well i got a 455 and i will be doing a swap real soon for my 70 skylark. i am working on cleaning the engine up a little, but not doing a whle lot because i am not doing a rebuild, etc at this moment because of my money situation, will probably do this next winter when i am out of college and have a full time job. initially i am going to put on headers and exhaust, considering i wont be changing this no matter what more improvemnts or performance i will be doing. i am thinking 2.5", because i wont be needing 3" at least i dont think, but correct me if i am wrong and should go 3" right away. i also was planning on doing a TA intake right away, but didnt know if i should wait till i do a full rebuild, and get a better cam, etc... let me know on your thoughts wise folks. so to sum things up here is my time frame: Now: exhaust and headers, and maybe intake (any ideas would be helpfull), full front end haul to support 455 and just for safety. 1-2 years: full rebuild of motor with upgraded performance parts (intake, cam, heads, etc...) and a new transmission (still have the 350) let me know if you thinkg i should do other stuff right away, or wait on things. Nate
The intake will be a waste of time and money unless your going to get into the motor, the stock intake flows well enough to support stock compression/cam/carb. You could install a 1" spacer under the carb and probably see the same increases that a new intake will give you. 2.5" exhaust is more than plenty untill your in the 475hp-500hp range. Put a new rear main seal and oil pan gasket on it while it's out, they always manage to start leaking right after their installed if you don't. Install a booster plate and adjustable regulator on the oil pump and shim it properly (only about $40 in parts). Headers will wake it up. Buy a quality set or you'll be fighting leaks forever.
Nate- Before I could recomend anything, I would have to know the year, and what has already been done to the engine. If it is a low compression motor, I'd locate some pre 71 heads and start from their. a fresh valve job and a possible cam swawp should run about 400 bucks at most. If you do plan on rebuilding it, you could buy some parts that you can use after the rebuild, like the headers or intake. I would definatly swap the heads and put in a bit of a cam. that shouldn't cost too much. :beer Joe
Nate- The first thing I would do is make darn sure the exhaust manifolds will even come off without breaking bolts. I couldn't do it on mine and it really tossed a wrench into the works when I had to pull the heads too and send them to a machinist to remove the broken bolts. When getting tubular headers, something I thing some folks forget is that the starter motor and tranny coolant lines are right there too. I have a weak shift problem which I think is traceable back to the fact that the coolant lines for the tranny are too close to the header on the passenger side. The starter should be replaced, unless it's brand new. The starter will get heat soaked like crazy now, and you should get a new heat sheild from TA. It will be a tight fit with the stock type starter and TA's thicker heat sheild but don't skip this step or it will come back to bite you later on. So I recommend a tranny cooler and a new thick starter heat sheild. Also get the thickest battery cables you can find and install them. I'd also replace/rebuild all pumps. I know I'm not talking performance gains here but the aim is to get the engine to last long enough for some real performance work later on and now is the time to look at the water fuel and oil pumps really closely and do whatever work needs to be done so that you have a solid motor further on down the road to begin your performance work. Also I think I'd look at my tranny mount and my u-joints if I were you, while the engine's out. It will never get easier to do the tranny mount, and new u-joints are cheap insurance that the torque you're going to make won't cause unseen driveline problems. Change your rear end lube too while you're at it, it's easy and good insurance. Building for durablity is boring but I think it's job #1 when doing engine work. I hate paying for things twiceou:
I AGREE, you got some good advice, i will throw in my 2 cents, the stock intake is fine besides a 1" spacer, you can have the plenum under the carb milled out, the after maret intakes look cool but really only add high rpm h/p, and you got to build a moter that can take advantage of this, starter shield a must, oil booster plate, 70 heads would give you the most torque, maybe clean up the combustion chambers, to help detonation, there are a lot of cams to choose from, just get one the manufacture recamends for your set up, 3'' is good but you wont see eney differance till you get over 500 h/p i went with 2.5'' just because the 3'' looks like a school bus exhaust to me. i also want to keep my car looking as stock as possibly, i tryed with my 1 7/8 headers uncaped and only went 1 mph faster with no e.t. inprovment, that was due to the loose of low end torque. if your moter is good do your rearend, on my last 455 witch was a little tired i went from 308 to 373 gears, and it felt like i had twice the h/p, but it didnt take long till i threw a rod, i didnt have good enough oil pressure to be spinning up that fast, so make sure you do some oil mods, the booster plate is were to start
Headers and exhaust are the biggest performance bang for the buck. Mine are 2 1/2" and I think they work just fine. I also run a Dr. Gas x-pipe kit. Lots of past threads on the benfits of that for your reading pleasure. Spend the money to get the aluminum-ceramic coating (Jet Hot etc) on the headers so they will last. Also basic tuning of distributor and carb jetting. Big bang for the buck there too, and cheap.
