Thread: 72elk

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Please read through this tutorial on the L31 Chevy heads.
http://www.crankshaftcoalition.com/w..._cylinder_head
Write down questions that you have and ask them at the end. These are what I would advise for someone looking for a bolt-on hp increase where you don't want to do a lot of work. Make the seller agree in writing that you can excnange the heads or get your money back if you magnaflux them and find them cracked. Get the stock self-guiding rocker arms with the heads. You will not need the pushrods, they are shorter than conventional Gen I pushrods because the L31 used a roller cam. You can use either self-guiding rockers with no guide plates or you can use conventional rockers with guide plates. You cannot use self-guiding rockers with guide plates. I would use a cam with up to 0.500" lift or just a little more (these heads will stop increasing flow at about 0.500" valve lift) by taking the retainers to a machine shop or a friend who has a surface grinder or Blanchard grinder and having them machine 0.080" off the bottoms of them. This is called a "ghetto grind" and will allow clearance between the bottom of the retainer and the top of the valve guide oil seal at full lift when using a cam with more lift. I would also drill and pin the studs. The article says that it is a stop-gap measure. Baloney. It's a permanent fix for preventing studs from pulling out of the heads. Mr. Gasket makes a kit to do it.
https://www.summitracing.com/parts/mrg-806g

I would not use an Avenger carburetor. Use an Edelbrock 650 AVS or AVS2 on an Edelbrock 7116 manifold. Install 1 5/8" full length headers with an H or X pipe installed immediately after the collectors. Build the motor 9.5:1 static compression ratio with a zero deck and 0.039" to 0.041" head gasket. Use a cam not to exceed 216 degrees duration @0.050" tappet lift with max lift around 0.500". This will make a very streetable 370-390 horsepower, depending on your tuning abilities.

Read through this thread to understand zero decking.....
http://www.hotrodders.com/forum/zero...ck-184870.html
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