~450hp from stock stroke 340?

[273]

Aluminum heads are absorbing compression because they’re a heat sink. If your static is 10.5:1 your cam choice should be in the 9.5-10:1 range.

In theory but in practice I don't believe there's a power difference between the two but yes seems you can squeeze a bit more cr from aluminum heads and run on pump gas probably less chance of hot spots.

The crate motors made power because the came equipped with cast iron heads flowing 25 more cfm than the J head untouched.

I don't know about 25 cfm more, Charles Servedio flowed both and are fairly close to each other on intake side, J had slightly more peak flow and magnum had slightly more low flow, exhaust magnum did a lot better, probably that and more do to port and chamber shape for hp gain.

 

[crackedback]

i have a client with a 67 RS Z28 302/4spd, which i understand is crazy rare. it's a super time capsule and a really cool car. total day two with keystone kustomags, lake wood slappers and hooker's. i don't know if it came with 4.11's or the PO did them along with the other stuff, but it was a serious piece. the guy had me swap in some 3.55's so he could drive it and enjoy it a little more.

but to your point, that thing loves some gear. so much fun to twist its tail and just let it sing.

There was a guy in LA way back that had a 69 Z28. Ran around with 5.38's in it. Launching that car was fun to hear. Screaming little SB.

 

[Newbomb Turk]

Aluminum heads are absorbing compression because they’re a heat sink. If your static is 10.5:1 your cam choice should be in the 9.5-10:1 range. The crate motors made power because the came equipped with cast iron heads flowing 25 more cfm than the J head untouched

Not again.

 

[pittsburghracer]

Not again.

I think every engine builder has his or her thoughts on this subject. I know I have mine and will keep them in the vault

 

[Newbomb Turk]

I think every engine builder has his or her thoughts on this subject. I know I have mine and will keep them in the vault

They can think what they want. But publicly posting error keeps people in the dark.

Aluminum heads don’t suck power. They don’t reduce detonation.

But that myth will keep going because it hasn’t been eradicated yet. Probably never will.

 

[junkyardhero]

There was a guy in LA way back that had a 69 Z28. Ran around with 5.38's in it. Launching that car was fun to hear. Screaming little SB.

might still be down here running around!

a lot of cars from back in the day are resurfacing as the former owners are checking out, have moved on or their kids are now dragging them out to get 'em going again.

i find great joy in putting something back on the street that's been dormant for ages-- even if it's *slightly* de-tuned from what it was back then; they're still cool cars and it's great to see them out running around.

 

[fishmens67]

They don’t reduce detonation

It has more to do with the design of the chamber, not the material

 

[Illahe]

They can think what they want. But publicly posting error keeps people in the dark.

Aluminum heads don’t suck power. They don’t reduce detonation.

But that myth will keep going because it hasn’t been eradicated yet. Probably never will.

They can think what they want. But publicly posting error keeps people in the dark.

Aluminum heads don’t suck power. They don’t reduce detonation.

But that myth will keep going because it hasn’t been eradicated yet. Probably never will.

Newbomb,

Thank you for enlightening me:

My comments were not intended to be misleading, they come from following Larry Shepard's Book. On my budget I follow his recommended cylinder head compression ratio combinations.

Swapping the Speedmaster 2.02 aluminum heads for (New Zealand) EQ 318B 1.92 on my La 360 short block netted me a lower et and better mph with flat top piston combo. The swap included a cam change as well, from the 238/238 108 solid to a 248/256 110 assuming the cylinder pressure went down about 10psi with the EQ's.

 

[Newbomb Turk]

Newbomb,

Thank you for enlightening me:

My comments were not intended to be misleading, they come from following Larry Shepard's Book. On my budget I follow his recommended cylinder head compression ratio combinations.

Swapping the Speedmaster 2.02 aluminum heads for (New Zealand) EQ 318B 1.92 on my La 360 short block netted me a lower et and better mph with flat top piston combo. The swap included a cam change as well, from the 238/238 108 solid to a 248/256 110 assuming the cylinder pressure went down about 10psi with the EQ's.

Interesting.

 

[Mean416]

Newbomb,

Thank you for enlightening me:

My comments were not intended to be misleading, they come from following Larry Shepard's Book. On my budget I follow his recommended cylinder head compression ratio combinations.

Swapping the Speedmaster 2.02 aluminum heads for (New Zealand) EQ 318B 1.92 on my La 360 short block netted me a lower et and better mph with flat top piston combo. The swap included a cam change as well, from the 238/238 108 solid to a 248/256 110 assuming the cylinder pressure went down about 10psi with the EQ's.

You went a lot bigger in cam so definitely the power output got higher. Not sure id attribute the gain to the heads.