Olds #5 heads

[rocketracer380]

I’m building a 380” olds sb stroker I have ported #5’s with 2.07” in and 1.71 “ ex std port work egr bump filled crossover welded divider gasket match bowl and chamber work and opening the pinch point and casting flash removal std olds port work not max porting should I go with these or just bolt on my stock procomps or Stock milled c heads with large valves I’m shooting for 500+ hp with a 380” 11.1;1 comp with a fairly aggressive solid cam .552” in .568” ex

[mag2555]

You need to get your heads flow tested!

If the Intake side flows 250 cfm@28" at .500" lift without regressing, and the Exh side flows 180 cfm@28" at that same .500" lift then you will make 500 hp.

This assumes your pick of intake manifold can flow that 250 cfm also.

Judging by the picture of the Intake bowl you posted though I must say that your valve to bowl throat percentage looks very small/ stock and a education guess on my part would be that they are going to be hard pressed to flow 230 cfm@28".

The rule of thumb for Even beginning to taking advantage of a given valve size it that the minimum diameter of the bowl needs to be 85% of the valve size.

85 percent of 2.07 is 1.760", then the rest of the port circumference from the throat on back up to the flange needs to be 5.560", and as ported before these are minimums!

[rocketracer380]

Anything over 250 they turn into sprinklers is my understanding they need max porting to flow 260ish being that it’s a short runner I think that 230/240 ish should get me close to my goal with a good comp ratio cam and proper intake I’ve made 450 with a 403 stock no 6’s either only larger valves and a rpm intake this 380” has a more aggressive cam and more compression and mildly ported head I’m running a ported Holley street dominator. I also have a victor I’ve heard that upgrading to a 2” intake over a 1.875 stock nets 220 cfm with no other mods they supposedly flow 190’s stock I understand that that size valves needs I certain csa to work but they should flow more than that.the bb heads flow around 235ish stock I’ll guess I’ll try both and see which feels better seat of the pants don’t think I’ll get to the track this year anyway thanks for the input

[mag2555]

Maybe you should get a flow test of the heads done to nail down the hp potential of the heads and not the go by hp gauge built into the seat of your pants come next year! ?

[mag2555]

By the way, I have found my own Butt gauge to be far more accurate in terms of starting line Torque then HP over the years,lol!