390 FE to 427 FE stroker

[Dominik]

Good morning,
I found plenty of articles on the web, plus bits and pieces here, but not 100% what I am looking for.

South Africa is a place for good engineering, but bad for importing from the USA.

I like to build a stroker 390 to get to 427. I read that I need 4.125" stroke, 30 over and Chevy BB rods. I have a 390 crank.

Are the BB rods the same width as the 390 rods?

What is the pin/compression height of the piston, assuming Zero deck height?
Knowing the latter may allow me to find flat top pistons for 11:1 CR locally.

Can bigger valves fit the original cast heads? I don't have them yet, so I can't provide casting numbers.

What is a good hydraulic lifter cam, so that I can keep the stock rocker arm assy.

I am not after top hp and torque.

[undy]

You really need a matched rotating assembly, crank, rods and pistons. The BB Chevy rods won't work on your stock 390 crank. Even if they would you have insufficient stroke to reach 427 ci. Your cast iron heads will accept a bit larger valves but the improvement will be minimal, maybe not worth the $$. I would go to a hydraulic roller, not a hydraulic flat tappet. That will yield more HP and eliminate the lifters takin out the cam problem. Remember, with any cam change you'll need to revisit if the valve springs need to be changed. Don't cheap-seat the rebuild. It'll come back to haunt you.

[Grubby]

I would contact one of the reliable engine builders and have them help spec parts.

Brent Lykins is a regular on this board and can spec and supply all you need.

John

[Dominik]

Morning,
in the two days I couldn't log in, I got the same valuable input from blykins: The 390 crank does not have enough meat to grind to 2.20" and give 4.125" stroke.

What was I thinking? Had this be possible, there wouldn't be any 390 cranks left since the early 70s!

[patrickt]

Originally Posted by Dominik

Morning,
in the two days I couldn't log in, I got the same valuable input from blykins: The 390 crank does not have enough meat to grind to 2.20" and give 4.125" stroke.

What was I thinking? Had this be possible, there wouldn't be any 390 cranks left since the early 70s!

Dominik, FWIW I have a 4.125" stroke and a bore of 4.155” (bored .025” over from stock). But I started with a 428 block. If you've had your block tested, you might just send blykins the results so he can see how much "meat" you have on the bone. He will then be able to tell you just how far you can safely go. There are plenty of stroked "smaller" FEs here in the states and a number is just a number, so I wouldn't be hung up on shooting for 427 cubes. It doesn't mean anything. You can get a lot of power out of any FE that doesn't have a window in the side of the block.

[blykins]

Yep, I wouldn't be concentrated on the "427" because it will never be a true 427. It's just a stroked 390.

A 390 with TFS heads can make 540 hp on pump gas.