1991sleeper

iTrader: (-3)

I found these heads locally on Craigslist for 400$ dude said they recently been checked out by machine shop and r good to go ... I'm building a lo3 305 at the moment as was leaning towards the trick flow super 23 175 heads 1200$

The casting # is 14101128 they look like later center bolt heads ? Any info on these ? I read on a forum they are 58cc chambers ? These would work well on a flat top 305 correct ?

Orr89RocZ

iTrader: (20)

128's should be a vette casting, before they started using the 113's

Do believe they are similar with 58 cc chambers and could work on a 305. They dont flow alotbut have some potential with port work

The intake side is similar to 113 i think but exhaust side is not a d port and flows less. Could use work

1991sleeper

iTrader: (-3)

Yea I think I'll stick with the trick flows then .. They flow good out the box and have more potential with porting & 56cc chambers ..... Anyone know what kind of compression ill have with a LO3 block with flat tops (5cc reliefs) and 56cc chamber with .015 gaskets ? Thanks

Fast355

iTrader: (2)

Do not have a calculator in front of me but that should be 10.2 and 10.5. Are those pistons on a 1.54 or 1.56 compression height?

1991sleeper

iTrader: (-3)

1.56 comp height .. Thanks fast! And ur saying 10.2 with 58cc & 10.5 with 56cc? They are also .030 over hyperneutic pistons if tat makes a difference

Fast355

iTrader: (2)

To be completely honest it was a ballpark guess from the hip on unknown measurements.

I pulled up a calculator just now and assuming the piston is stock bore, sits .025" in the hole, has a 4.1" bore .015" compressed headgasket, it is right at 10.1:1 compression. .060" over makes it 10.4:1

1991sleeper

iTrader: (-3)

Yea I think that will be about right where I want it

Damon

Flattops in a 305 with 58cc heads is going to be somewhere around 9.5:1, like the original L69 HO 305s had (they used flattops and 58cc chamber heads). A little more or less depending on your exact deck height, overbore, head gasket and cylinder head chamber volume.

vetteoz

iTrader: (13)

http://forums.corvetteforum.com/1544094715-post2.html
http://forums.corvetteforum.com/1544999715-post5.html
http://forums.corvetteforum.com/1552475280-post7.html

1991sleeper

iTrader: (-3)

I've tried several online calculators and I'm getting between 10.2 & 10.5 on all of em ..
I may get it decked .010 to get me up around 10.7 but idk yet .. I'd like to
Stay on premium pump gas but its Really not that serious not a DD just a toy .. I figure worst case ill run a few gallons of 110 with a tank of premium for
Race nights and back timing off for premium on cruise days

Damon

Well, then you're doing something wrong. Pistons 25 in the hole+ head gasket and 58cc chambers is 9.5:1. You can start shaving it down from there by over-boring, milling down the heads and such but you're not going to come anywhere close to 10.7:1 with flattops in a 305.

Fast355

iTrader: (2)

WRONG!!! I have run multiple calculations and know this is false atleast with a .015" shim style head gasket. I have an engine with flattops and 6cc worth of dished pistons that calculated out at 9.2:1 with 64cc heads. A flattop piston 305 with 6cc valve reliefs, .015" steel shim 350 head gaskets and 58cc chambers is 9.7:1. At .030" over it is 9.85:1. Run 601 heads or mill the 58cc heads down to 52-53cc and you have a 10.5:1 engine.

1991sleeper

iTrader: (-3)

Thanks again fast ! Also I'm doing my figuring with 56cc chambers (trick flow heads) .. I also did it with a 3.840" bore head gasket a couple times.. But Idk if ill be able to use them or not till the heads show up .. I just don't really like the idea of the gasket being 4" with a 3.766 bore ... Seems like there would be a gap or ridge ... Another ? For ya .. What is perfect "squish" .40? Between the piston and the head .. And what is the purpose of decking the block to "0" and using a thicker gasket ?