Hello Guys.

I've built a few stock type 455 Olds motors with success. Now I have a customer with a higher goal in mind. I'm building a 455 with stock intake and manifolds. However horsepower goals are amibitous IMHO using the stock intake and exhaust while maintaining enough vacuum for power brakes. My question would be is it worth going over to a hydraulic roller using factory manifolds and intake? He wants 450 to 500 horses, which would be easy with headers and an aftermarket intake. Another question would be that I assume the factory C heads would need to be machined in the spring pockets for the higher lift, correct? Sorry for so many questions. I'm open to ya'll's expertise here.

Many Thanks
Darren

 

There are lower lift hydraulic roller lobes available out there. Yes you can machine the spring pickets as well to help in using a taller spring.
But the first question You need to ask him is does he want 450 hp or 500? Big difference there as even 450 is ambitious with the stock iron intake and ex manifold in their truly stock condition. But it can be done with careful planning and good parts, ie head work, more modern piston and ring packs etc.

 

Thank you. Yes, having C heads bowl ported, will have the larger valves installed as well. Also trying to pick out a piston that will yield enough compression yet not detonate on pump gas. I agree on everything you say, as I'm trying to be very strategic.

 

You should be able to find valve springs that will handle .600" lift on C heads without cutting the pockets; I'ld think you wouldn't be going with that high a lift anyway with stock manifolds.

 

Check out some of the Dyno posts that I put on this forum. That might give you some good guidelines.Also there are +.100 valves available. From there I’d use eagle rods and the piston I use from Race Tech. Those will help you get the right compression for a street build and get you to your hp goal

 

Thanks cutlassefi!

 

Be very careful cutting spring pockets on C heads. These heads are very porous . Not much material to remove also before hitting water. Just a caution reminder that machine shops do not always know. Marks Cutlassefi has done several builds and his advice should be followed.

 

No problem. I have Dyno sheets on a whole lot more builds as well if you’re interested.

 

Yes sir, I'm interested. I'd like some suggestions on a hydraulic roller cam profile for a stock stroke 455, around 9.5:1 compression. Using a repop 1970 455 aluminum intake, and W30 exhaust manifolds. I need to gather data and information on everything as I am working with Dick Miller in building a Q-Jet for combination. Thanks again for all of the help and valuable information.

 

No problem. Pm me your email and I’ll send you some dyno sheets.
And for what it’s worth, I don’t care who’s doing your Qjet, buy a wideband O2, you’ll be glad you did.

 

Listen to cutlassefi, he knows his stuff. I built a stock-ish 455 and used his cam. I had stock exhaust and intake manifolds, stock F heads, compression come to 9.8 and used Wiseco pistons. Roller cam from cutlassefi, and roller rockers. I had 427 HP and 512 torque. Also had good vacuum for brakes and even had A/C on it. My only boo boo was that my torque converter was just slightly to tight.