As I've indicated, I'm looking at building a 400sbc for the next motor for my car.

The question is, what is the best way to get there?

Two options as I see it.

buy a 400 block. 3.75 stroke, 4.125 bore.

Or aftermarket block, eithr same specs as above, or as a 350 but clearanced for a 4" stroke.

I've been reading that a 4" stroke puts a lot more pressure on the pistons and cylinder walls due to deflection, but I'm not sure how that all really affects the motor.

Just looking for thoughts and opinions here.

Thanks!

 

A 4.125" bore will do better if your using large valves due to the cylinder wall being farther away from the valve allowing it to breath better and the 3.75" stroke will be easer on the cylinder walls and allow for a taller piston which will be stronger and burn less oil due to you not putting the wrist pin up in the oil ring.

 

If your going to use a 4" stroke make a 427 out of a 400.

 

So you'r saying, stick with a 4.125 bore and go with a 3.75 stroke rather than a 4" bore and 4" stroke?

 

I'd use a 3.75 stroke. Better rod angle have a taller piston and don't have to worry nearly as much about cam clearance.

 

4" in a 350 block does work but you may need alot of clearancing and special oil pan spacer/rails to clear the crank. My buddy did one and ran 10's with a small shot. Need to get small base cam and pay attention to rod to cam clearance. Rod selection becomes more critical there. Piston height becomes very short with 4" stroke.

You could also do more popular 3.875 stroke on a 350 and get 395-397". Leaves bit better rod to stroke ratio and more part selection

 

Ok, thanks for all the input everyone. 4" stroke idea is out.

 

If your going to spend the money though than getting an aftermarket block to build a 400 with would be awesome. I want to build a SHP 400 so bad. I almost got one instead of my vortec 350 I have now. Another option most people don't think about is getting a small 144 super charger. There cheep boost and will make a lot of torque even on a stock motor. You will make more power every were not just higher RPM and there is no lag like a turbo and it dose not sacrifice and low RPM torque, it adds to it which would make it way more fun around town and on the freeway when you want to pass some one. I would supercharge over stroking a motor.

 

Well, if I go with an aftermarket 400, then the forged rotating assembly to get it done. That's my $5000 budget right there. Then I need heads, intake, etc. Gets to be around $7000 real fast.

Can't run a small 144 super charger with a serpentine belt set up is about the only draw back I see. Might be tempted to go ATI later on though. That would be fun.

If I did go ATI and kept my current 355, I'd be in the same neighborhood price-wise once I got all the FI stuff together.