Thread: 402 big block build

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Agree with Jerry, sell the 402 to someone you don't like and buy into a 454. But you may be one of those hard-headed guys who has to do it his way and see how it turns out. In that vein, here's how to build a 427/434/440 out of a 396/402.

396/402 block, bored to 4.125" to build a 427 or 4.155" (+0.030" KB pistons) to build a 434 or 4.185" (+0.060" KB pistons) to build a 440.
454 crank
396/402 rods
Keith Black KB361 hypereutectic pistons/rings
https://www.uempistons.com/index.php...oducts_id=3069
Here's the best price I've seen on these pistons....
http://www.cnc-motorsports.com/pisto...-125-bore.html

11.1:1 SCR with 96.5cc chambers
10.2:1 SCR with 105cc chambers
9.0:1 SCR with 119cc chambers

If this rig has to run on pump gas, I'd be using heads with chamber volumes somewhere between 112-118. 112cc chambers would make ~9.60:1 and that's where I'd build it. We're talking iron heads here, so that's gonna be about the limit for pump gas and iron heads. You may be able to skate by with a little more SCR today, but none of us have any idea what the fuel quality will be tomorrow. I remember sitting in line for fuel during the Arab Oil Embargo and the only thing you could buy was cat piss regular unleaded. Don't ever think it couldn't happen again, so build on the safe side. A decent set of oval port heads would help some, I would think. Something like 049 heads milled to 112cc's.

Running this solid flat tappet cam installed straight up with the 9.60:1 Static Compression Ratio would produce a Dynamic Compression Ratio of 8.245:1 on the KB calculator, just right for a street motor on pump gas. Will it make 500/500? Probably not, but it should be a lot of fun on the street from 2000 to 6000 rpm's. Use lifters that have the 0.012" oiling hole EDM'd into the crown. Big block Chevies are tough on flat tappet cams.
http://www.lunatipower.com/CamSpecCa...rtNumber=08203

Pat McCarthy and Jerry Clayton are the resident BBC experts and I doubt they would put their blessing on this build, but like I said above, if you're hard-headed like some of us, you'll have to try it.

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