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Old 10-09-2014, 08:42 PM
SlowPoke SlowPoke is offline
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Default '73 SD restoration

Greetings Gents,I have a white 1973 SD-455 Trans Am which was my treat to myself when I graduated college that year. Went from a starving student to making a few bucks. Actually bought it in '74 from a starving dental school student after hunting relentlessly for a '73. I didn't like the body style changes made and would have "paid extra" to get a '73.

Anyway....I'm planning out how to restore it (engine has 38,000 miles)and I want more compression but don't want to be cutting any metal. It is worth more unshaven and while I plan to change the cam, rockers, lifters etc I'm keeping all of the old components for whoever owns it next. So,I'd like the opinion of the gang. I want to raise the compression ratio as much as I can without shaving and without changing from a flat top piston. I have a set of TRW's which have compression bumps on but as many publications suggest, they mess up the flame front travel and are not a good change.

Long, long ago and in a land far, far away I had a '65 Chevrolet 327 which I was able to get the compression ratio a few points higher without shaving by using shim-type head gaskets. It took some custom making of intake manifold gaskets to get the geometry perfect but it worked great. What do you think about this approach for my SD?
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Old 10-09-2014, 08:58 PM
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mockingbird812 mockingbird812 is offline
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Default Re: '73 SD restoration

Welcome aboard SlowPoke. Congrats on keeping her for 40 yrs. Pls post some as is pix and a few from back in the day! Thanks!
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Old 10-09-2014, 09:04 PM
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PeteLeathersac PeteLeathersac is offline
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Default Re: '73 SD restoration


Welcome aboard!
Your Super Duty brother NJSteve is a member here and I expect will find you shortly.
[img]<<GRAEMLIN_URL>>/beers.gif[/img]
~ Pete

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Old 10-09-2014, 09:14 PM
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Default Re: '73 SD restoration

You've had this car from almost new (bravo to you) and you plan on changing all the valve train so why are you worried about the &quot;value&quot; of the heads? You've had it this long...A little bit of milling does the SD-455 a lot of good - especially when combined with a set of JE aluminum pistons ( don't have the part # handy but I will look it up - SRP also makes a good SD piston #149721), and nobody but you has to be the wiser. Here is an old school article on an SD-455 '73 T/A and the work that went into getting it to go faster using stock parts. It is old tech but still some valuable information.

A gentleman by the name of Steve Shappaugh has forgotten more than I know about getting Super Dutys to perform and he would be worth talking to - look him up online. It's a great engine and with just a point of compression, a good ignition and traction aids, it is a &quot;real street sweeper&quot;.

















































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Old 10-10-2014, 11:50 AM
SlowPoke SlowPoke is offline
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Default Re: '73 SD restoration

mockingbird812, that ’69 Chevelle is the car I lusted after through high school. I lived in NJ until college and our street was on the edge of town, about 2 miles long. The guys 3 houses down had saved their money and bought an SS396/375 and I remember hot summer nights (no air conditioning in our house) with the windows open when they’d burn it out down our street after a bad date. Pure music.

Pete, thanks for the welcome. I’ll have to dig up some photos. No pics of her current condition until after some paint though. It was garage-kept until 2000 when we moved to Maine then it spent 3 years exposed to snow and weather until the garage was finished there. Building houses in Maine is not like any other state we’ve lived in. We live in arid Salt Lake City now and the dry weather is a good preservative for the metal.

Tracker, you’re echoing some of the mental debate I’ve had for the last 40 years….shaving or not. But my wife will likely live longer than I do and I want to leave her with as much money as possible. Then again, we’ve hauled this car all over the USA each time we move and I may decide to give it up myself after satisfying my curiosity of just how well it would do with some minor changes.

So far, my polling of collectors suggests milling the heads would lower the value. Now if when I take it apart, I find that the heads have warped then milling them would be the right thing to do and would increase its value over leaving it alone. Composite head gaskets are awfully thick so it seems a good way to do this but I don’t see many people writing about it which is why I’m asking for opinions. BTW, thanks for all the good info.

Does anyone know a current source for headers?
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Old 10-10-2014, 01:21 PM
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Default Re: '73 SD restoration

mill the heads, your wife will be fine. Hedmann makes great headers for Pontiacs - is this a 4-speed or an auto.?
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Old 10-10-2014, 01:24 PM
markinnaples markinnaples is offline
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Default Re: '73 SD restoration

SlowPoke, why not put the stock engine and tranny in storage and build a similar 455 that you can do whatever you want with it and not risk the $$$ loss of altering the original engine?

Just a thought, especially since the 70's T/A's are climbing in value rapidly these days.

Would love to see some pics.
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Old 10-10-2014, 10:06 PM
PLATINUM6BBL PLATINUM6BBL is offline
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Default Re: '73 SD restoration

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: markinnaples</div><div class="ubbcode-body">SlowPoke, why not put the stock engine and tranny in storage and build a similar 455 that you can do whatever you want with it and not risk the $$$ loss of altering the original engine?

Just a thought, especially since the 70's T/A's are climbing in value rapidly these days.

Would love to see some pics. </div></div>
Sadly I wish a kid I know took seriously the 72 H/O 4spd T/A that he inherited after his father passed. Wounded the engine within a few months, then left it sit outside for months (I barely remember it even seeing bad weather when his dad owned it) and I just heard that stacks of tires have fallen over onto it.
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Old 10-10-2014, 11:56 PM
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Default Re: '73 SD restoration

Welcome! Now go to the Pontiac portion of this website and start a thread on your car, there. [img]<<GRAEMLIN_URL>>/biggthumpup.gif[/img]

Here's a couple of my projects:

http://www.yenko.net/ubbthreads/ubbthrea...-tre#Post539528

http://www.yenko.net/ubbthreads/ubbt...eux#Post487291

and the monster thread of them all:

http://www.yenko.net/ubbthreads/ubbt...ta-new-project

I would not get high compression pistons. The low compression Pontiac round port engines do not respond like a other engines (Chevies in particular) where raising the compression makes more power. 455HOs and SD455s don't like them and don't respond well to them at all. You'll just make it slower and addicted to racing gas. If you peruse the second thread above, you will see that the 455HO I had, had those domed 10-1/2 to 1 forged pistons installed and preignited like a monster - to the point where it left visible wear on the rod bearings and the timing could not be retarded back far enough to stop the knocking. And it was actually faster after I rebuilt the engine and installed forged 8.4 to 1 pistons.

A proper blueprinting of the engine will get you where you want to be. Everyone who has thrown a set of headers on a round port car ends up complaining about the leaking gaskets/flanges and winds up going back to the manifolds which were some of <span style="text-decoration: underline">the</span> best flowing cast iron manifolds ever produced. The best bang for the buck is getting a true dual exhaust setup with an x-pipe and without the crossover muffler. Also, getting the carb tuned properly will amaze you. The jets and metering rods need to be richened up by at least 10% to offset the 10% ethanol in today's fuels. There is a good 20 horsepower in that carb just waiting to be unleashed with the proper settings.
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Old 10-11-2014, 10:54 PM
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KenMaisano KenMaisano is offline
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Default Re: '73 SD restoration

Its very easy to make a Pontiac fly if you build them correct. They have very small port area and a long stroke. So you build them around torque not RPMs. One of my daily drivers is this 70 T/A its 440 inches. I had to sleeve all Eight holes because someone let the block rust. So I under bored it, I didn't want to break into water or weaken the deck. Then I added some stroke. its 9.6 compression D Dish .040 piston to head clearance, The key on these motors are they Love Wide lobe centers.
Cam 230/238 114. at 38' timing it runs amazing on our California watered down 91 gas. Ported #12 Heads stock plenum worked cast iron intake, Cliffs QJet Carb, Ram Air products Exhaust manifolds with a Pypes transverse ex. system. With a 3.23 posi, stock converter T 400. This car gets a average of 17MPG and will blow the tires off. This car is super fun and now right flys.
https://www.facebook.com/video.php?v=561...e=2&amp;theater

Ken Maisano
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