Stock heads for increased compression

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Nov 24, 2006 | 01:50 AM

#11

thunder550

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From: Phoenix, AZ

Quote:

Originally Posted by 1slow01Z71

Back the timing off a bit and run a 160* t-stat with the 34" rad he has and the efans to keep her nice and cool. Doubt he would be able to tow with that setup but he could try.

If it was me I would just the throw the heads from Richard on now since it would be alot easier now and driving a low 9:1CR wouldnt be to bad, and he could always throw some nitrous on it

Just trying to save a little bit of money right now....and I'll make a little more power too N/A.

You think I'd have problems towing with 9.6:1 on 91 octane?

Nov 24, 2006 | 01:52 AM

#12

thunder550

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From: Phoenix, AZ

Damn those 243 heads are pricey

I think I'll just run my stock 317's for now, that would be cheapest. I'll be at 8.85:1 according to the Diamond compression calculator. Think that'll be ok, or is that getting to be too low?

4.03 bore
4.00 stroke
6.125 rods
4.125 gasket bore
.03 head gasket
9.23 deck height
.3 ring spacing from top of piston
72cc heads
28cc piston dish
.006 piston above deck height at TDC

Nov 24, 2006 | 09:12 AM

#13

desTRUCKtive

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From: Tucson AZ

If you wanted to you can mill the 317 down about 30 thousanths and then put a thinner gasket and that will raise your compression a little.

Nov 24, 2006 | 11:22 AM

#14

1slow01Z71

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If you are going to put 317s on there you might as well put Richards heads on there and save the trouble of dealing with a head swap in the truck. 9.6 should be fin, did you have detonation with the LQ9? If not I doubt you would with the 9.6.

Nov 24, 2006 | 11:35 AM

#15

thunder550

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No, never had a problem with detonation.

Nov 24, 2006 | 09:42 PM

#16

BigTex

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From: East of Dallas

Exactly. Unless you plan in huge amounts of boost, then you'd be plenty safe going with a 9.5+ CR combo. The other part of that equation is the cam choice. Its pretty small for a 408 with boost. Your dynamic CR will be higher with a smaller cam.