From the H.A.M.B. :
This one is for C9 and the maybe three other folks here who already know about the unsung lightweight hero of the smog motor era...the Buick 350. (And for others who are interested, naturally!).
Available from 1968 to 1980 in various Buick models, the 350 engine (or 'small block' as many call it) was a modern, overhead valve engine designed to replace the nailhead as the company's base V8 engine. The factory produced both two and four barrel versions of this engine, and it was also loaned out to AMC for use in some of it's Jeep models.
Looking much like it's bigger 455 brother, the 350 Buick can be quickly separated from it's Pontiac and Oldsmobile 350 cousins by noting that the distributor is in the front of the engine at an angle. Cylinder numbering is the same as a small block Chevy with odd numbered cylinders on the left (driver's side) bank and evens on the right (passenger's side) bank. Firing order is the standard 1-8-4-3-6-5-7-2 for the Buick 350 and the distributor rotates in a clockwise direction.
The odd thing about the Buick 350 is that it is nearly a perfect 'square' engine, featuring a 3.800" bore and a 3.850" stroke from the factory. This gives the engine a nice, flat torque curve, but hampers any screaming, high rpm dreams you may have had for this particular mill! Still, it is a great performer if built to the conservative side, allowing it to take full advantage of it's natural low and mid-range capabilities.
Other specs for this engine include a main journal diameter of 2.9995" and a rod journal size of 2.0000" with between .0004" and .0015" clearance called for on the mains and .0002" and .0023" on the rods. End play should fall between .003" and .009" on the crank, with thrust on #3.
These engines were a product of the smog era, and as such, they saw compression drops throughout the 70s. They held at 8.5:1 up until 1975, when factory specs dropped to 8.0:1 for the remaining span of the engine's production. This makes them excellent performers on low octane pump gas, and works well for a daily driver, but to wring any serious performance out of them will require a piston swap or some minor cutting on the decks or cylinder heads to acheive a more robust, yet still streetable compression ratio of around 9.0:1 or 9.5:1. Any more than that is really too much for a street engine relying on questionable quality fuel from random service stations!!
Crane Cams offers several hydraulic grinds, and one solid lifter grind for the Buick 350 engine. Here are the part numbers and specs, starting from mildest and working up from there.
Part # 710511
Duration @ .050 = 194 I/202 E
Advertised Duration = 252 I/260 E
Lobe Separation = 112
Gross Lift = .400 I/.416 E
Part # 710531
Duration @ .050 = 202 I/210 E
Advertised Duration = 260 I/268 E
Lobe Separartion = 112
Gross Lift = .416 I/.432 E
Part # 710571
Duration @ .050 = 218 I/226 E
Advertised Duration = 276 I/284 E
Lobe Separation = 112
Gross Lift = .448 I/.464 E
Part # 710631
Duration @ .050 = 226 I/234 E
Advertised Duration = 284 I/292 E
Lobe Separation = 110
Gross Lift = .464 I/.480 E
Part # 711161 (solid)
Duration @ .050 = 238
Advertised Duration = 304
Lobe Separartion = 108
Lash (hot) = .022
Gross Lift = .512
Note that the solid lifter cam is a 'square pattern' grind. Solid cams can be 'tuned' somewhat by experimenting with different valve lashes within a given range, so that this cam can be effectively run as a dual pattern cam to some degree with slight changes in the lash setting between the intake and exhaust valves. Not really an issue, as I doubt that anyone who isn't trying to build an all-out racing version of the Buick 350 would go down this road!
I used an earlier version of the 710571 hydraulic grind in my ex-wife's 350 engine and it worked out well with the stock intake, a Carter AFB, recurved HEI distributor and dual exhaust. It had a nice lope to it and really came on strong in the 2200-5000rpm range...making her old sled get up and boogie, much to her delight!
(The lopey idle also attracted curious glances from guys driving musclecars and hot rods!)
Swapping in a performance cam is just as simple on a 350 Buick engine as it is on nearly any other. There are some funky nylon rocker arm retainers that you will have to pop out with a screwdriver to pull the rockers off, however. I was able to re-use mine, but they DO become brittle with age and should be replaced if they crack or look suspect. Just something to be mindfull of.
The stock 4v factory intake works okay on a street engine tailored for mild performance useage, but it is a heavy cast iron sumbitch! The best game in town by FAR is the 350 Stage 1 aluminum dual plane intake manifold available from TA Performance for the Buick 350. It works well up to 7200 rpm, which is more than most semi-stockers will see. (455 intakes will NOT fit a 350, by the way!). TA Performance also offers several performance cam grinds for the underdog Buick motor, and they are currently the leader in supplying parts and knowledge for these engines.
Check out TA Performance at :
http://www.taperformance.com/Headers for a rod or custom application are likely going to fall to something home-built starting with a flange made from an exhaust manifold gasket...but the 68-72 Skylark manifolds work okay for a mild application. (That's what I used on my ex's car...a buddy had dropped a 455 into his 71 Skylark, and I got the old 350 manifolds for free!).
Yes, the Buick 350 is a rather obscure oddity...but that's part of it's charm! If you're looking for a cheap, lightweight powerplant to move your project down the road, you may want to consider one of these long stroke small blocks! Manual and automatic trannys will work, and any B-O-P pattern TH350 or TH400 will work with your favorite converter, shift kit, etc. I know manual transmissions were available behind the 350 Buick in Jeep applications at least, so with a little parts scrounging, you can run a stick shift behind one of these engines.
(I seem to recall a friend's neighbor owning an early 70s Buick Apollo with a 350 and a 'three on the tree'...but I can't be sure now...that was well over 20 years ago!)
So...the 'secret' is out!! Buick 350 "small block" engines make interesting alternatives to the more common fodder, and offer decent performance in a reliable and lightweight package with the distributor up front to make firewall issues simpler for anyone considering a swap.
--------------------------------------------------------------------------------
Doug in Az
My Old Monza now lives in Arizona with its newest owner.
The 90's just keep rollin' along........
1990 Chevrolet Silverado Regular Cab Long Bed 350 TBI V8 700R4 118K miles
1992 Pontiac Sunbird Coupe 2.0 OHC MPFI I4 TH125C 157k miles