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I dont know about the small block head,but jon is working on a new big block head. He is currently testing a revised but stock replacement BOSS 429 head. This post on 460.com gives some dyno numbers.
QUOTE,
I have been doing lots of testing with the Boss headed 521". Mostly cam & manifold work. It usually makes 890-905HP @ 7000. This weekend we built up a 429" short block. (I was balancing the crank and honing the block yesterday morning) The chambers were bigger than I remembered, 90cc. So the 521 was really at 10.4 compression, not 10.9. The 429 needed a .080" flat dome to get 10.4.
This engine has a stock 429 cast crank, .010-.010, stock 2-bolt block, a Comp 252-252@ .050 solid roller cam, and our prototype Boss Hemi heads and intake. We used Eagle 6.605 rods and Diamond pistons with 1/16, 1/16, and 3/16 rings.
I have never dyno tested a 429 sized engine. I figured with the 3.59" stroke it would be pretty lame down low.
6000 710
6200 725
6400 740
6600 760
6800 770
7000 780
7200 778
I don't have the dyno sheets here at home, so this is what I remember.
Peak torque was around 630 Ft/Lbs. It would take a load at 2400 with no problem. I don't think it was ever under 500 Ft/Lbs. Imagine how good it would be with 20 degrees more cam and 2 points of compression.
This is a really fun project to work on. I like the fact that it will make great power with very little camshaft. It has plenty of bottom end, no matter what size stroke is in it. All the testing done to this
point has been with streetable compression. (10.4 Max)
Next week I will be testing different valve sizes. Right now we are at 2.300 and 1.900. ..... Jon Kaase
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