CK5
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'90 K5 'Barney'
- Thread starter Scribbles
- Start date
beags86
Eastbound and Down
Well there's alot going on. Since you don't have the heads you can't CC them. Punch in some 58cc heads in there and see what you get...
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I agree with Beags. If you don't have heads yet, spec the heads out to get the desired CR out of the pistons you have. If 64 or 58cc chamber volumes don't get what you want, then it may be time to swap pistons. Run the numbers on the 58cc chambers and report back.
beags86
Eastbound and Down
Much better. Now do they make the heads you want in 58?
beags86
Eastbound and Down
Typically the cylinder design is limited in 58s and not the best for high performance use. I think you probably should check your deck height to see how far down in the hole the Pistons are in at tdc.No. From what I see options are stupid limited.
Then play with your calculator, but it's looking like a piston change is needed.
beags86
Eastbound and Down
I would look at the HP/TQ graphs and figure out what heads you want. Runner size/ then plan pistons to match as you go along, before you buy anything.
beags86
Eastbound and Down
More chance to blow them out.
Imo, I would use nothing less a MLS head gaskets these days.
That deck height is killing you.
So have it decked or look into pistons? I’m going to get a friend to come look this over with me and make sure I’m doing this right since it sounds like we’re splitting hairs.
Hopefully I’m screwing this up!
Hopefully I’m screwing this up!
Ideally you’d want around 40 thou quench. Basically, piston would have “zero” deck height plus your 40 thousandths head gasket.
beags86
Eastbound and Down
Stay away from extra machine work if possible. You might need to deck it down the Road or something, this gives you the extra material. Plus once you start decking stuff you can run into fitment problems.
beags86
Eastbound and Down
Try to get in between 9.5:1 and 10:1 for pump gas.
Looks like you got a game plan. Report back once you get further down the road with it.
Looks like you got a game plan. Report back once you get further down the road with it.
How crazy would I be to throw a set of Vortec heads on here and go? Compression would be 9.01:1 as listed in this message, obviously horse power would be down but how bad? It's going to save me about $400 on heads, and I'm guessing at 9.01:1 I could run cheap gas? Obviously the trade off will be less power but how much less are we talking here is there a good way to give it an estimated guess? The whole reason aluminum heads came up in the first place is because I was worried about 'pinging' and heard you could run higher compression with them. If I were to go the Vortec head route it would save me from more pistons, cam swap, etc.
They have some issues with valve lift and geometry, and require a different rocker. Research it before you jump
That said they flow better on top than other stock heads. I wouldn’t pick them over standard SBC heads on my choice of aluminum and aftermarket
beags86
Eastbound and Down
Even at 9.5:1 your not close to pinging territory. The heads you had picked out are going to yield better number then the vortec heads.
Go aluminum, just find a slightly cheaper set.
How much are you going to to drive it?
Do you want to have fun when you do?
You can get 400hp out of vortec heads but it's not as easy.
Go aluminum, just find a slightly cheaper set.
How much are you going to to drive it?
Do you want to have fun when you do?
You can get 400hp out of vortec heads but it's not as easy.
