I'm new to this site and to the world of the firebirds. I just picked up a 1969 firebird 350 2bbl 9:2:1 compression with the stock 265 hp, in an automatic, all stock except for dual Flowmaster exhaust the car has 61,000 miles and is in mint condition. It goes good for what it is and its a numbers matching car and great for cruising the streets - but I want the power level up to around 350 hp and add tons of low end torque. I've heard many conflicting stories from a lot of people regarding this motor. Some claim that it can be modified to produce that power and a lot claim it can not and not to even bother with it.
My question is 1st off can I get 350 hp out of this motor? And if so what would be the proper parts I would require...such as Carb (carb size), Intake style and manufacturer, Cam and cam manufacturer, Heads, Headers, distributor....etc. In the classic Industries catalog they have a wide assortment of cam's carb, and Intakes, but no cylinder heads. This is where I was thinking of purchasing these performance parts but I don’t have any idea what will work with what and above all work properly.
If anyone can help it would be greatly appreciated.
your engine can be upgraded to receive edelbrocks performer package which can give you up to 450 total horsepower under the hood. this is a complete package designed for those who dont know how to put a package together. it includes the heads, cam, intake, carb, and generally all necessary hardware available to install the package. go with a roller assembly and see a difference in your engines pedal response.
Andy
due to budget cutbacks, the light at the end of the tunnel has been disconnected for non payment.
No doubt. Call Edelbrock and they set you right up. I've ordered matching carb, intake, cam, timing chain and gear ect.. Tell them what you have and what you want to do and they make a package. That was before they sold heads. Now that you can get the heads too I bet they have some really nice packages.
So I just call Edelbrock and let them know what’s in my car and they build me or match a kit for my motor brining it up to 350HP? Do you happen to have the phone number?
To offer a desenting opinion, I am not a big fan of the Edelbrock packages, cams are generic, carbs have problems, heads and intakes are great. For your car, I doubt you are ready to change heads. Consider a stock 4 barrel intake (or Ed. Performer) and a rebuilt Qjet (check with Cliff Ruggles), a high lift version of 068 cam (summit K2801) and ram air exhaust manifolds for that stock appearance and good boost in useable horsepower and torque.
Hey thanks for your input it’s much appreciated. So the Edelbrock cams are pretty generic….I have heard that they don’t make much power over stock from people. I’m looking for a cam that will deliver low and mid range torque as well as HP with a sweet sound at idle. What do you think of this combo?
65O Holley carb Edelbrock Performer intake Summit K2801 Cam Edelbrock Heads MSD Distributor Stock manifolds or possibly a set of aftermarket hearers
I’d be interested in your feed back - Plus car already has dual flowmaster set up
If you want to spend the money on Edelbrock heads, you would probably want to run headers to take advantage of the extra flow. The KRE aluminum D-ports may be worth looking at as well. That cam would also limit the heads as well. You might want to jump on the Performance Years BB to search expereince with diff combos. That is a lot of money to spend for heads to bolt on a stock bottem end.
Never had a problem with Edelbrock cams or carbs, especially the carbs. Used quite a few. They work great right out of the box. An Edelbrock package got me to 12 second quarter mile times with street tires. Maybe you are looking for more than that. Your list above looks great except I would put the Edelbrock carb in the list. Much better suited than the small Holley or the Rochester that's good for originality IMO.
What exactly do you have done to your firebird’s motor to get in the 12 second range Jim - that’s basically where I want my car to be as well. Is you’re automatic or stick? What gear ratio
I have built many! Which one? You get the Edelbrock package with the heads and you are there. All you are going to need are traction bars and BFG drag radials. I like the 400 auto with 3.55's.
No. I like more cubes. I would recommend more cubes unless you are dead set on the 350. Not saying that there's anything wrong with a 350. It's just a little easier with more cubes.
The 350 has a smaller bore than the 400, restricting the size of valves that you can use. They both have the same stroke, which means that they will turn about the same rpm, so the 400 will make more power because of better flow and more cubes. Like Jim says, easier with a 400.
The Edelbrock package on a 400 will make around 430-450 hp on the dyno if everything else is done right.
I would look into the KRE heads for the reason that they are D-port heads. This will make things a bit cheaper regarding exhaust manifolds or headers. Round port headers a PITA & the RA manifolds are VERY expensive.
You won't have to get too wild cam-wise to get 350 hp out of the 350. A 068 profile cam will get you there. Try to keep compression ratio around 9.5 to 10 to run pump gas.
Is it a 2-speed tranny? If so, you will need to change to a TH-350 with a good shift kit to handle the power. Besides, the 2-speed sucks!! Hope this helps!
Hi Steve where can you buy KRE heads from? By the way the tranny is a TH-350 in my car...what kind of carb and size, intake and model, and distributor do you recommend?
The KRE's are a step up. Here's there site. http://www.krepower.com/ You could still use the Edelbrock package with the KRE's. It would be interesting to know what Kaufman(KRE) recommends.
Hey I e-mailed Kaufman - this is what he recomended:
George, You can make 350 hp out of this engine.
700 Holley carb Torker II or RPM Performer intake Crower 60210 camshaft 1st. pick would be our Alum. d-port heads 2nd. pick would be later model 1960's cast iron heads. 1 3/4" 4 tube headers (Hedman would be fine). MSD dist.
Now to make all this work in the car you will need some rear end gears of app. 3.55 to 4.11. If it's an automatic then you will need a converter of app. 2500-3000 stall.
I wouldn't argue with him. I just picked up some good info on these heads too. You can run 93 octane with stock pistons and 72 cc chambers. That's 10.5 to 1 and only 93 octane. Serious food for thought!
I have a 1968 350 in my 1969 Bird. When I bought it it was a 2bbl with #17 heads, an ST300 two speed automatic and 2.79:1 gears. Needless to say, it was a pig.
I put a Quadrajet on it first, and the improvement was worth the effort, but not all that dramatic. It sure sounded better when the secondaries opened up.
Next, I replaced the 2 speed with a TH350 with a shift kit. The lower first gear and closer gear spacing between the 3 gears made a huge difference in driveability. The throttle response was better everywhere just because it seemed to be in the right gear all the time.
Then I upgraded to #16 heads and an aftermarket cam with the following specs: lift .420/.443 duration @.050 204/214 (270/280 adv) overlap 51 degrees
I love the performance now. There's no way it's 350 hp but it's lots of fun. Pontiac advertised 325 hp for their 350 HO in '69. Mine would need 3.55:1 gears to perform like a 350 HO, but trust me it's nothing like the pig it was. Now the rear tires break loose often enough to remind the neighbors that I have maturity issues.
Go as far as you want but be careful with recommendations for too much cam, carburetor, or anything else out of balance.
Hey John - Your car sounds like tons of fun. I checked out the pics of your car, its very clean….nice job
You know I thought the same thing about to much cam, carb, and Intake....but all engine builders I've spoken with tell me to go with the Edelbrock R.P.M. Intake (up to 6500RPM) and a 650cfm - 700cfm carb.....but I think to my self why do I need that big of a carb...600cfm-650cfm with a 6500 RPM Intake sounds doesn’t sound right to me. A straight 4bbl with no double pump and the regular performer intake (up to 5500 RPM) with an 068 cam plus headers and MSD disturber should be perfect - but they all tell me go high RPM on the intake and 650-700 on the carb which I personally think is to big....but again these guys are the pros so I guess I’ll take there word for it.
Thanks,
George
Hey Jim Edelbrock contacted me back – unfortunately there performer packages are only for 389’s – 455’s not for 350’s. The only things they sell for 350’s are the carb’s intake and a cam. Edelbrock really doesn’t have much for Pontiac 350’s – pretty pathetic if you ask me. But what are you gonna do.
In a book by Jason Scott, called How to Rebuild and Modify Your Muscle Car, there's a formula for how many cfm your engine should require from its carburetor:
carb cfm = ((engine cid x max rpm)/3,456) x volumetric efficiency
with this formula, you can calculate:
carb cfm = ((350 x 6,000)/3,456) x 0.80 = 486 cfm
My Quadrajet is rated at around 700 cfm, but it has vacuum secondaries. Vacuum secondaries only open as much as the engine needs them to open. Despite the formula, we can coax 'em open! I recommend that you use a carb with vacuum secondaries.
In the Winter 2002 issue of Hot Rod Engines, there's an article called The Other 350's - Pontiac. In this article, Jim Butler advises you to use 670 heads because the big 2.11 inch intake valves are set deep in the 72 cc closed chambers. In the same article, H-O Enterprises suggests '68 and '69 small valve heads off of 400's and 428's due to their small 72 cc combustion chambers and no valve shrouding with the small cylinder bore diameter. Finally, SD Performance recommends taking #47 or #11 castings, milling them .020", changing the intake valve seat angle to 30 degrees, mild intake side porting, and a 30 degree three-angle exhaust valve job. For more power, SD Performance says go to 2.05 intake valves and 1.71 inch exhaust valves. All three Pontiac experts in the article recommend less (advertised)cam duration than the Pontiac "S" cam. (288/302)
All I did was add a Quadrajet, slap on a set of big valve - small chamber heads, and shove in a mild cam that a friend didn't want. It's running great.
