#21  
Old 06-07-2019, 08:08 PM
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Originally Posted by David Brown View Post
My 455 originally had #15 heads. I have owned this car since 1979, when "real" high octane leaded gas was still available. When they phased it out leaded and replaced it with 93 octane unleaded, I had a continual pinging problem. I struggled with that for a couple years. Back off the timing and it ran hot. Octane boosters were for the most part snake oil. For a street driven car, it was a major pain to be constantly chasing the right sweet spot to eliminate the ping and not kill performance. The only fix was head replacement to lower compression. I ran 1971 #96 and they were great until previous repaired cracks let loose. Now I run 6X and have about 9.25 to 1. . If you plan a compression increase, make sure you get a cam that will control the pre-ignition. If it's for the strip, then you probably will buy race gas.
Does your engine still have the stock cam in it??? Just wondering...how does it perform with the 6X heads?

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  #22  
Old 06-08-2019, 10:20 AM
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Date code is G038
So July 3 of 68
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  #23  
Old 06-08-2019, 03:17 PM
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A390GT- Are both sets of 15 heads 68 casting dates? According to the chart I posted, '68 15 heads have 75 cc combustion chambers and the '70 15 heads have 87 cc's. Both are small valve with pressed rocker studs.

Dennis

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Old 06-08-2019, 10:08 PM
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The ye engine from the 68 bonneville has a I 217 and a I 297
Head
So they are both from sept of 67

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Old 06-10-2019, 06:34 AM
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OK, so they are both (sets) are high compression (75 cc) small valve press-in stud heads. Like suggested earlier, you could have the studs replaced with threaded studs, or have them pinned. The studs that are pulling out would have to be reseated and the pinning process costs about $5.00 per stud to do, so about $80 to $100...not much more money and you've paid for the better threaded studs. I do like the idea of finding some 6X-4 heads and a Summit 2800 cam for torque. That would lower your compression ration to a manageable 8.5 in a 400 or 428 (with dished pistons) at around 90 cc's when cut a bit.

Dennis

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Old 06-10-2019, 08:01 AM
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I’m going to keep the wagon stock with the 15’s and a 641 cam and timing set
I’m looking for a good machine shop to bring the heads to in Northern New Jersey. If I don’t find one I’ll put the other heads on.
They guy I used to use retired a few years back

Do you think it will ping with the 2bbl on it.

The YE Do 6x heads have the d-port?

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Old 06-10-2019, 12:29 PM
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It will ping with either 2 or 4-bbl inductions with a very mild cam and hi compression (9.9 - 10.0 actual probably).

Yes, all 6X heads (4, 6, & 8's) are D-port exhausts.

Dennis

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Old 06-10-2019, 04:57 PM
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I’ll keep my eye out for a set of 6x for the YE that’s going in the catalina hardtop.

Its another YC with 15 heads. I put a stock 4bbl cam and intake on in it l15 years ago and it pinged since. I pulled some timing to make it livable

I’d really like to get the butler top end, would 87cc dump the compression too much? 3,800 is a tad over my budget
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Old 06-11-2019, 12:36 PM
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No, the 87 cc aluminum heads would increase the compression a little bit, may to around 8.8-ish, but the aluminum head needs another 0.5 increase of compression to be comparable to the iron head in efficiency. They will certainly flow much better, but I think they are overkill on an engine like yours and you can spend the money on better things...cam & lifters, better exhaust, and improving the intake system...and still have money in your pocket.

Dennis

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Old 08-29-2019, 05:37 PM
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So I’m looking to use the 11 bolt timing cover and I thought I had the correct water pump (1969) but it looks like it’s an inch longer than the 8 bolt setup.
What did I do wrong or is this correct and I just need pulleys now?
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Old 08-29-2019, 06:08 PM
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There are two 69 water pumps. The early one is shorter than the later version that is interchangeable throughout the 70’s.

Simplest solution is to just get a used mid 69-79 water pump pulley.

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  #32  
Old 08-29-2019, 06:14 PM
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Ok I thought I got the early one. The pan fit is real tight too
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  #33  
Old 08-29-2019, 10:11 PM
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Here's my too cents. If your looking for a good machine shop and your in northern NJ and if your not that far from Port Jervis NY, Five star crankshaft, tell Al Rocco sent you. If your looking for new head these are two good heads to look for and both are large valves 1971 96 screw in studs and 1967 61. The 61 heads are open chamber and 10.5 compression press in studs Fro what I read the 61 heads were proto types chamber design for RA 2. The 91 compression is about 10. Summit sell a good timing chain and its US made Fel pro blue strip HP gasket set. You would want a low rpm torque cam from 1200 to 1800 to about 56oo RPM range

  #34  
Old 09-06-2019, 04:39 PM
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How off center are the lifters with the cam on these 400’s?

I thought there was something wrong with the new cam but I noticed the same offset ( not centered) with the other engine with the original cam / lifters still in it
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  #35  
Old 09-06-2019, 10:17 PM
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That's the way they are supposed to be. Only half of the bottom of the lifter contacts the cam lobe. The bottom of the lifter is ever so slightly convex. The cam lobe is not square with the centerline of the cam, either. It is ground...I guess the word is slanted..the back of the lobe is slightly taller than the front. The lifter actually roles (it has to or it will wear out very quickly) along the surface of the lobe. The importance of the cam break in, for the first 30 minutes is vital for a long lasting cam and lifters.
I could go on...

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  #36  
Old 09-07-2019, 07:44 AM
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Ok, It’s been a while since I did one.
The last engines had roller cams so I guess that’s what threw me off.

  #37  
Old 10-03-2019, 10:08 AM
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Engine is back in the wagon. What are you guys using for break in oil?

  #38  
Old 10-05-2019, 10:16 PM
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Quote:
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Engine is back in the wagon. What are you guys using for break in oil?
https://www.amazon.com/Lucas-Oil-106...9AGFNBW4F5SN91

  #39  
Old 10-05-2019, 11:22 PM
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That or Brad Penn, there's others.. Joe Gibbs, Comp cams I believe has a brand. Could buy regular motor oil, and buy zinc additive.

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