h.p.

[BobsBB]

with my "63" 409 motor (348 h.p.), i had it bored over .030, 10/10 grind on the crank, with a cam w/500 lift, 650 holly carb, 10/1 pistons. my question is about how much h.p. did i gain, as i do not know the formula

bob

 

[Fathead Racing]

Give us a little more info. Like what cam, valve size , head work (ported?) solid or hydraulic lifter?

 

[BobsBB]

info

i had ordered a comp cam, 1600-5000 r.p.m. power range 268/280 duration, .515/.520 lift, and110 deg. lobe sep. angle. the valves are 2.09' intake, 1.72 exhaust. yes the heads were ported/polished when done, comp springs (no milling). Stock intake (also ported/polished) .030 over in the block (no line bore). Hydro lifters.
....can't wait too lite it up

 

[Fathead Racing]

Power increase

That cam would be the XE 268 I presume? 1600 to 5800 rpm. You figured lift with a 1.7 rocker. Lift with stock 1.75 rocker would be, .530"/ .535". I would not use the stock rocker arms. I have BB Chevy 1.72 ratio roller tip rockers with that cam with a lift of .525"/ .528" Should be in the neigborhood of 400 HP. Thats a pretty exclusive hood!

 

[BobsBB]

good info

Thanks for the h.p. info , also for the tip with the roller tip rockers!
If you have any other good tricks to share before the final build, (as i just got the block back from the mach. shop), lay them on me

 

[SS425HP]

H. P.

There are 1.75 roller rockers available. Curt Harvey had them, so someone is making them. Can't tell you where, but might as well look for them as to use 1.72. Same cost, more lift. Negligible, I know. But, there is some more.

Fred

 

[dq409]

I`m using 1.75 Scorpions I bought from Show Cars and they work great and the price is right too!! Great way to get that extra little lift. No reason to cheat your self.,,,dq

 

[BobsBB]

that set of scorpions is just the thing to give that ole' BB some sting !, hey with my cash, and all you members experance, im gonna build me one mean 409 !!

 

[jim_ss409]

I got a set of those Scorpions as well. They look so nice you almost hate to put valve covers on them. They say that headers make a big difference on a 409. Show Cars has headers made by Ballenger that fit well and are reasonably priced. Let us know how it goes when you get it running.

 

[Dond409]

I have 1.8 ratio big block roller rockers on my 409. i also have custom made pushrods, so that the roller rockers stay in the center of the valve tip over full lift

 

[Bungy]

I also have the 1.8 ratio Scorpion roller rockers. The price was the same for the 1.7 or 1.75, so I figured why not go with the extra lift.