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#1
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#66 heads
I've acquired a 455, it has casting #66 heads. They have press-in rocker studs and bolt-on guide-plates.
My question is: The pad that the guide-plates set on. Is it the same height as a head that came equipped with screw-in studs from the factory? I'm concerned about clearance between the bottom of stock style rocker arms and the hex on the stud. |
#2
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Same height.
Had a set myself that I converted to screw in studs. The only heads that need the stud bosses milled to use screw in studs with the bottom hex are the early heads that don’t use guide plates.
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1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/2.56 2002 WS6 Convertible LS1/4L60E/3.23 |
#3
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Big Chamber heads. Pump gas friendly
I sold a set recently that had been converted to screw in studs and were date coded for the guy's car.
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You never know what I might have that you are looking for. EMAIL me. Also check out my other ads here on PY. Just click on user name to view other ads. USPS Money Orders or Wal-Mart to Wal-Mart money gram wire transfer -preferred payments. If Payment doesn't show up in 3-4 days, I move on to the next person that wants it. Serious Inquiries Only - Shipping Isn't Free. |
#4
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For b-man
Thanks for the answer man I appreciate the info. Did you use the existing guide-plates or did you replace them? |
#5
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[QUOTE=thepontiacman;6052669]Big Chamber heads. Pump gas friendly
If they aren't cracked, I will have them milled around .060" and the intake side as necessary. With .027" gaskets I should get close to 9:1. |
#6
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65,
6X heads are plentiful and much better heads to start with. Before you go and spend $$$ on your 66's you mean gut shop around...
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1977 Black Trans Am 180 HP Auto, essentially base model T/A. I'm the original owner, purchased May 7, 1977. Shut it off Shut it off Buddy, I just shut your Prius down... |
#7
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I used the existing guide plates, they’re the same ones used on heads with screw in studs. The studs will now hold the guide plates down, no need for the center hold down bolt used on press in stud applications.
__________________
1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/2.56 2002 WS6 Convertible LS1/4L60E/3.23 |
#8
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Thanks again
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#9
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Quote:
A guy on Craigslist has a set of 4X for $100 but he don't know what they are off of. If they are from a 400 they would be ideal. Or like you say 6X-8's would do as well. I have some nicely rebuilt 6X-4's, but don't want that much compression. 91 octane is what is available here, and I will be happy with 9:1ish. |
#10
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When you add up the cost of tapping for screw in studs and the added cost of conversion studs with 1/2-13 threads on the bottom ($100) plus the heavy milling to try to get 9:1 compression and expensive Cometic .027” gaskets ($200) the 6X-8 heads are a better way to go.
No expensive conversion studs and no tapping needed for the 6X-8 heads and no heavy milling requiring a cut on the intake side of the head. If your engine is apart you may be able to cut a small dish in your pistons to utilize the 6X-4 heads. Food for thought.
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1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/2.56 2002 WS6 Convertible LS1/4L60E/3.23 |
#11
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Quote:
It appears to be a recent rebuild, not sure if I'm going to tear down the bottom end. To my surprise, it has .025" deck clearance, .030" Silvolite pistons. It has the piston size markings on the deck from the factory so it has not been decked. What would you think about opening up the combustion chambers a little? I have a couple good books by Jim Hand and Pete McCarthy one of them illustrates where to and not to take material out. I like the ideas. If I replaced the rods I could mod the pistons, because I would have to balance it anyway. I wish I could replace the rod bolts without taking them out but I've heard the ARP's will distort the rods so they have to be honed. |
#12
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You should not need to mill anything to get 9 to 1 compression with 6X heads. 6x-8-100cc's, deck clearance-6cc, gasket-10cc's. 116cc's with a 455 is 9.0 compression.
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#13
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116's with 455 is around 8:1.
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#14
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My 455 also has the 66's. Unfortunately for me, mine came with the cheap cast pistons that have the bevel around the edge of the piston, lowering the CR even more. My final CR is less than 8.0:1.
But with a set of Tri-Y headers, a really good exhaust system, and a custom low-lift HFT cam, it runs pretty decent. With a stock torque converter and a 3.08 posi, it will smoke the tires off-idle, even at just part -throttle. The motor is DONE by 4800rpm, but it has killer torque and runs great on the cheapest gas I can find.
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'73 T/A (clone). Low budget stock headed 8.3:1 455, 222/242 116lsa .443/.435 cam. FAST Sportsman EFI, 315rwhp/385rwtq on 87 octane. 13.12 @103.2, 1.91 60'. '67 Firebird [sold], ; 11.27 @ 119.61, 7.167 @ 96.07, with UD 280/280 (108LSA/ 109 ICL)solid cam. [1.537, 7.233 @93.61, 11.46 @ 115.4 w/ old UD 288/296 108 hydraulic cam] Feb '05 HPP, home-ported "16" D-ports, dished pistons (pump gas only), 3.42 gears, 275/60 DR's, 750DP, T2, full exhaust My webpage http://lnlpd.com/home |
#15
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One cylinder volume is 932 cc's. 455 cu in is 7456 cc's
116 + 932 = 1048 1048 ÷ 116 = 9.03 |
#16
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Quote:
Actual CR ends up right around 8.0:1
__________________
'73 T/A (clone). Low budget stock headed 8.3:1 455, 222/242 116lsa .443/.435 cam. FAST Sportsman EFI, 315rwhp/385rwtq on 87 octane. 13.12 @103.2, 1.91 60'. '67 Firebird [sold], ; 11.27 @ 119.61, 7.167 @ 96.07, with UD 280/280 (108LSA/ 109 ICL)solid cam. [1.537, 7.233 @93.61, 11.46 @ 115.4 w/ old UD 288/296 108 hydraulic cam] Feb '05 HPP, home-ported "16" D-ports, dished pistons (pump gas only), 3.42 gears, 275/60 DR's, 750DP, T2, full exhaust My webpage http://lnlpd.com/home |
#17
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Quote:
I'm worried about the stock rods though. Might get them honed with ARP bolts. Cost would be $180 for that. I'm curious the specs of your custom cam. |
#18
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You are missing a part of your equation. You have to add for piston dish (valve reliefs in this case), head gasket and deck clearance.
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#19
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222/242 @ .050", .443"/.435" valve lift, 116 LSA, ICL target was 111 but it ended up at 112.
The motor had a .454" lift cam in it, when I got it. There was no wear on the cam or lifters, so I knew that whatever the springs were, they were fine for up to .454" lift.
__________________
'73 T/A (clone). Low budget stock headed 8.3:1 455, 222/242 116lsa .443/.435 cam. FAST Sportsman EFI, 315rwhp/385rwtq on 87 octane. 13.12 @103.2, 1.91 60'. '67 Firebird [sold], ; 11.27 @ 119.61, 7.167 @ 96.07, with UD 280/280 (108LSA/ 109 ICL)solid cam. [1.537, 7.233 @93.61, 11.46 @ 115.4 w/ old UD 288/296 108 hydraulic cam] Feb '05 HPP, home-ported "16" D-ports, dished pistons (pump gas only), 3.42 gears, 275/60 DR's, 750DP, T2, full exhaust My webpage http://lnlpd.com/home |
#20
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Thanks Lee !
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