best intake choice for 73' 455 performance

I've recently dropped a 72/73' 455 into my 68 skylark, and to be quite honest, feel like I might have made a mistake, as the 350 before it had more hp. However, I think that in the long run the 455 will pay off with some mods. So far I've dropped a cam in, bore it .30 over with performance pistons, and replaced the distributor with one of those accel supercoil hei deals. I also replaced the powerglide with a 400 tranny, and put on some big flowmasters. I guess my question is what should I do next, because I'm still not blasting off the line. I'm thinking about switching the heads to 430 or maybe 400 heads and want to know what it would take and how they'd do. First of all, though, I want to change my intake, so I was hoping someone could tell me what works best for them, with the stock quadrajet. Any help would be greatly appreciated.

Sorry that this doesn't directly answer your main question, I hope someone else will chime in.

The '72 motors had a different method to rate HP than th '68 motors, so in reality you probably have quite a bit more HP. It might just need some "waking up". Make sure you have the tuning throroughly done, and then just let the engine breathe. Headers, intake and cam are your best bets for breathing.

-Bob C.

as the 350 before it had more hp.

are you talking about your butt dyno or the factory #s? if your butt dyno isn't being satisfied there might be a fairly serious issue. you can't swing a dead cat without hitting a built Buick 455 that will push over 500hp.

The '72 motors had a different method to rate HP than th '68 motors

bobc is correct. 71 and older, the factories rated engines in gross hp ( no belt driven accessories, often open pipes or headers, etc ) while 72 and newer is rated in SAE Net hp.

as far as the intake, what is the purpose of the car? full on strip/stop light drags or do you also intend to cruise?

there isn't any practical difference in the factory intakes 67-76 aside from some emissions. if you want a more serious race motor you'll be looking at the www.taperformance.com single plane.

What cam did you put in it. Many choices will kill a motor off the line without a matching torque converter.

It sounds like you have done many things which should make you happier with the 455 than the 350. The pistons sound like they should have made up for any shortcomings the late 455 may have had. Do you know what dish or compression ratio they were supposed to have had?

Perhaps you should consider takeing it to a performance tuner with a dyno. You should be happier with the 455 than the 350.

I appreciate the immediate replies to my situation. Still haven't dyno'd it, but I believe I've determined part of the problem. First of all, I believe my tranny, which came from a 73 riv is leaking(and pretty worn out). Next gripe is the short to that accel hei that I bought. The plunger in the cap is darn near gone. This wiring issue is probably holding me back, and I'm about to figure it out(while replacing half of the distributor .. with a warranty this time) However, would some 68 to 70 400 or 430 heads do me some sweet justice, as I've heard, or should I keep the ones I have? I still don't have the #s for the cam I installed, and am not savy enough to attempt figuring it out. Newcomer when it comes to opening em up. Good advice will make me try anything though. Any help will be greatly appreciated and I'm obviously the man accountable. Just give me the brass.

Tranny:
if the TH-400 is causing problems you can also bolt up a TH-350 or 200r4. these latter two are not only lighter than a TH-400, they also have quite a bit less rotating mass. great for accelleration. :shifter:

you do give up some durability in stock form but either can be built to hold 600hp. the 200 will also give you overdrive AND a shorter first gear.

Distributor:
the 350 and 455 use the same distributor, you just need to swap the drive gear at the bottom of the distributor shaft. so if you've still got the 350 sitting around you can cannibalize the distro off of it and it won't cost you anything.

One thing I've seen many times. Too much cam for the application. Very important, WAS IT DEGREED??? Upon installation. I just recently did one on a "W" engine (409) & it was at 102* instead of 109*, way off & the reason it was so "Peaky". Did another 6.0 for an Avalache last week that was 99 1/2* instead of 107*. Can't rely on anybody, ya' gotta check!!!!!!

Tom T.

don't forget, you had a super turbine 300 (a power glide with a variable pitch stator), so I'm guessing your rear axle ratio is probably 2.75 or even LOWER numerically like 256.

if you dont want to go to the automatic with overdrive (700R4 or 200R4) you might want to swap out the rear end gears to 3.55 or therebouts.

And, if you're looking for snap off the line drop in a 2-2500 rpm stall converter.