[Stan Weiss]

Originally Posted by SD455DJ

The most recent 455HO that Dan built and Dyno'd is the one for my GT-37. It too is .040 over, 8.6 to 1 compression, Summit 2802 (224/234/114 @ .466"/.488"), untouched stock heads and factory RA manifolds made 430 hp @ 5000 rpm and 535 lbft. torque @ 3500 rpm. So, fairly similar numbers, but this 455HO isn't a max build for the Pure Stocks either. With this cam, it still pulled 20" vacuum at 1200 rpm and 18" at idle...very minimal lope if any...sounded very stock.

Dennis

Stan

[Formulajones]

Originally Posted by Stan Weiss

Stan

That's a nice stock type engine Stan that makes plenty of grunt.

I kept my bird pure to the PS rules with it's RAIII 400 but it's not a max build either. It had to run on pump fuel so I didn't maximize compression like most of those guys do. It made 301/355 on a chassis dyno through a 400 turbo, stock converter, and 12 bolt rear. It's run a best of 12.89 at 106 with a 3890 race weight and 3.31 gear. Stock 70-up style RA manifolds which reportedly aren't as good as the long branch stuff. If I had to guess (haven't had it on an engine dyno) it's probably making around 370-ish HP and 450-460 tq.

I did build a more performance oriented 72 455HO a couple years ago, with round port 7F6 heads, a custom 239 @ .050 hydraulic roller and 10:1 compression that made 507hp 571tq on pump gas through the same stock as cast RA manifolds.

So these manifolds do have the ability to make some decent power right out of the box.