the thermostat housing. I drive mine on the street whenever possible, but it's not a dail driver. If it was a daily all I'd do is swap out the solid roller for hyd. roller and install OD tranny. This combination gets beat to death all spring/summer/fall every weekend at the track and beat to death on the street when I take it out. 35-3800rpm down the interstate when I drive it to the track for non point race fun events.

Dont be afraid