Just found this site and I'm amazed at the wealth of information being exchanged. I have a few questions: I just bought a 1967 Skylark 2 dr hardtop (not GS) with a 1976 455 that has GS455 stickers on the aluminum valve covers, 1968 430 heads, an Edelbrock 750 cfm carburetor with an Edelbrock aluminum intake manifold. The automatic transmission is a later model 350. All this info comes from the person I bought it from as I haven't verified it yet. I'm confused about the GS455 stickers; My understanding is the 455 started in 1970 in the GS455 and was used in various cars from 70 - 76, but what makes a GS455 engine or is there one? How do I verify it? By 1976 the horsepower and compression were greatly reduced but do the 1968 heads improve on the 1976 engine? I would like a mid 12 second car, so any suggestions or list of mods, best transmission (TH400?), needed suspension upgrades, tires, etc. is greatly appreciated. :beer Bill
I think the "GS455" stickers were just pasted on there for appearance. How well it runs and how fast it goes is all that really matters unless you plan on showing it.
Re: more answers Engines up to and including 1970 were the higher compression engines. The GS designation meant the car had heavy duty springs, shocks, sway bars, lower restriction exhaust, posi traction diff. ,rally wheels, quicker ratio in the steering and a quicker advance in the dist. Really this was a ''handeling pkg'' mostly from 1967 on. from 1966 to 1965 there were more engine options, like the super wildcat s ect. The nail heads had hotter cams, dual 4 carbs, big exhaust, quicker dist advance, along with the above mentiond ''handeling pkg''. From 67 on the performance engines from Buick were designated ''stage 1's'' , stage 2, ect. The 1953-1966 engines were 322-364-401-425 cu. in. with forged steel cranks, forged steel rods, and a very strong ,narrow engine block. These were called ''nailheads'' by the rodders and mechanics of the day. the 1967 and later engines of 400-430-455 cu. in. had strong blocks and a very large cast nodular iron crank with forged steel rods. These were the basis of the ''stage'' engines. The earlier engines have the dist in the back while the later have the dist in the front. Only the nailheads have the dist in the back.
Hi Bill, sounds like a decent combo. The '75 & '76 pistons actually have less dish than the '71 - '74, but the compression height is about 0.040" down in the hole, so even though the early heads bring compression back up (mid 8:1 to 9:1?), the quench suffers a bit. Earlier pistons, forged if you're going to beat on it, would be a good way to go. As far as actual compression ratio goes, it depends on head gasket thickness, deck height and other factors...you won't know until you actually measure everything to know where you are for sure. Devon
but what makes a GS455 engine or is there one? noone cares about whether or not the engine is 'GS' as the VIN engine code on a Gran Sport was often the same as the base 455 A-body v8. what everyone keys on is 'Stage 1' ( Factory or Dealer installed ) which is coded in the VIN and EIN post 72 or 'Stage 2' ( Dealer Installed only and very, very small numbers of pieces in the wild ). noone looks for 'Stage 3' parts as these are experimental pieces, usually with production numbers <10 and never 'officially' available to the public at all. the primary defining characteristic of the Stage 1 engine is the oversize valves. there are also other Stage 1 specific pieces such as the carb, fuel pump, trans and distributor but those are mostly desired for restoration/judging purposes. the Stage 1 cam is hotter than the normal factory cam but modern cams are much better so most people don't bother with it. but do the 1968 heads improve on the 1976 engine? yes, definitely. the combustion chamber size in the 1967-69 heads is 68cc ( even smaller if Stg1 valves are installed ) while the 1975-76 heads are 10cc larger. perhaps more important, there is no quench area in the 76 heads whatsoever. being 1968 castings, you might also have 'big port' pieces: http://www.teambuick.com/forums/view.php?pg=casting_numbers_big_block ask the previous owner what pistons he has in the car and if the exhaust manifolds are 1967 pieces. I would like a mid 12 second car, so any suggestions or list of mods, best transmission (TH400?) TH400 is going the wrong way if 1/4 mile speed is your priority. the TH400 is more durable in stock form and will likely live longer but it's also heavier with significantly more rotating mass. IIRC, every additional pound of rotating mass is approx equal to 4 lbs of dead weight on the car. 'best' auto trans would be either a race prepped 200r4, a mid-80s turbo v6 200r4 ( factory heavy duty version ) or your existing TH350. needed suspension upgrades, tires look around in the 'Hides' sub-forum. much larger than stock wheels and tires will fit under the fenders.
