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What is the part number on those heads Hafrod? And what symbol is on the ends?
 
I don’t see where the OP specified a certain year Pops. I’ve just always known them as 58cc. All the different numbers You posted is sorta confusing, so it might be that different 265 heads had different chamber volume maybe...?
 
Thanks for pointing that out Dano...Hopefully, Hafrod will get back to us with a year and part number
 
Could be that he’s looking to raise compression on a later motor. I’ve done the same on several BB’s before. The closed chamber heads on open chamber pistons bumps it up by almost a full point.
We'll never know, if he doesn't get back to us; will we? :)

I'm finding that there were two different compression levels for the 265 engine in 1956...There was an 8.0 ratio and a 9.25 ratio: Chevy 265 V8 Engine Specs, Horsepower, Problems : Engine Facts.com Not sure whether this was accomplished with head chamber volume or piston domes.
 
Discussion starter · #12 ·
I have an 87 SS Monte 305 HO assembled short block. I was thinking it would be cool to use the 305 with staggered 265 heads in a 4 door 55 I got my eyes on. It was a good used engine till I used the heads on a 350. Would cost a lot to have the valve guides done for unleaded but would be neat. I used to know where a set of staggered 265 heads were with Corvette staggered valve covers. I would have to make a hell of a trip just to see if they're still there.
 
Hafrod....Just a thought....What do you think about disguising the 305 HO heads to look like 265 heads....I belive they have lager valves, flowed better and the chamber size was 58cc
 
I'm finding that there were two different compression levels for the 265 engine in 1956...There was an 8.0 ratio and a 9.25 ratio: Chevy 265 V8 Engine Specs, Horsepower, Problems : Engine Facts.com Not sure whether this was accomplished with head chamber volume or piston domes.


Pops no 265 ever had dish pistons, nor did any other small journal SBC. Power pack heads had smaller chambers than stock.

How would you ever disguise a 305 head to look like a powerpack. The accessory holes are a dead give away.
 
Pops you arecorrect a 305 HO has 1.84 intakes, while a Powerpack head whatever it came off has 1.72. As far as valve guides go there are NO mods necessary to run unleaded gas. Exhaust seats yes there are hardened seats available,
 
Pops no 265 ever had dish pistons, nor did any other small journal SBC. Power pack heads had smaller chambers than stock.
I don't think you understood me correctly...I said domed; not dished

Domed Pistons
This piston has a dome-shaped top. It reduces the chamber volume and increases Compression Ratio. However, it can create slow-burning, inefficient combustion chambers.
 
I don't think you understood me correctly...I said domed; not dished

Domed Pistons
This piston has a dome-shaped top. It reduces the chamber volume and increases Compression Ratio. However, it can create slow-burning, inefficient combustion chambers.
Sorry Pops my bad, but Powerpack used same cast flat tops as stock . I think the 305 would run fine on a set of 265 PP heads better on 57 PP heads, A fried bought a Jeep with a 350 and it had 58 non PP heads and it ran well.
 
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1,096 Posts
#19 • May 24, 2016 (Edited)

hutchenc said:
------------------------------- There's a fellow on the Corvette Forum that put a Dart SHP 400 SBC in his C1 Corvette and he disguised it to look like a dual four bbl 283. Pretty awesome build...pretty expensive too. ------------------------------------------------------------
A high winding 302 is something that I've always kinda wanted. Maybe a nice big solid flat tappet to go along with it. Easy to lose street manners with high winding small blocks though :(
Click to expand...
There is another guy on CF (me) that built a .030 over SB400 and disguised it to look like a 57 fuel injected 283. The FI unit is one which was modified by Bill Thomas (heavily ported out) and has been upgraded to perform like a 65 FI unit. The heads are 66 2.02 which have been worked over and the double humps on the ends were ground off and pyramid symbols were shaped to resemble 57 539 heads

He disguised 66 462s a whole lot simpler than 305 heads with accessory holes and the raised bosses.
 
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