Thread: need advice building sbc 350

Tweet

Typical topic, but kinda looking for some direct advice, Looking to build a chevy 350 on a budget, not looking to do lower end work, just wanna know what will fit best an work well together, and get as close to 400hp as possible. I found a complete running vortec motor on Craigslist, and i just want to know what cam will best fit the heads, and what vortec intake to buy, and what carb will work the beat for what I want out of the motor. Thanks in advance for your knowledge

You'll need to give tire size, rear ratio, transmission type, car weight before these guys can pick your cam.

Not the best idea to bump a motor to 400 go without bottom end work.

It's going in a stock first gen mazda rx7 with a turbo 350, car weighs under 3000 lbs don't know rear end or tire size

Vortec means a lot of different things to different people, so it's best to know exactly what you are beginning with. There is a block casting number on the driver's side of the block at the back, just before the bellhousing. There is also a suffix code stamped into the block deck on the passenger side, just in front of where the cylinder head ends. Post these numbers so we can offer the correct information to you.

If this is an L31 motor, the heads are the best that Chevy ever cast for a production motor, but they still will not support 400 hp on a 350. You might stretch 'em that far on a 383 though. The main problem is that they're cast iron. Motors using cast iron heads and pump gas should be limited to 9.5:1 static compression ratio and that's another reason the heads will not support 400 hp. I'm pretty sure the factory-stock L31 350 motor was rated at 9.4:1 SCR, so it'll take a cam something like 205 to 210 degrees intake duration @0.050" tappet lift without much complaint.....

Some fellows, when they are new to rodding, think that the motor will take any cam you shove into it and go happily making horsepower. Not true. The static compression ratio, fuel used and camshaft intake valve closing point decides what cam the motor will tolerate. You can get an idea of this by reading this tutorial that I wrote for the crankshaft coalition wiki.....
http://www.crankshaftcoalition.com/w..._compatibility

.