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Pontiac - Boost Turbo, supercharged, Nitrous, EFI & other Power Adders discussed here. |
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#1
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'68 17s vs. '74 46s (GTO Screw In Stud Version) For Boosted Small Bore V8
Building a boosted small bore v8. My head options are 17s or 46s, as shown in the title. Pros and cons of each have me torn. Thoughts?
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#2
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Both are good heads...
Alot would depend how much work you want to put in them... they flow about the same stock... max ported the 46's shallower short turn limits it a bit more than an earlier head if plans include .600 lift or more. However, street ported they are close enough not to matter especially if boosted. The chamber size difference might be difference between runnin a flat top piston or dished(which usually costs more and weighs a tid more). Piston availability might be a deciding factor... if plans are 93 octane pump, E85, Race gas or Methanol chamber size would matter. Boosted on pump gas Stay near 8:1 range with iron... The 17's need to be converted to screw in studs. (NBD) I'm looking for a set of #17 heads(or 68 #15's or #18's or 69 #46 or #47) if you want to part with them. Dont need the valves or hardware, just sound castings.(I need a smaller chamber for a high compression build I have in mind but want to start with small valve) |
#3
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I think I'll go with 46s to save a compression point. I don't have plans for major porting, just boosted to 450 - 500 hp.
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#4
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Back to using the 17s. I think off boost feel will suck with the lower compression 46s. Being primarily a street car, 8.6:1 off boost compression has to be better.
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