I bought my 68 GS 350, a few months ago and I also bought a 73 455 motor from a friend. The 350 is the original motor for the car but, it has been rebuilt with low comp. pistons so the previous owner could drive it on reg. unleaded. I want the car to be fast and fun. I am not worried about a smooth idle or scaring small children. I would like to be able to pull down some low 12 to high 11 sec. 1/4 mile times and still be able to drive it to the track and run on 94 octane fuel. I have thought of putting a 4-speed in the car as well since the original trans. has been replaced already it isn't #'s matching any more. Or should I try to find a 68 2 speed trans and put it back. Are they any good. what experiences have you guys had? What combo. will work to get me where I want to be? Chris
Go with the 455 and the auto tranny you have, a 4 speed conversion is pretty expensive by the time you add up all the hard to find parts!
Hi Chris, I'm no expert, but I do have some experience asking these same types of questions and from what I've been told the 455 is the way to go. That said, you'll still need to sink some serious dough into a 455 to "reliably" go low 12's high 11's. I was told to achieve high 12's even with my original 400 that it was probably more worth going to a 455, which I did. Don't have the car back yet, but the engine is a mild one anyway. I think I'll be happy with mid 13's for now. It's a 73 block with stage 1 heads and a mild cam.
can I achieve this with cast iron heads or would I be better off looking into Aluminum ones? Would I have to do too much work to the iron heads to make it worth the cash or are the aluminum ones a better way to go? I know It takes money to make horsepower, I do this alot, nut what is the easiest most cost effective route, should I look for used stuff? is there much out there? Chris
You can definitely acheive the times you want with those heads. I think there's a couple of people who run in the 9's with iron heads. Aluminum ones are great if you just want to bolt something on and go fast. The only used Al heads you'll probably find are Stage 2's as the Stage 1's are rather new and no one wants to give them up yet. You should know Stage 2's require headers and exhaust manifolds are not compatible. It's general knowlege that most of the power that can be added can be from the heads. There are a few good Buick head porters out there. I won't campaign any as I haven't used their services. You could do it yourself. My buddy has had good luck doing it in his garage. He recently took a stock 70 455 ported the heads and put them back on with the original head gaskets. He has the motor in a 70 Skylark with a Th-350 and 3.90 rear and turned 13.0's. This is all stock motor, even the cam and the exhaust manifolds, in a rather light car. He also uses stock valves, they are backcut however. This is a perfect example of the value of good head porting. If you are going to spend the money, spend it on the heads. If the bottom end is good and your in a money crunch, don't spend much on it. You may want to stick a cam in there though. 73 cams are poor. You can up the compression at another time. You may not want too at all, gas prices are outrageous. That's my 2 cents.
I wouldn't try to ruun exhaust manifolds on any performance car. That defeats the purpose of al the work done to increase the flow of the heads, it's like shoving a cork in the tail pipe.I don't know what a used set of aluminum heads would cost, any input? I would rather just bolt a set on than have to wiat on someone to port a set of cast heads, plus the benefits of aluminum in weight savings and heat dissipation. The # 7 rod bearing in the 455 is toast so I will have to redo the bottom half. I will be looking for a set of light pistons and some good rods as well. And I will probably give my buddy Jim over at Racer Brown a call for the cam. If youv'e never tried one of there cams you should. the custom grind every one to fit your combination. I have had 4 of them in different cars abd they have always been excelent. CHRIS
aluminum heads are about $2500 ready to run. You would spend close to that having iron heads done to the same level, so I'd go straight to aluminum, unless you can find someone who is parting with some nicely done iron heads so THEY can upgrade.... Lite weight pistons/rods for a Buick are NOT CHEAP!!!
I went over to Gary Paines house tonight , and he has a set of pretty welll ported ron headsfor a decent price I may use theese. also htinking of using the stock rods just having them reconditiond. still going with light pistons though. I dropped the block off at the machine shop on thurs. so I need to make some decisions and look for some parts pretty soon. Chris
For a 12 second motor use the stock rods. Just have them shot peened, polished and resized. My motor's not in yet but everything I've heard says they are fine.
you can use the stock rods ,just put some good bolts in them. i use stock rods in my aluminum head 464 and im running 10.90s with out a problem . i would go with the aluminum head option if you dont mind spending the money , it just doesn't make sense to spend money on those old iron heads because , sooner or later your going to want to make more power and you'll have to get better flowing heads . just my opinion good luck with your project,,..mike :TU:
