Hey everyone, I'm new around here but I'm looking at trying to get some power in my 403 that's in my 79 Formula without breaking the bank. If anyone has a good place to start my list, that would be greatly appreciated.

 

True dual exhaust in conjuction with swapping the factory 2.41 rear to a 3.42 rear.

It will feel like a completely different car.

 

X2 on the dual exhaust and better rear gear. A little higher stall torque converter will also help launch off the line. If you don't like 3000 rpm highway speeds, a TH2004R is also a best of both worlds. Bolts right in place of your TH350 but will need mild modifications to live with a stock 403. The 2.74 first gear, minimum 1900 stall converter and .68 overdrive gear make for much more fun driving.

 

Welcome. Nice bird.
Along with the above mentioned mods consider super tuning what you have before throwing parts at it.
But first make sure all safety items are up to the task. Tires older then 10 should be replaced. Rubber brake and fuel lines should be replaced. Chassis components should be inspected and replaced as needed.

Look for any vacuum leaks due to aged hoses, loose throttle shafts on the carb etc...
Service the entire car...Replace/flush ALL fluids...yes... brake, power steering, trans, rear dif...et al. Use the correct replacement fluids. Not one size fits all garbage.

Tune the 3 ignition timing events...base timing, vacuum and centrifugal advance.
Give it as much base timing as it will tolerate. Ignore the factory suggested setting.
Use good ignition wires say Taylor spiral cores and NGK plugs.
Adjust the air fuel mix to achieve the highest vacuum signal possible.

Next study up on how to "super tune" a Rochester Quadrajet...if its still there.
Make sure the carb is fully opening you depress the gas pedal.
Use ethanol free higher octane gas.
Verify the fuel and air filters are clean.

Reduce the heat under the carb by installing an insulation/isolation gasket and fully or partially block off the heat riser crossover.
Rebuild vs replacing worn parts. Especially if the parts are original. Steer clear of big box chineasium parts houses parts. Source USA made when ever possible. Find a good Pontiac restoration supplier.

 

Thank you everyone for the information so far! I have learned so much in the past 24 hours!

 

If it's currently running and driving, leave it except basic tune up stuff (Carb, wires, plugs, distributor, timing chain). You're in California so what are your restrictions on exhaust? If you can put headers on it that's an easy 15hp. A rear gear change would make a night and day difference in the car and won't have to worry about anything emissions related. 3.23 or 3.42.

Using an Edelbrock performer or a 307 A4 intake manifold would take off 25lb from the front end. I see you don't have the shaker hood so you could use a Performer RPM.

If you're willing to spend more ($2k or so) for another probably 50hp, keep reading.

Cylinder heads, 330 have the smallest chambers but once again goes into if you must have the EGR tubes. If you don't have to worry about that, #3, #4, #5, #6, #7 or #7a bolt on with the head bolt holes drilled to 17/32 and should bump your compression to ~8.5:1 instead of 7.9. Replace the valves with 2.07.1.68.

Swap in a better camshaft. I think Mark's (CutlassEFI) favorite is an Erson TQ40?

 

I've currently got it registered on historic plates in MD, so no inspections. I've been reading many good things about Edelbrock's intake manifold along with the many options for heads. I've just been having trouble finding a set of 7A's in the area. Thank you for the help!

 

Start with a leak down or compression test to determine engine condition, check the timing chain for excess slack and check for a nylon cam gear.

 

#8 heads are still a 7/16 bolt hole. The solid main blocks go all the way up to '76.

 

Why do you need 7A heads specifically? 5, 6, 7, and 7A (69-72) heads are nearly identical and generally the same price and availability.

Can use #3, or #4 330 heads as well and have a little bit smaller combustion chambers.

Any factory head worth installing will require head bolt holes to be drilled to 17/32 as well as the dowel pin hole opened to 5/16 (?) if I remember correctly.

Additionally, any parts store replacement head gasket is .024" thicker than the factory. Recommend cutting whatever cylinder head you use around that much to make up the difference so you don't lose any compression.

 

I've just read the most about those in particular, but I'll read up more on the other heads. All of this information excites me, thank you!

 

Thank you! I'll have to connect with him, it is nice having the weekends to drive around and do what I can to my Firebird before it's time to go back.

 

7a heads have hardened valve seats (allegedly) otherwise they’re all similar from 4-7. Compression is going to be weak link. It will limit your cam choices and overall performance. So heads should be first on the list. I wouldn’t waste any time on the Quadrajet or any Edlebrock. Go for a Holley and you’ll have the adjustability you’ll need to keep it running right. You might get 10hp from a true dual exhaust but without the heads to let the exhaust out you aren’t getting full potential of the exhaust. You could easily get 30hp from heads and a cam.

 

Learned this from JoeP, the hardened seats are induction hardened at the factory vs. a hardened insert and that grinding the valve seat removes the induction hardened surface so your right back where you started. At that point hardened inserts are needed.

Someone that knows correct me if I'm wrong on this.

 

True on both accounts but consider how long it takes to sink a valve. I've never actually seen a sunk valve in an Oldsmobile in the couple hundred I've disassembled in the last 20 years. Limited experience, sure, but as little as these cars are driven, you'll be fine without steel insert or hardened seats.

 

Thanks for the confirmation bb77...was trying to guide the OP to not go on a long search for heads with factory hardened seats such as 7a's when there are other good options available.
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