I just bought a set of sportsman II heads, since the stud was pulling out of my camel humps. The engine is a 350 either bored .030 or .060 i cant remember which one. I want to achieve around 11:1 compression. My question is do you use the gasket bore exactly the same as the engine bore? and also do stock size pushrods work or do i need longer ones with these heads?
__________________ 2000 ss m6,cme,lid,wait4metune,ported tb, ls6 heads+intake, mac mids w/ory
I just bought a set of sportsman II heads, since the stud was pulling out of my camel humps. The engine is a 350 either bored .030 or .060 i cant remember which one. I want to achieve around 11:1 compression. My question is do you use the gasket bore exactly the same as the engine bore? and also do stock size pushrods work or do i need longer ones with these heads?
Gonna need some more info to get you on the right track to 11:1 compression. Most notably, what piston are you running, flat top, dome, dish? Also, do you know the volume (cc) of the valve reliefs, dome or dish? As far as gasket bore, no, it won't be the same as the block. It'll be a bit larger. I think the Fel Pro's are 4.166". Stock push rods may work, but there are other factors besides the heads that come into play there. You really need to measure for proper length. You can get pushrod length checking tools from any of your favorite speed shops. They're not a big ticket item, $20 or so.
__________________ 2001 Z-28....Gone, but not forgotten!
The gasket will work, but you are looking at about 10 to 1 or so compression, maybe 10.3. Which is fine if you are going to use 93 octane. Any more than 10.5 to 1 and you will have detonation usually with iron heads.
The weight argument it stupid, compare a Warhawk LS motor to a all aluminum BBC, the weight difference is worth it to me with the kazillion more cubes.
With that combo, I'm thinking you're under 10:1. Probably more in the 9.6:1 range. To get 11:1 you'll need chambers in the 55cc range with a thin gasket. Not going to happen and as stated before, unless you're running race gas you're going to run into detonation problems with cast iron heads.
__________________ 2001 Z-28....Gone, but not forgotten!
I'm using a virtual engine calculator, but I keep getting I different number form you guys can you tell me if i made a mistake somewhere? I entered 4.060 for the bore size 3.48 for the stroke and for the head volume i took the 64cc and added 6cc for the valve reliefs on the pistons and 4cc for the gasket. Then for the gasket bore I used a 4.1 inch and the last criteria was gasket+deck in inches. I wasnt sure about that one so i entered the gasket thickness of 0.018 and I keep coming up with 10.47comp, can you tell me if I messed up somewhere?
__________________ 2000 ss m6,cme,lid,wait4metune,ported tb, ls6 heads+intake, mac mids w/ory
I'm using a virtual engine calculator, but I keep getting I different number form you guys can you tell me if i made a mistake somewhere? I entered 4.060 for the bore size 3.48 for the stroke and for the head volume i took the 64cc and added 6cc for the valve reliefs on the pistons and 4cc for the gasket. Then for the gasket bore I used a 4.1 inch and the last criteria was gasket+deck in inches. I wasnt sure about that one so i entered the gasket thickness of 0.018 and I keep coming up with 10.47comp, can you tell me if I messed up somewhere?
Everything looks good with 2 exceptions. The valve reliefs are most likely a little bit bigger, maybe 7-8cc's. The big number you left out is how far down the pistons are in the bore. Unless the block has been decked, they are probably .020"-.025" down in the hole and most standard head gaskets are around .040". That'll give you .060"-.065" for the entry you were not sure about. Punch those numbers in and you should come up with somewhere around 9.6 or 9.7:1.
__________________ 2001 Z-28....Gone, but not forgotten!
thanks for the help I punched those numbers in using the -8cc for the valve clearance and 0.025 for the deck height. Im gonna get 4.1bore x 0.015 thickness gaskets and that gave me a 10.1:1-10.2:1 comp which should be good for pump gas
__________________ 2000 ss m6,cme,lid,wait4metune,ported tb, ls6 heads+intake, mac mids w/ory
thanks for the help I punched those numbers in using the -8cc for the valve clearance and 0.025 for the deck height. Im gonna get 4.1bore x 0.015 thickness gaskets and that gave me a 10.1:1-10.2:1 comp which should be good for pump gas
That sounds about right with a .015" gasket. That's a little on the high side with iron heads, so watch your tune up and you'll be fine.
Quote:
Originally Posted by 7.0 camaro
ive used those 1094 gaskets for years. never had a problem. they say you gain more power through more quench than the compression ration increase
The optimized quench is a big plus, especially in the area of detonation resistance, which will only help in this case.
Please double check the deck height while the engine's all broken down just to be safe. Without knowing the compression height of the pistons or weather or not the deck has been cut you can't be sure of the deck height. The .020"-.025" I used before is a general number and to assume here could cause severe engine damage. You really don't want to go any tighter than about .035" with the quench (deck height+gasket thickness=quench).
__________________ 2001 Z-28....Gone, but not forgotten!
That sounds about right with a .015" gasket. That's a little on the high side with iron heads, so watch your tune up and you'll be fine.
The optimized quench is a big plus, especially in the area of detonation resistance, which will only help in this case.
Please double check the deck height while the engine's all broken down just to be safe. Without knowing the compression height of the pistons or weather or not the deck has been cut you can't be sure of the deck height. The .020"-.025" I used before is a general number and to assume here could cause severe engine damage. You really don't want to go any tighter than about .035" with the quench (deck height+gasket thickness=quench).
Thats a good idea, the engine builder just gave me an invoice so I dont have any specs on it. Ill call them up tomorrow and ask what their normal deck height is and how many cc's the pistons are, so i dont blow up my engine
__________________ 2000 ss m6,cme,lid,wait4metune,ported tb, ls6 heads+intake, mac mids w/ory
Small block help 
