[ScreamingChicken]

I am getting ready to start disassembling my 74 SD T/A. The body is being sent off to be stripped, body work done and a fresh coat of Buccaneer applied. While that work is being done the engine will be left in my hands. (as will several 100 other pieces) I want your opinions concerning the engine. To start off this car will be a street car and I want to be able to return it to stock if I ever need to. I would be happy if the car turned mid to high 13's in the quarter. I would like to keep the motor as stock as possible internally. I need to know if what I have planned will achieve my goal. I plan on installing a set of Hooker Super Comps, an Edelbrock RPM Performer intake, Holley or Demon Carb, electric fuel pump, Flowmaster ForceII 2.5 exhaust system and replacing the 3.08 axle with a 3.42. The ignition will be upgraded to a Petronix ignitor system as opposed to the points. I was also wondering if it would be worth it to install a minor (2500) stall convertor in the Turbo 400, it already has a B&M shift kit installed. The engine is 100% stock now but I want it to have that extra kick. So please give me some of your thoughts or ideas for this SD motor. Let me know if my ideas are not worth doing as well, I want your opinions, I will not take offense if my ideas are not worth it.

[ScreamingChicken]

I am getting ready to start disassembling my 74 SD T/A. The body is being sent off to be stripped, body work done and a fresh coat of Buccaneer applied. While that work is being done the engine will be left in my hands. (as will several 100 other pieces) I want your opinions concerning the engine. To start off this car will be a street car and I want to be able to return it to stock if I ever need to. I would be happy if the car turned mid to high 13's in the quarter. I would like to keep the motor as stock as possible internally. I need to know if what I have planned will achieve my goal. I plan on installing a set of Hooker Super Comps, an Edelbrock RPM Performer intake, Holley or Demon Carb, electric fuel pump, Flowmaster ForceII 2.5 exhaust system and replacing the 3.08 axle with a 3.42. The ignition will be upgraded to a Petronix ignitor system as opposed to the points. I was also wondering if it would be worth it to install a minor (2500) stall convertor in the Turbo 400, it already has a B&M shift kit installed. The engine is 100% stock now but I want it to have that extra kick. So please give me some of your thoughts or ideas for this SD motor. Let me know if my ideas are not worth doing as well, I want your opinions, I will not take offense if my ideas are not worth it.

[Rocky Rotella]

I don't want to pick apart your plan but I think you'd be better off reusing some of the factory items. I'd overlook the idea of headers and the RPM intake. If you're going to use the car mainly for street use, the stock SD manifolds are sufficient. Rather than use headers, look into a pair of Torque Tech's 2.5" mandrel bent pipes which are made to fit those specific manifolds. To that, mate your Flowmaster system.

Next, again with primarily street usage in mind, the stock cast iron SD intake is an excellent item. The RPM would mostly boost upper rpm pull BUT you can not run the factory choke set-up without some modification and the intake is much taller than stock so the scoop would have to be bolted to the hood or use a drop base air cleaner. Properly rebuilding the stock Q-jet and selecting the proper primary jets and rods along with .030" CC secondary rods would equal the performance of the Holley or E-carb on the street and quite possibly the strip. Also, while 3.42 is a great gear, the 3.08's are perfect for a 455, especially a torquey one. If you go with more cam, 3.42 is wise.

Another point is the Pertronix. I've heard numerous people who were dissatisfied with them and also problems with their longevity. They have a tendency to pulsate with the dwell and also burn out, leaving you with no spark. Recurving your stock points ignition on a Sun machine will get you the best bang. Replacing your points with Mallory 102 or 102X single points withthe dwell set at 28 is also a good move.

You probably do not need to swap the converter out but the L88 TH-400 converter is a great choice and a direct bolt in. I hear Continental makes super converters as well. I'd adviseusing a Delco SD replacement fuel pump. They're fairly high volume and cheap. Use it until you know you need more fuel.

Honestly, if I had your SD, I'd mill the heads .050" to boost compression, have a quality multi-angle vavle job installed, set spring height correctly and bolt them on. You can resue the stock cam but it's short on lift. The stock .407/.407" lift only jumps to .447/.447" with the addition of 1.65 rockers. From my point of view, Nunzi of Nunzi's Automotive offers some of the best cams on the market. We run his 2041(068 with higher lift and his tweaks) in my dad's 72 HO and the 2042(744 with higher lift and his tweaks) in my 76 Trans Am. I think you'd be very satisfied with the 2042 which is based on the cam in your SD. It's rated at 232/243@.050 with .460/.470" lift at 1.5. That alone would increase performance but adding 1.6 full roller rockers would get even more out of it allowing you to take advantage of the SD head flow. The 1.6 rockers would make the duration 235/246@.050" and take the lift to .490/.500".

I hate to shoot down all your plans but I truly see you spending money and not being totally satisfied with the car. You mentioned you want to be able to take it back to stock if needed. Why not optimize all the stock parts, tweak them a little and have a extremely hard running 74 SD Trans Am that looks all stock. I think you'd be surprised what can be accomplished with the factory parts. Both my dad and myself strive to keep our cars looking stock using all the stcok hardware but tweaking like I said above. Currently, Nunzi has a pair of 71 HO heads that he is doing for me. I love the rare factory parts and they're worth keeping. Chris Nash or "455HO" of the PY board has a stock bore 71 HO T/A. He had his heads cleaned up by Nunzi, has the 2041 Nunzi cam, 1.6 Nunzi rollers and the Flowmaster system you mentioned. On an otherwise stock set-up, through the HO/SD manifolds he runs 13.10's@109mph. That's pretty damn impressive for a stock appearing car. My dad has the same set-up and performance but in an automatic car.

Another choice is to contact Nunzi direct, he's had and still owns numerous SD cars. The guy's been in business for 40 years supertuning and building Pontiacs. He knows the SD inside out. I'll bet he'd recommend everything I did above. You can contact him at (718)837-1135.

These are just my ideas and I'm sure something are not what you expected. Let me know what you think about this. Rocky

[ScreamingChicken]

Rocky:

Thanks for the information! Its nice to hear that my stock parts will work just fine. I do not want to shell out money and the time for products that will only disappoint. I have contacted Nunzi and have a catalog that he sent me. Looking through the catalog I see the cam you are referring too. I see that he also recommends going to the 1.65 rockers as well as stiffer valve springs and different valves. The only problem is that my catalog does not have any prices, according to Nunzi they were out of price sheets. Do you happen to have an up to date copy that you could fax me or any idea what these parts run? Thanks again!

[Rocky Rotella]

Yup, sure do. I'll be at work this aftenoon between 1-4pm CST. If you could call me there I'll send the fax over. We can discuss a little more too. The SD cars have factory installed heavy duty valve springs and valves similar to the RAIV parts.

800-759-0360, just ask for me.

[jyeager]

Rocky, great advice. I agree with your advice 99 percent. I'd focus on a little head work and new cam. As far as the rpm intake goes, I wouldn't recommend it because of the hassles with the scoop, but I do believe that it will help on any 455 that is still breathing at 5500rpm (this implies good enough heads and cam). I believe the benefit is better than .1 sec. in the 1/4. I admit i'm trying to recollect the results of a back-to-back test done by Jim Hand, so I'm not sure on the number.
But that doesn't negate your advice. I don't think that benefit is worth it for this situation. Also, on a 455 I don't think the rpm manifold hurts the low-end since it's still a dual-plan manifold. (this would probably not be true of a smaller engine such as the 400).
Just my ramblings, let me know if you think I'm mistaken.
Take care,
Jeff.

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[Rocky Rotella]

Jeff, I agree with you too. Maybe great minds think alike? Wait, we're talking about me as part of this so scratch that last statement.

Anyway, I like the RPM intake. Like you mentioned, it does pull well above a certain point yet etain all the torque down low. I'd look into one if I didn't have the scoop issues. I think you're right about the heads too. A quality valve job will really let the heads flow better. Port work is something that is expensive and not totally necessary on the SD head. If either port needs work, it's definately the exhaust. Machining the heads will boost compression, that'll gain a few horses alone.

Either way, it'll be a hard running car when he gets it back together.