Thread: Help with Valves on Blown BBC

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I have a 467” BBC with a 871 BDS street blower that I am working on. I pulled it out of the 69 and will be putting it in the 79 Camaro soon. While I had it out I pulled the heads to look inside. I decided that maybe I would change valves to a higher performance valve before putting it back together.
Heads: World Products Grumpy Jenkins Merlin 118cc Iron.
Valves: Look stock 2.19 and 1.88.
Pistons: JE flat top blower pistons.
Cam: Isky custom grind about .600” on a 110 LSA flat solid tappet.
Carburetor: 2 Holley custom 750 double pumper, air horns milled off.
Fuel : Holley Black, Fuel Cell with a Sump mounted in trunk, 93 octance, Aeromotive return regulator -8
Blower: BDS 871 3% Over Driven, hope 10-12 pounds boost.
Rockers Arms: Comp Magnum Roller.
Transmission: Turbo 400 / 3000/3500 converter.
Suspension: Ladder bars with coil overs on 9” with spool and aftermarket axels.
Ignition: MSD Billet and 6AL box.

The question is, should I upgrade the valves to a better valve or will the current valves work for street and maybe a couple of blasts down the strip? Any thoughts on the valves, Manley, Ferrea, other?

Thanks for the help.

You can always upgrade valves in most applications. Just don't run titanium valves.
I have a question that doesn't concern the valves, why TWO 750 carbs?
Just curious as to the rest of your combo you stated.

any good severe duty valves will do .no need for inconels ex less you have alot of money to spend . i used .manleys .competiton valves .howards . ferrea .delwest .pbm .alot of the dart house valves .the last set of grumps i did had 2.250 1.880. i use alot of the pbms as well. alot of the stuff just has there name put on it .manley is good as well as ferrea it is up to you 90% of my stuff is PBM valves. or some ti delwest and inconels manleys

you will run out of road before you run out CFM . i know this well on the street a bit bigger would be good but mine runs great with the 750 afbs with a 548 cid

Originally Posted by nitrowarrior

You can always upgrade valves in most applications. Just don't run titanium valves.
I have a question that doesn't concern the valves, why TWO 750 carbs?
Just curious as to the rest of your combo you stated.

Two 750's or bigger is pretty standard on a 8-71 and BBC. As Pat said it could use a little more but I will not run out of road with this combo.

Okay, Just remember, your low lift and duration selection along with a 110 LSA is not condusive to a blower combo, together with the small cubes, brings questions down the road.

Originally Posted by nitrowarrior

Okay, Just remember, your low lift and duration selection along with a 110 LSA is not condusive to a blower combo, together with the small cubes, brings questions down the road.

I am not sure what you are talking about. The cam was designed by the blower manufacturer and ground by Isky. BDS says "We have found 110° lobe centers to produce the best overall power on gasoline." Not sure how .600" lift would be an issue and I did not post the duration of the cam. Saying that 467" is small cubes does not sound reasonable to me.

Originally Posted by blown69camaro

I am not sure what you are talking about. The cam was designed by the blower manufacturer and ground by Isky. BDS says "We have found 110° lobe centers to produce the best overall power on gasoline." Not sure how .600" lift would be an issue and I did not post the duration of the cam. Saying that 467" is small cubes does not sound reasonable to me.

hey i built blowers engine on 110 they run fine .i have run this cam IN 268 @050 lift 708 EX 272 @050 lift 708 on LC 110 in a 548 with a cr of 10 to 1 with two 750 afbs and the 420 mega blower at about 8 lbs of boost? for over 5 years of hard use she still is running.for boost hard to say were it is . i can not find many that will set in the seat to look at the boost gauge when it go,s in to boost. i have run it up till well allmost there but the car starts stepping out and spining the bf drag tires loose at bout 110+ .so maybe it is all wrong but i sure hate to see if it was all right

I'm not telling you either combo is wrong.
For best combo in an engine that is designed for best all around performance, the "on Paper" and manufacturer's CYA is not in anybody's best interest that's trying to have all their components work together.
Rather than feel that I was putting anybody down, maybe re-evaluate what you have.
If you're happy, great, run it as you built it. I'm posing questions and bringing forward some future questions that will pop up in all blown applications. I just want the set up to be at it's best.
Pat if this poster had your experience, he wouldn't ask questions here for help, rather, he'd be going in a different direction.
Back to what I was getting at, blown69camaro, do you like the sound of the tighter LSA? Did you really research the cam selection for your cubes and street application? CFM, is it for show or how did you come up with that? Run out of road before you run out of CFM or carburation. What? That makes no sense for a cruiser or a street rod or even a drag racer. It has no meaning for your efforts.
It's an off the wall combo and if it works, more power to the project.
Yes, an overbored 454 is not very big and you could use a better cam and re dial in your carb thinking. I still haven't heard what boost you're running or planning to run or how are the carbs setup or dialed in. Nor the reason for the valve question that started all of this.
I just posted some queries and I stepped on toes........hey, I kinda like that too.

i do not know what he looking for.. i know when i built mine there was trade offs the 750 were the biggest carbs they made now they have 800 i like the afbs for street use i did not want 1000 bucks worth of holleys .i shot my load on the blower .we did a egt on the car as close to wot every thing look fine .i had some tell me it would not work .i did talk to mike kuhl he was one of the few that said it would work .it works much better then i every could hope for.good luck